Interpreting Our World: 100 Discoveries That Revolutionized Geography

For millennia, people longed to see their home, the Earth, from above. Socrates, for example, said, “Man must rise above the Earth—to the top of the atmosphere and beyond—for only thus will he fully understand the world in which he lives.”

Geographers have always been interested in multiple perspectives of the Earth. Throughout the millennia, people made drawings—on cave walls, stone, and paper—of what they knew on the ground: maps. Geographers became adept at drawing aerial-perspective views of cities and regions, such as the Vista de Venecia (View of Venice) by Jacopo de Barbari, which dates as far back as 1500. By the early 1800s, geographers and geologists began creating cross-sectional maps of what is underground (see Smith, William). Despite these drawings, they still wanted to see the Earth from above, as a bird does. How could geographers help their own community as well as the general public understand what the Earth looks like from above? The revolution came with photography (see Photography). Immediately upon its discovery, geographers and photographers were keen to take the new technology to the skies. But how could they, in the decades before airplanes, rockets, and satellites?

On October 13, 1860, James Wallace Black and Professor Sam King photographed Boston from an altitude of 1,200 feet (365 meters) in King’s hot-air balloon. A few years later, in 1868, Gaspard Felix Tournachon, later known as “Nadar,” used a tethered balloon to photograph Paris from above, after his 1858 Bievre Valley photographs were lost. In May 1888, Arthur Batut became the first photographer to send his camera into the air on a kite. Responding to a rubber-band-driven device, a slow-burning fuse actuated the shutter within a few minutes after the kite was launched. Once the shutter was released, a small flag dropped, alerting the ground crew that it was time to bring down the kite. On the kite, an altimeter encoded the altitude at the time the film was exposed. This allowed for later scaling of the image. By 1906, George Lawrence was using between 9 and 17 large kites with a camera weighing 49 pounds (22 kg), taking some of the largest exposures (18.9 by 48 inches; 48 by 122 cm) ever obtained from an aerial platform. The camera was raised nearly 2,000 feet (610 m), and an electric wire was used to operate the shutter, yielding a negative. His photographs became famous because they showed San Francisco five weeks after the famous earthquake and fires.

Kites had their limitations, leading some to try birds. Julius Neubranner in 1903 designed and patented an aerial camera that could be mounted on the breast of a carrier pigeon. The camera weighed in at only 70 grams, light enough not to impede the pigeon’s flight, and could take automatic exposures at 30-second intervals along the flight line. Despite the difficulty of trying to make pigeons follow a designated flight line, these pigeon cameras were used in fairs and even for military surveillance. But it was airplanes, of course, that would provide the long-term, reliable, scientific solution. Beginning in the 1920s, the business of aerial photography expanded, as local governments and private industry realized that aerial surveys could be faster and less expensive than ground surveys. An important innovator during much of the 20th century in this field was Talbert Abrams. Born in 1895 on a farm in Michigan, Abrams learned to fly at the Curtiss Aviation School in 1916, where his pilot’s license was signed by Orville Wright. After serving as a pilot for the U.S. Marines in World War I, he became one of the country’s first airmail pilots in 1920. He then established ABC (Always Be Careful) Airline Corporation, and his J-1 biplane equipped with a homemade camera became his first photogrammetry aircraft. Before long, his renamed Abrams Aerial Survey Company had secured contracts with state highway departments, and in 1937 the company developed the P-1 Explorer, the first aircraft exclusively designed for aerial photography. The P-1 Explorer was distinctive in appearance, as its entire front was made of panels of glass, offering the pilot and the photographer unobstructed views in nearly every direction. During World War II, all branches of the military were using his aerial photography methods. His company, later sold to Curtiss-Wright, mapped 1,720 American cities, 515 counties, 48,000 miles of utility lines, and 5,800 miles of highways, and Abrams became known as “The Father of Aerial Photography.”

Aerial photograph of Boston taken on October 13, 1860, by James Wallace Black, who, with Professor Sam King, ascended to an altitude of 365 meters (1200 feet) in King’s balloon. Since that time, aerial photography revolutionized the field of geography by providing an accessible and accurate means of analyzing the Earth and the changes that occur on it. (Fotosearch/Getty Images)

Another key innovator was Sherman Fairchild, who developed an improved aerial camera. The company he founded, Fairchild Aerial Surveys Inc., landed a contract with Newark, New Jersey, in 1921 to conduct aerial mapping there, setting the stage for thousands of such contracts globally with hundreds of cities, down to the present time. His innovations also spread to designing the airplanes themselves, because Fairchild realized that existing airplanes were not suitable for the tight maneuvering and extreme conditions that were often encountered during the taking of aerial photographs. Fairchild’s company also developed a camera for NASA that was carried on Apollo 15, 16, and 17 to photograph the moon.

During these developments, the application of aerial photography to geographic problems and issues greatly expanded. Arguably, the most important and most frequent use of aerial photography for most of the 20th century was for mapping. National mapping agencies such as the U.S. Geological Survey in the United States and the Ordnance Survey in the United Kingdom began to use films as the basis of their topographic mapping programs. While both maps and aerial photographs present a bird’s-eye view, it is important to note that aerial photographs are not maps. Maps are orthogonal representations; they are directionally and geometrically accurate (though not perfect, as discussed elsewhere in this book). Aerial photographs, even with modern methods, have distortion resulting from the topography of the Earth, the tilt of the aircraft, and the mechanics of the camera lens. However, aerial photography, combined with field crews that ground-truthed these photographs to surveyed locations, allowed cartographers to mathematically correct their distortions and make two-dimensional maps at increasingly detailed scales, such as 1:24,000 and even 1:10,000, for entire countries. In addition, taking photographs that slightly overlapped allowed cartographers to use the rapidly advancing science of photogrammetry to create contour lines showing elevation on those maps. Later, they used those same overlapping techniques to create digital elevation models that even more closely represented the three-dimensional Earth.

Another primary use for aerial photography during its first century was for military reconnaissance. Even as far back as World War I, aerial photographs were taken from airplanes, although these photographs often were distorted, because the speed of the shutters was too slow in relationship to the speed of the airplanes. As the war was coming to a close, Sherman M. Fairchild was able to reduce the distortion problem by developing a camera that contained the shutter inside the lens. When aerial photography expanded during World War II, geographers were sought as trusted and expert advisers to governmental military operations around the world. In perhaps the most famous example, the interpretation of aerial photography played a critical role in the discovery of the Soviet construction of missile silos in Cuba during 1962 before and during the Cuban Missile Crisis. More recently, aerial photography has been instrumental in bringing global attention to humanitarian crises in Uganda, in Darfur, and in Syria, although satellite imagery is used even more frequently due to its advantages in dissemination and temporal and spatial coverage.

The importance of aerial photography to the study of geography and the understanding of the Earth cannot be overstated. With aerial photography, geographers had the vantage point that for centuries they had dreamed about. Aerial photographs “stopped” the action on the ground at the specific time at which they were captured, offering a permanent record on film. Black-and-white photographs offered 256 gray tones that enabled geographers to interpret features on the ground; with color photographs, they could use hue, saturation, and value. Perhaps more importantly, film sensitive to different wavelengths than the human eye is sensitive to could also be used to take photographs from airplanes and, later, satellites (see Remote Sensing). This allowed geographers to image the Earth in color infrared and in other wavelengths, which in turn allowed them to “see” things such as vegetation health and underground ore bodies that film sensitive to visible wavelengths could not show.

Furthermore, once aerial photography became easily reproducible and available thanks to the advent of the mass production of contact prints from film, geographers could now order aerial photographs to be taken at different times. By studying aerials taken at different times of year and different times of day, geographers gradually learned how daily and seasonal cycles are reflected on the Earth’s surface. Over time, these photographs became a critical component in the understanding of how physical and human-caused processes change the Earth. In terms of natural processes, everything from volcanic eruptions to coastal erosion to sea level changes could be observed, and in terms of human influence, urbanization, agricultural practices, and hundreds of other influences could be examined. Land-use planning on local, regional, and even national scales could be conducted. Thematic maps of geology, land cover, biomes, and many other themes could be accurately carried out and examined. Studies produced by geographers and other disciplines using aerial photographs came to be used by city planners, wildlife habitat managers, agronomists, and many others in their everyday decision-making. The developments in aerial photography and mapping, in turn, gave rise to geographic information systems (see Geographic Information Systems) and progressively more analytical and efficient means of creating maps and data to study the Earth as it really is—a changing, living, dynamic planet.

See also: Geographic Information Systems (GIS); Photography; Remote Sensing

AGRICULTURE

Modifying Planet Earth

According to the Food and Agricultural Organization of the United Nations, agricultural land covered 38.4 percent of the world’s land area as of 2011. As this is by far the single largest type of land use by humans, agriculture has always been a key area of study for geography and also has been influenced by geographic research. One could argue that agriculture enabled geography and all other research to occur in the first place, since the development of agriculture enabled human populations to grow, modern societies to eventually flourish, and disciplines such as geography to become established. Agriculture represents the largest manifestation of humans impacting the environment, and given the importance of this theme in geography, it has been extensively studied as a core theme in geographic research (see Defining Geography).

Agriculture includes the cultivation of plants, animals, fungi, and other life forms not only for food, but also for fiber, biofuel, medicine, dyes, resins, perfumes, oils, and other products. Given the number of people globally involved in agriculture or industry enabled by agriculture (up to 45 percent of people, according to some sources), geographers have also studied the practice of, economics of, and changes over space and time of food production. This study ranges from the soil condition of individual fields to regional studies of the aquifers being used for irrigating those fields, to global trade in everything from coffee to cantaloupe to cereal grains.

Agricultural issues have long been geographic issues. Where crops can be grown is influenced by climate, precipitation, latitude, elevation, proximity to coasts, landforms, soil, bedrock, river systems, aquifers, and many other factors of physical geography. Yet it has long been tied to cultural geography as well: From 1450 to 1860, for example, the enclosure movement in England consolidated communal fields into individually owned and managed farm plots, first for increasing pasture lands for manor lords, and then for the sake of agricultural efficiency. More than changing the amount and types of crops and livestock that could be raised, this enclosure had deep effects on national identity, internal migration and international emigration, and people’s sense of place. During the 1600s, advancements in agriculture, including more efficient production and distribution, enabled more people to live in cities, which in turn fueled the industrial revolution a century later. Agriculture has influenced cultural geography—the food and culture of a region is inextricably linked to the crops that can be grown there and the way that they are grown. Agriculture has provided a way of life, art, poetry, music, and drama for millions of people through the centuries. It has become one of the essential human experiences for nearly all the people on Planet Earth until relatively recently, with the rise of urbanization and the migration of people from rural lands.

Agriculture has also influenced physical geography. Worldwide, thousands of square miles of wetlands and former ocean waters have been drained for agriculture. Aqueducts and canals have enabled cities to be built in the desert, such as Las Vegas and Phoenix, and have changed entire river systems (see Canals). More than 40,000 large dams have been constructed worldwide, many for agricultural purposes, altering river flow, water chemistry, and local terrain. Worldwide, many aquifers are being depleted more quickly than they can be replenished, in order to irrigate crops and pastures. Soil erosion was a notorious issue of the Dust Bowl of parts of the Great Plains in the United States in the 1930s, but it continues today in many parts of the world, displacing people, changing land use, and influencing even international migration.

According to the World Bank, 11 percent, or 3.7 billion acres (1.5 billion hectares), of the world’s land surface is used in crop production. This number represents 35 percent of the land deemed at least somewhat suitable for crop production. But most land not currently used in crop production that could be used in crop production is in Latin America and sub-Saharan Africa, which poses challenges for the protection of biodiversity and the economics of crop expansion. Another topic that geographers study is additional constraints such as low fertility, toxicity, high incidence of disease, or lack of infrastructure. Arable land per capita, due to expanding world population, will decrease from 0.45 to .20 hectares per person from 1960 to 2050. Crop production for the world is expected to grow from now through 2030 at 1.4 percent per year, but the projected increase in world crop production is growing at around 1.6 percent, due to increases in cropping intensities, expansion in the total area harvested, and growth in yields. While expansion in arable lands will remain important, there is an increasing reliance on irrigated agriculture, which is of concern to geographers and others who consider the sustainability of water resources: Agriculture accounts for 70 percent of global withdrawals of freshwater resources.

Geographers compare subsistence agriculture to commercial agriculture and the effects of agricultural policy on productivity and the spatial distribution of crops. Geographers study the influence of agriculture on the workforce. For example, according to the International Labour Office in Switzerland, in 2001, agriculture constituted approximately 70 percent of the global employment of children, and in many countries it employs the largest percentage of women in any industry. Geographers even study the attitudes of farmers toward the environment. With more people living in urban areas each year, urban agriculture is receiving increased research attention. With the quantitative revolution, geographers used the Von Thünen model to explain agricultural zones surrounding a city, with vegetables, fruit, and milk produced nearest the city, followed by timber for fuel and building materials, field crops, and finally, farthest from the city, ranching.

With the advent of the environmental movement, the rise of urban gardens, community gardens, farmer’s markets, and the local food movement has gained the attention of geographers (see Environmental Movement). More recently, issues of agricultural sustainability and resilience in the face of changes on the planet due to land use, urbanization, climate, and political instability have been important threads of research in geography. Geographers are also studying the health effects of genetically modified organisms and the contribution of agriculture to global greenhouse gases. With the rise of the global economy (see Supply Chain Management), agriculture has been intertwined with global migration and famines, which are, at their cores, issues of cultural and physical geography.

The study of agriculture, soils, food security, and other agriculture-related topics is an important part of many geography departments, or else is central to natural resources departments in which geographers serve as associated faculty. At the College of Agricultural and Environmental Sciences at the University of California, Davis, for example, researchers from a variety of disciplines model water quality as impacted by pesticide and nutrient inputs for watershed management, map biofuel and bioenergy crop distribution, examine social and economic factors affecting pest management decisions, and identify crop-disease infections for precision disease management.

Besides agriculture being a key influence on geographic research, geography has also influenced the development of agriculture. The holistic perspective that geographers have is beneficial to the science of agriculture, which is inherently tied to elements of the physical geography such as weather, climate, slope, aspect, elevation, ecoregion, ground and surface water, and biodiversity, but also of cultural geography, such as agricultural mechanization, historical land use, regional and international economics, behavior and consumption patterns, and pollution (as exemplified by the Merem 2011 study). In addition, the development of geotechnologies by geographers, such as GIS, GPS, and remote sensing, has revolutionized agriculture. It has influenced the way that many farmers irrigate, apply fertilizers to, harvest, and assess their crops through precision agriculture, as well as the way agriculture is managed by local, regional, national, and international agencies and authorities (see Global Positioning Systems; Remote Sensing). From the earliest days of GIS, it has helped farmers and farm service agencies analyze soil data, historical farming practices, topography, and climate data to determine the ideal crops to plant, where they should be planted, and how to maintain soil nutrition levels to best benefit the plants.

Real-time weather and flood information fed through the global sensor network can help those in agriculture prepare for natural hazards (see Internet of Things), and it helps the U.S. Department of Labor set crop insurance rates, and MODIS satellite infrared imagery can display weekly crop health. The Consultative Group on International Agriculture Research (CGIAR) identifies optimal sites for the production of roots, tubers, and bananas using data on crop rotation, fallow areas, demographics, and other information. The Commonwealth Scientific and Industrial Research Organization of Australia even tracks the behavior of insects to protect the country’s agriculture industry. Their research reveals key insights for decision-makers and planners that link the pattern of insect populations to the types of soil and crops. All of these efforts illustrate the applied nature of geography to enable wise decision-making (see Applied Geography).

Thus, agriculture has influenced cultural and even physical geography, has long been a focus of geographic research, and has benefited from geographic technologies. Given its critical importance in sustaining the expanding human population with finite resources, and given its close ties to physical and cultural geography, agriculture will continue to be an important focus for geographers.

See also: Applied Geography; Canals; Defining Geography; Environmental Movement; Global Positioning Systems (GPS); Remote Sensing

AIR TRAVEL

Compressing Distance, Altering Geography

It is May 2, 1952. The first passengers have boarded the de Havilland Comet for a BOAC airline flight from London to Johannesburg. The era of commercial jet passenger air travel has arrived.

Although the first untethered human lighter-than-air flight took place during 1783 in a hot-air balloon designed by the Montgolfier Brothers, the balloon and the dirigible that followed were limited in speed, ability to steer, and dependency on the correct atmospheric conditions. But the age of the airplane—starting with the Wright Brothers’ powered and controlled flight on December 17, 1903, at Kitty Hawk—began a series of revolutions that would radically change the physical and cultural geography of the planet. Rapid advances followed: In 1914, the first scheduled flight with a paying passenger took place between Tampa and St. Petersburg, Florida. Alcock and Brown made the first transatlantic flight in 1919, Lindbergh flew solo across the Atlantic in 1927, and Smith made a flight across the Pacific in 1928. The Douglas DC-3 became the first profitable passengers-only airplane, but throughout this period, long-distance air travel was not feasible—airplanes that landed in water were still necessary for long hauls. Only government officials and the wealthy could afford to travel—that is, until the de Havilland Comet changed all of that.

Following the de Havilland Comet, which suffered crashes and was reengineered into improved models, an even more widely used and economical passenger jet was introduced. This passenger jet, the Boeing 707, took its maiden commercial flight in October 1958, via a Pan American World Airways route from New York to Paris, stopping to refuel in Gander, Newfoundland. The 707 was followed over the decades by the DC-8 and other models from Boeing, Airbus, and other airplane manufacturers. As solid-state electronics, satellite communications, computers, digital maps through GIS, and GPS (see Geographic Information Systems; Global Positioning Systems) became standard parts of airplanes, they became safer. Cessna, Piper, and Beechcraft made enormous expansions in light aircraft production. Airplanes began to replace ocean liners, and then intercity trains, as the primary mode of travel for many sectors of society. By 2014, the world’s five busiest airports—Atlanta, Beijing, Dubai, Tokyo, Los Angeles, and London—collectively handled 397 million passengers, representing over 5 percent of the entire world’s population. A wide range of cargo is shipped via airplanes as well: The United Parcel Service (UPS) airline is the ninth largest in the United States, shipping over two million air express packages each day. Air-travel advances continue to be made, including privately funded aircraft for space flights and the use of alternative designs and fuels, such as ethanol, electricity, and solar energy.

Air travel became the primary mode of travel for so many sectors of society that it radically changed how those sectors functioned. One of these sectors is travel by world leaders, who regularly meet face to face or visit a site where an international crisis is occurring. Networks of sports teams were able to expand, and due to the ease of travel between cities, university and private regional and national teams were able to connect rapidly. For example, U.S. major league baseball had been confined to cities in the industrial north-central and northeast states, all within a day’s rail travel from each other; air travel enabled a rapid expansion to the south and west. The modern Olympics, to which many countries send hundreds of athletes, is enabled by air travel. Even more impactful on a global scale and on a daily basis has been overnight package delivery, made possible by airplanes and depended upon for daily world commerce.

Even from its very beginnings, air travel deeply impacted and was impacted by political geography. Both world wars supplied pilots later used in commercial aircraft and supplied technical innovations that impacted world aviation. In 1919, the Paris Convention stipulated that each country controlled the airspace over its territory. In Europe, governments established new passenger airlines. In the United States, the government heavily subsidized the delivery of airmail, which hastened the first major U.S. passenger airlines and accelerated the velocity of the money supply, spurring world trade. Following the Cold War, the opening of Siberia to international flights permitted more efficient linkages between London and Tokyo, New York and Hong Kong, and Vancouver and Beijing. The 1944 Chicago Convention established geopolitical guidelines of international air operations, or “air freedom rights.” Today, hundreds of carefully negotiated bilateral air services agreements (ASAs) are in place, specifying the airlines that can serve specific cities, equipment, and frequency. Some “Open Skies agreements” remove some of these restrictions. Alliances between airlines are common, which include booking systems, selling agreements, optimization of connections, city specialization, and fast reorganization of hubs—all of which are intertwined with geography.

Air travel has negative impacts on the environment. Powered aircraft release pollutants into the atmosphere, including greenhouse gases such as carbon dioxide (CO₂). One of the targets of the environmental awakening of the 1970s was the Concorde, which ushered in supersonic transport, because of the pollution it generated at higher altitudes (see Environmental Movement). Despite improvements between 1960 and 2000 of 70 percent in fuel efficiency, air travel is still largely dependent upon fossil fuels—their availability, their price, and their political implications. Vast tracts of impermeable surface accompany many of the world’s over 41,000 airports, particularly those that became international hubs, increasing their size to accommodate larger aircraft and increased number of passengers. Land adjacent to airports is devoted to the transportation-related sectors, including rental car agencies, cargo transport, and superhighways. Air travel is also affected by the environment; for example, delays caused by volcanic eruptions, including that of April 2010, when Iceland’s Eyjafjallajökull volcano erupted.

Today’s aircraft (except for the now-defunct Concorde) are only about as fast as was the Boeing 707 airplane 30 years ago. However, deregulation and privatization of the airline industry during the 1970s, along with an increasing number of “low-cost” airlines, increased fuel efficiency, ability to stay aloft longer, and an expanding global middle economic class, has led to an ever-widening set of cities that airlines serve. In geographic terms, this has lowered the cost, or “friction,” of distance; one of its results is the fostering of economic globalization. Manufacturers, especially those producing microelectronics components, such as Intel, depend upon air transport to tie together their spatially disaggregated operations (see Supply Chain Management).

Air travel has also affected the geography of disease. In 2014, much of the world’s media was focused on the spread of the Ebola virus from West Africa to other parts of the world as a result of infected airline passengers. More common, however, is the regular transport of influenza and other bacteria and viruses, as well as seeds and other plant material that can inadvertently cause harm in a faraway country because it is carried—however inadvertently—by an airplane passenger.

Air transport, particularly the hub-and-spoke model that many airlines use for routing their passengers, has been a mainstay of geography education for decades. This pattern is centered on the major airport, where a single airline is often dominant. Low-cost carriers have impacted geography recently by increasing the number of people who are able to travel, and by the focus on secondary airports, affecting land use nearby and traffic patterns in the entire metropolitan area that these airports serve.

Less measurable but equally important is the impact that air travel has had on cultural geography. By the year 2012, one million people were airborne at any given time, somewhere in the world. During that same year, 2.4 billion passengers were logged by 725 airlines on over 33,000 flight routes. These statistics show that air travel has tied together the planet as never before. The Boeing 747, for example, nicknamed the “Pacific Airliner” because of its significance in drawing Asia closer to the rest of the world, had a longer range than its predecessors. This occurred in part because airlines in Asia and the Pacific were major customers of the Boeing 747. It has enabled the global tourism industry, with subsequent development in corners of the planet previously inaccessible to all but local people. As a result, tourism geography has become a significant research strand in geography, examining the local to global impacts, and changes in time and space, of tourism.

Air travel has enabled families and friends to keep in touch as never before. Many people commute by air between regions and even between countries. It has positively impacted the ability of universities to serve the international community. Air transport has enabled the “always summer” phenomenon in food: Many people throughout the world have access to “summertime fruits and vegetables” no matter what season of the year it is where they live. This practice has led to the identification of the enormous cost of fuel used in transporting and overharvesting food. Air travel has enabled geographers to make field trips in hours to research sites that during the 19th century took weeks to reach. Air travel has endangered some cultures but also raised global awareness of their plight, resulting in steps to preserve and protect them. For the general public, air travel has increased awareness and appreciation of the core themes of geography—cultural diversity, the importance of water resources, biodiversity, landforms and the physical beauty of the landscape, and the uniqueness of places. A person walking through an international airport terminal likely sees people from a greater diversity of cultures in 30 minutes than that person’s grandparent did in his or her entire lifetime.

Air travel has been revolutionary for geography: It not only connects people and places as never before, but it also affects how people interact with, think about, view their place in, and study the world.

See also: Bridges and Tunnels; Geographic Information Systems (GIS); Global Positioning Systems (GPS); Roads, Ports, and Railroads; Supply Chain Management

AL-BIRUNI

Laying the Geodetic Foundations

Long before modern requirements for Earth measurements took shape, al-Biruni (, 973–1048) laid the foundations for the Earth’s physical properties. He believed the Earth rotated on its axis, and he proposed how time and longitude are related.

Born near Kath in Khwarezm in the Samanid Empire (modern-day Uzbekistan, near the Aral Sea), he lived much of his life in the Ghaznavid Dynasty, now east-central Afghanistan. His full name was Abū al-Rayḥān Muḥammad ibn Aḥmad al-Bīrūnī. Regarded as one of the greatest scholars of the medieval Islamic era, he studied astronomy and mathematics from Abu Nasr Mansur, whose family ruled the region at the time. He became proficient in physics, mathematics, astronomy, natural science, geography, history, weights and measures, religion, philosophy, grammar, medicine, and linguistics. Al-Biruni thus exemplified a polymath: a person of wide-ranging knowledge. He is estimated to have written 146 major works and about 13,000 folios, or the equivalent of 13,000 printed pages. He spoke Khwarezmian, Persian, Arabic, Sanskrit, Greek, Hebrew, and Syriac, aided no doubt by his conversations with travelers and from the traveling he did. For example, in 1017, he traveled to India and authored “Tarikh Al-Hind” (History of India). This account was so accurate—all the more remarkable since he was an outsider—that he was given the title al-Ustadh, or “The Master.” Rather than concentrating solely on India’s history, it also covered its astronomy, its astrology, the calendar, its systems of writing, its number system, and its geography. His work Shadows brings together mathematics, astronomy, and physics; for example, setting forth mathematical constructs such as the rule of three, irrational numbers, ratio theory, solving algebraic equations, geometry, angles, conic sections, the sine theorem in the plane, trigonometry, and even stereographic projection.

Stamp depicting Abū Rayḥān al-Bīrūnī, an influential scholar from west-central Asia who lived around 1000 CE. Al-Biruni propelled geography forward in many ways, including the calculation of the correct geographic coordinates of hundreds of cities and points of land, determining the Earth’s radius, and developing map projections. (jim pruitt/iStockPhoto.com)

While only one-fifth of his works have survived, there is no doubt that al-Biruni was revolutionary for several reasons. First, he was a modern scholar in the sense that he was an impartial researcher, perhaps best exemplified in his writings about customs and creeds of various nations. Second, he was revolutionary in that his geography was interlinked with history, mathematics, language, and other aspects of culture. Third, he was scholarly in a time and place of social unrest, producing an enormous volume of work. His influence is felt today far beyond the fact that the town near where he was born is now named Biruni. He made such serious contributions to the earth sciences, cartography, and physical geography that he is regarded as the father of geodesy, the study of the shape of the Earth (see Surveying). By age 17 he had computed the latitude of his hometown by observing the maximum altitude of the sun. By age 22 he had completed the writing of the book Cartography, which included reflections on numerous map projections as well as one of his own devising. Civil wars and unrest forced him to move to Rayy, near present-day Tehran, but even as a refugee, he took the opportunity to study once again. He met the astronomer al-Khujandi, and not long after, his knowledge seemed to surpass that of his educator and mentor: He pointed out errors that the astronomer al-Khujandi made about the latitude of Rayy and the obliquity of the ecliptic. Al-Biruni also exemplified the value of working with distant colleagues: By comparing the timing of a lunar eclipse between Baghdad and his hometown, he was able to calculate the difference in longitude between them. He did not just think about things—he built them, including astronomical devices for his measurements. He also worked to secure funding for his projects. He corresponded with scholars such as Avicenna and al-Sijzi. He wrote about time, the decimal system, the astrolabe, astronomy, astrology, and history.

Al-Biruni lived through civil unrest at least twice in different lands and probably was a long-time prisoner of the ruler Mahmud, but he overcame adversity to become one of the greatest scientists of his time and region. He treated science as a process of careful observations and testing of theories, and he saw each part of the process as rooted in historical context. He treated errors more scientifically than Ptolemy. Whereas Ptolemy’s attitude was to select the observations he felt were most reliable and meshed well with his theories, not telling the reader about observations he was discarding, al-Biruni took a different approach: He also chose some that he believed were more reliable, but he told the reader about the discarded observations. He was also meticulous, as is customary in modern practice, even in being sensitive to rounding errors.

In geography, al-Biruni introduced techniques to measure the Earth’s shape and size through solving a complex geodesic equation. He was able to measure distances on the Earth using triangulation. Triangulation was the technique that would be used 1,000 years later by GPS and in determining earthquake epicenters. His calculation of the radius of the Earth was 6,339.6 km, an accurate value not obtained in Europe for another 500 years, and also only 30 kilometers from its accepted value today of 6,371 km. One of his works contains a table that provides the coordinates of 600 places, including towns, river junctions, and points of land. Like other geographers, his extensive travels came in handy—he wrote Chronology in 1000, describing the history and geography of the Central and Western Asia region. Despite political divisions, Muslim lands represented a vast territory of common culture in which travel and research could take place. Like other geographers before and after him, he learned different languages to enhance his own learning and to spread that knowledge to others. He learned Sanskrit, for example, to help him understand and teach about Indian astronomy, astrology, chronology, and cultural and physical geography.

Like other geographers, al-Biruni’s extensive reading of other texts greatly aided his own research. His works On Shadows (ca. 1021), Tahdid (1025), On Chords (1027), On Transits, India (1031), and Al-Qanun al-Masudi, as well as the Arabic translation of Vijayanandin’s Sanskrit Karanatilaka, are all fundamental texts for the history of Islamic and Indian astronomy of the 8th through the 10th centuries. They are fundamental in large part because of al-Biruni’s extensive citations of earlier texts that he not only read but also understood. The texts are also filled with his own observations, which are among the finest and most detailed of the medieval period. In terms of advancing the data and methods of physical geography in terms of the composition of the materials that make up the Earth, al-Biruni described the ratios between the densities of such elements as gold, mercury, lead, silver, copper, bronze, brass, tin, and iron. He spread much of what was known about India 1,000 years ago to different parts of Asia, and because he was so active in a pivotal crossroads of the world, he spread knowledge about a wide variety of disciplines to faraway lands. His geodetic foundations were important to the evolving science of geodesy, and surveying is critical to all modern societies (see Surveying).

Thus, al-Biruni moved geography forward in several key ways, including the calculation of the correct geographic coordinates of hundreds of cities and points of land, determining the Earth’s radius, and developing map projections. On the subject of geography, he once said, “This subject is an all-important one for travelers and merchants. It is desired by princes and noble personages, sought for by judges and doctors of law, the delight of commoners and men of rank” (Said 1981).

See also: Anaximander; Eratosthenes; Ptolemy; Surveying

AL-IDRISI, MUHAMMAD

Pleasant Journeys into Faraway Lands

While Europe was in the midst of the Dark Ages in Europe (700–1300) and classical knowledge of geography had largely been lost, the study of the world by Arab geographers was actively encouraged by a number of rulers. The caliph al-Ma’mun (813–833) sponsored scholarship in Baghdad that led to the production of a large map of the world, now lost but described by al-Mas’udi (ca. 950) as even including an accurate distance of one degree on the arc of the meridian measured in Iraq. The great triumph, though, of Islamic mapmaking was the world map of Abu Abd Muhammad al-Idrisi al-Qurtubi al-Hasani al-Sabti, or simply al-Idrisi (ca. 1099–1166).

As al-Idrisi’s fame grew, he gained the attention of European sea navigators and heads of state, including the invitation by Roger II, the Norman king of Sicily, to serve in Roger II’s court and produce a world map. Al-Idrisi served in King Roger’s court in Palermo, on the northern coast of Sicily, for 18 years and finished the map while he did so. The map was no ordinary map; it was engraved on an enormous disc of solid silver—no small feat—and was two meters in diameter. It goes without saying that the map also must have been very heavy—indeed, it is estimated to have weighed 204 kilograms (450 pounds). The map was finished in 1154. It had a wonderful title, Kitab nuzhat al-mushtaq (Latin: Opus Geographicum), or A Diversion for the Man Longing to Travel to Far-Off Places. It is often referred to as the Tabula Rogeriana.

Tabula Rogeriana, a map drawn by al-Idrisi in 1154, is one of the most advanced maps of the ancient world. This is upside-down from the original, which had south at the top. At a time when Europe was in the Dark Ages and classical knowledge was largely lost or ignored, al-Idrisi had a great influence on geography and especially on cartography through his magnificent map of silver. (Universal History Archive/Getty Images)

Al-Idrisi also produced at least two geographical compendiums that also had wonderful titles. The first, Kitab nuzhat al-mushtaq fi ikhtiraq al-afaq, or The Book of Pleasant Journeys into Faraway Lands, or The Pleasure of Him Who Longs to Cross the Horizons (or “climates”), was also known as the Book of Roger. This book included a world map and 70 sectional maps. In the book, al-Idrisi explained that King Roger wished to know accurately the “details of his land and master them with a definite knowledge, and that he should know the boundaries and routes both by land or sea . . . together with [having] a knowledge of other lands and regions in all seven climates, whenever the various learned sources agreed upon them.” The second was Rawd-unnas wa-nuzhat al-nafs (Pleasure of Men and Delight of Souls).

Al-Idrisi knew about and drew on Ptolemy’s world gazetteer, and he sought to improve upon it. As his quote above indicates, he had a grand plan to describe the world in terms of seven climates. These were organized in tiers running from east to west. This was a foreshadowing of Koppen’s climate map 800 years later. Also foreshadowing the maps made for educational purposes during the late 20th century—some tongue-in-cheek—from the “perspective of the southern hemisphere” with south at the top, al-Idrisi’s map was oriented with south at the top. The map was vast in scope and detailed, including all of Europe and Asia and northern Africa. Despite the fact that East Africa and India were known to Muslim merchants, his map failed to include these, but perhaps the information did not reach him where he worked in Sicily. His book was published in Arabic in Rome, in 1592, becoming one of the first Arabic books ever printed.

Geography even played a role in helping al-Idrisi in his work. While Crusaders and Muslims battled in Palestine, and much of Greek and Roman thought (such as that of Ptolemy and Pliny the Elder; see these entries) had been neglected in northern and western Europe at the time, Sicily remained a meeting place where different cultures could exchange goods and ideas. Could al-Idrisi have had a wry sense of humor? Could the subtitle of one of his books, Pleasant Journeys, really be ironic? For surely, traveling in the 14th century was fraught with danger, from robbery, piracy, unimproved roads and trails, inadequate provisions, and hostile political powers. Or perhaps al-Idrisi just shared what is common to many geographers—a love of people, places, and travel that causes the difficulties to pale in comparison to the adventure.

Muhammad al-Idrisi was born in Ceuta, a Spanish city on the north coast of Morocco. He was a descendant of the Hammudids, a Berber Muslim dynasty, who claimed descent from the Idrisids, who are regarded as the founders of the state of Morocco, and for whom he is named. Like other geographers and cartographers, there is ample evidence that he was well-traveled, even by the age of 16, including journeys to Anatolia (Turkey), Córdoba in Spain, Portugal, the Pyrenees on the Spain-France border, the French Atlantic coast, Hungary, and York (England). But also like other geographers, he carefully listened and recorded information about places he had never seen, from other travelers, such as Islamic and Norman merchants who had traveled as far as India and China. In fact, some hold that he dispatched travelers and draftsmen to various locales, instructing them to make careful records of what they saw. Some also hold that he formed an academy of geographers and invited other scholars to collaborate with him there. Whatever the extent of this academy, it is clear that most of the 18 years he was employed in King Roger’s court was spent compiling and assessing information from the field, and a relatively short amount of time was spent actually writing the books and creating the map. Much of the assessment was devoted to reducing omissions and resolving contradictions in field notes and reports.

Also like some other geographers, al-Idrisi made contributions in other fields. For example, his contributions to medicinal plant sciences were many, stemming in part from his books in this field. The most popular one was entitled Kitab al-Jami-li-Sifat Ashtat al-Nabatat. Al-Idrisi reviewed and synthesized all the literature that he could find on medicinal plants, as well as associated medicinal herbs that were made available by fellow Muslim scientists, along with specimens compiled from his own research and travels. He also contributed to the discipline of botany, again with a focus on plants, describing the names of the medicinal drugs that were derived from them in a wide variety of languages, including Berber, Syriac, Persian, Hindi, Greek, and Latin. Al-Idrisi’s travels also informed his knowledge about the subject of zoology. Why? Because geography is holistic, and to many geographers, writing about the animals and plants of a region is part of the core of the “Earth-description” that gave geography its name.

Al-Idrisi’s accomplishments were revolutionary. For 300 years following the publication of his map and compendium, cartographers copied his map without alteration. He inspired Islamic geographers such as Ibn Battuta, Ibn Khaldun, and Piri Reis, as well as Christopher Columbus and Vasco da Gama. Europeans did not explore the source of the Nile for another 700 years, but when they finally did so, Samuel Baker and Henry Morton Stanley found al-Idrisi’s maps of lakes and rivers to be remarkably accurate. The positions of some of the features he mapped are still considered accurate in the 21st century. His descriptions of places provide some of the best records we now have of the world at that time, going far beyond mere place-name recordings. For example, he describes Chinese junks (ships) as carrying leather, swords, iron, and silk; he describes the glassware of the city of Hangzhou; and he refers to Quanzhou’s silk as “the best.” During the late 20th century, Clark Labs at Clark University named its GIS software “Idrisi” in tribute to the famous cartographer.

Whatever became of the huge, heavy silver map? It would have been difficult to misplace such a thing, and indeed, it was not misplaced and is not buried in the sand somewhere, waiting for a modern Indiana Jones to find it. Sadly, not long after it was completed, King Roger II died, and his court was attacked by Byzantine invaders. They melted down the silver map disk to make weapons. Al-Idrisi escaped with the Arabic version of the Book of Roger, but the Latin version was destroyed, and the book was not translated into Latin again until 500 years later. If the Byzantines had realized what they were destroying, they might have actually read the map and used it to make even bigger conquests than their silver weapons could ever have helped them achieve.

Even though the map was destroyed, al-Idrisi’s legacy and influence lives on to this day. And so does his statue. In his hometown of Ceuta, al-Idrisi proudly stands, fittingly holding his map!

See also: Pliny the Elder; Ptolemy

AL-JAHIZ

Connecting Food, the Environment, and Evolution

Over 1,000 years before Darwin and others embraced the theory of evolution, a zoologist of the ninth century CE, al-Jahiz (776–869), put forward some of the theory’s tenets. Al-Jahiz’s complete name was Abū’Uthman ’Amr ibn Baḥr al-Kinānī al-Baṣrī; the shortened version that he took for himself means “the goggle-eyed”; he had a malformation of the eyes. Born at Basra (in present-day Iraq) in about the year 776, he overcame childhood poverty—including selling fish along one of the canals to help his family—to become one of the great thinkers of his time. He dedicated his life to grappling not only with scientific problems, but with philosophical and theological ones as well.

Like other learned people of the medieval world, al-Jahiz was a polymath, an expert in many topics—science, as will be expanded on shortly, but also grammar and philology (the study of the structure and development of languages), lexicography (the practice of compiling dictionaries), rhetoric, and poetry. In fact, he is considered the founder of cultured prose literature in Arabic. Many of his works, such as Kitab al-bukhala’ (The Book of Misers), are highly satirical: Al-Jahiz provided social criticism of his time. In fact, he frequently mixed anecdotes, jokes, and other tales into his writing, which did not set well with some of his learned contemporaries. But al-Jahiz refused to become predictable or boring, and he also believed that a lighthearted approach would attract more readers. Apparently, critics notwithstanding, it worked: He became so well known during his lifetime that he was able to maintain some control over the copying and publishing of his books. This alone was a milestone on the road to the recognition and attribution of individual authorship.

The Book of Animals, in which ninth-century scholar al-Jahiz made the earliest known connections between food consumption and the environment, noting that the environment contributed to the physical characteristics and distribution of plants and animals. (Universal History Archive/UIG via Getty Images)

How did al-Jahiz acquire his diverse and deep knowledge at a time when knowledge about the world was not easily obtained? Al-Jahiz did not refer to himself as a geographer, but many of his writings (in particular, the Book of Animals) are filled with elements of cultural and physical geography. Like many other geographers, he was incredibly inquisitive at an early age, devouring books and manuscripts. In his case, the manuscripts and books covered Arabic poetry and philology, pre-Islamic Arab and Persian history, the Qur’an and the Hadiths, and Greek science and philosophy. Also similar to other geographers, he followed his own unique pathway into research and communicating the results of that research. Apparently, he held no official post, in a government or as a teacher, or even any regular employment, as far as it can be determined from biographers of that time. How did he support himself? Sources indicate that he received money for dedications of books that he wrote, and for a time at least, he received an allowance by the diwan, the finance department of the regional governing body. Like many other geographers (see Hipparchus), he was a prolific writer; one catalog lists 200 titles of his, of which 30 completely survive, with 50 partially preserved.

He eventually went to Baghdad and to Sāmarrā, Iraq, after it became the capital of the Abbasid Caliphate. In each city he found a rich treasure of learning, both in the form of the people there and in the books and manuscripts. Baghdad was a natural place for him to live, because at the time, the Abbasid Caliphate there was actively encouraging scientists and scholars, having just founded the House of Wisdom. This center of learning was multicultural and multi-spiritual, including Jewish, Christian, and Islamic scholars, who made significant advancements in science, mathematics, astronomy, medicine, chemistry, zoology, geography, and cartography; at its time, it was the largest repository of books in the world.

In interviewing people and studying the manuscripts, al-Jahiz broadened his learning and was supervised by the Mu’tazia, a school of Islamic theology based on reason and rational thought that flourished in Iraq for 200 years beginning in the 700s CE. The House of Wisdom became known as a center of learning. Universities, as they are known today, did not yet exist; rather, knowledge was transmitted directly from teacher to student, without any institutional surroundings or structure. But 200 years later, in 1065, al-Nizamiyya was established, one of the first universities and described as the largest university of the medieval world. While al-Jahiz might not have traveled extensively, Basra at the time of his childhood had strong economic ties with Turkestan, India, and the Indian Ocean. And the Abbasid Caliphate during his lifetime provided a rich crossroads, as its greatest extent (in 850) stretched from Tunisia on the west to Afghanistan on the east, including eastern Turkey on the north to Yemen on the south.

Much of his influence stems from his work in zoology. For example, he discovered how to obtain ammonium chloride from animal offal (organ meats) by dry distillation. After studying animals for many years, al-Jahiz put forward his view of biological evolution in his eight-volume Book of Animals. In the book, he set the stage for many tenets of evolutionary theory, including adaptation, animal psychology, sociology, animal embryology, and a scientific classification method. He used a linear classification system for animals, beginning with the simplest and moving on to the most complex, and he arranged them into groups based on similarities. These groups were subdivided to ultimately provide the base unit in each species.

As important to geography as these tenets were, perhaps even more important were his discovery and recognition of the effects of environmental factors on the lives of animals. He linked food consumption and the environment, noting that the environment established or even contributed to the physical characteristics of plants and animals.

Even more forward-thinking are his descriptions of the struggle that all species face. For him, three mechanisms were important: the struggle for existence, the transformation of species into other species, and environmental factors such as food, climate, and shelter. A lower death rate for certain species guarantees that they are better adapted and will survive. For al-Jahiz, the struggle for existence was a divine law and was the natural order of things: God made food for some bodies out of the death of another body. For example, he states, “The rat goes out for collecting his food, and it searches and seizes them. It eats some other inferior animals, like small animals and small birds . . . it hides its babies in disguised underground tunnels for protecting them and himself against the attack of the snakes and of the birds. Snakes like eating rats very much. As for the snakes, they defend themselves from the danger of the beavers and hyenas; which are more powerful than themselves. The hyena can frighten the fox, and the latter frightens all the animals which are inferior to it” (al-Jahiz, translated by R. B. Serjeant, 2000). In other words, al-Jahiz was saying that bigger animals eat smaller animals, and in the struggle for existence, the strongest survive. For al-Jahiz, the first cause of evolution in living organisms was God; the other factors were secondary. For the Greek philosophers and scientists, change occurred, but not in the evolutionary sense. For Lamarck, Darwin, and others, evolution was a natural process devoid of any hand of a creator.

Through his biological evolutionary thoughts, al-Jahiz influenced other doctrines in later Islamic thought—for example, those that concerned sociological, metaphysical, and cosmological evolution. His works were translated into Latin and made their way into the West.

After 50 years of living in Baghdad, al-Jahiz moved back to his hometown, Basra, with a paralysis called hemiplegia. One popular theory is that one of the large piles of books in his private library fell on him to end his life, but it is more likely that, at age 93, he died of natural causes or perhaps from his hemiplegia. Whatever happened to the wonderfully named House of Wisdom? It was destroyed in a Mongol siege in 1258. But the influence of many who studied there, including al-Jahiz, lived on long afterward.

Al-Jahiz’s connections between food consumption, the environment, and evolution had a deep influence on geography. These connections can be seen centuries later in the writings of Marsh and Sauer (see Marsh, George Perkins; Sauer, Carl O.). His thesis that the environment established or even contributed to the physical characteristics of plants and animals was far ahead of its time.

See also: Marsh, George Perkins; Sauer, Carl O.

ANAXIMANDER

The First Map of the World

Anaximander (ca. 610–546 BCE) was a Greek philosopher who lived in Miletus, a city of Ionia (in modern-day Turkey). He was an early proponent of science, as he attempted to observe nature and explain that it is ruled by laws, and that anything that disturbs the balance of nature does not last long. In fact, he was the first to write his treatises in prose, called, traditionally, On Nature. Although only one fragment of the book still exists, it is generally acknowledged that Anaximander had a great influence on philosophy, biology, astronomy, and geography. His principle of the “boundless” (apeiron) as the origin of all things would influence thought through the present time. The “boundless” has no origin, because it is itself the origin. Creation and decay never stop, and the “boundless” has to guarantee the continuation of this process, similar to a free- and ever-flowing fountain.

Anaximander reintroduced the gnomon, the part of the sundial that casts the shadow. He knew about the device from his studies in astronomy; it was invented hundreds of years before by the Babylonians. This was as revolutionary to geography as the map, because the gnomon helped sea captains and others to tell time, thereby helping them to determine their location. Basing his claim on fossil evidence, he argued that animals sprang out of the oceans long ago. Cicero, writing 500 years later, stated that Anaximander had predicted an earthquake for Lacedaemon, a Greek city-state, convincing the inhabitants to evacuate, and that Anaximander was vindicated when an earthquake actually did take place.

Anaximander subscribed to the Greek philosophy that there were four basic elements of nature: water, air, fire, and earth. He took this one step farther by stating that these elements were symmetrical and transferrable. He explained how they were formed, and how Earth, people, and animals were formed through their interactions. He was the first to conceive of a mechanical model of the Earth, and although he incorrectly placed the Earth at the center of the universe, his use of explanatory hypotheses that were not based on myths was a great leap forward in thought. His model showed the Earth floating freely without falling, and not needing to be resting on something. This allowed the sun, the moon, the planets, and the stars to pass under or behind the Earth, opening the way to Greek astronomy. He also was the first astronomer to consider the sun as a huge mass a long distance from the Earth, and he was the first to present a model in which the celestial bodies turned at different distances. Anaximander believed that the celestial bodies made full circles. This could not have been observed for every celestial body; rather, it was a conclusion that he drew, and certainly it was a daring and bold one for its time or for centuries afterward. Thus, he was the very first philosopher who imagined a bold new concept: space. Space had depth; it was three-dimensional; celestial bodies occupied that space. These bodies therefore could be in front of or behind one another. Moreover, Earth occupied that space. All of this was a radical break from the prevailing idea that held that the sun, the planets, comets, and the stars were attached to a dome or tent, all at the same distance from the Earth. His model of space placed the stars nearest to Earth, followed by the moon and then the sun. The celestial bodies operated on something like chariot wheels, with openings that opened and closed, allowing us to see parts of all of them. He thought of the Earth as a sort of cylinder. Although these notions are obviously erroneous, the idea that the Earth was hanging free and unsupported in space was revolutionary. It was not actually observed until the first astronauts of the 20th century saw this with their own eyes.

Anaximander did not just issue statements; he gave arguments. This is why most consider him to be the first true philosopher. His ideas influenced modern philosophers such as Friedrich Nietzsche in the 19th century.

Even more than his concept of space, Anaximander’s most revolutionary contribution to the discipline of geography was through his map. It wasn’t just a map of Miletus: Strabo and Agathemerus, later Greek geographers, both claim that according to Eratosthenes, Anaximander was the first person to publish a map of the world. The map most likely showed the world known to the Greeks at the time—the Middle East, the area east and north of the Black Sea, north and northeastern Africa, and central and southern Europe.

Anaximander’s map. His notion that the Earth and celestial bodies exist in three-dimensional space, and his insistence on measuring and explaining, were revolutionary. (Chronicle/Alamy Stock Photo)

The map may have been designed on a slightly rounded metal service, and most likely with Delphi or Miletus at its center. The Aegean Sea was near the map’s center, and the map included the three known continents—Europe, Asia, and Africa—separated by the known lakes, seas, and rivers of the time. Separating Asia from Europe were the Aegean Sea, the Black Sea, and a river now known as the Rioni, which originates in Georgia’s Caucasus Mountains and flows west to the Black Sea. Separating Europe from Africa was the Mediterranean Sea. Separating Africa and Asia was the Nile River, which, according to the map, flowed south to the ocean (its true flow is north, to the Mediterranean Sea). Libya was the name given to Africa at the time. The habitable world (Greek oikoumenê) was on either side of the Mediterranean Sea; north of this zone, it was too cold, and south of it, too hot. Surrounding the continents on his world map, on their outer margins, was a single connected ocean.

Thus, the continents on Anaximander’s map were shown to be surrounded by water—in itself a revolutionary map element. Anaximander may have drawn his map to improve navigation between the colonies of Miletus and other colonies. The map also may have been drawn for Thales, his contemporary, to convince Ionian city-states to join a federation to push away the threat from the Medes of Persia. But given the philosophical environment that was emerging among the Greeks at the time, it is just as likely that he produced the map for the sheer love of learning and for the advancement of science.

Anaximander’s map most likely inspired the Greek historian Hecataeus of Miletus to construct a more detailed and accurate map. Anaximander’s contributions moved geography forward in several significant ways. In fact, Strabo viewed Anaximander and Hecataeus as the first geographers after Homer (see Strabo; Homer). How did Anaximander produce such an important map? One explanation is that he hailed from Miletus, a place known for its bold sailors. Therefore, like other geographers and cartographers, he is likely to have been a well-traveled man. This fits with the notion that geography has long been strengthened by travel and careful observations.

See also: Eratosthenes; Homer; Strabo

ANTARCTICA

To the End of the Earth

The term referring to the opposite of the Arctic Circle, “Antarctic,” was first spoken by Marinus of Tyre in the second century BCE. For millennia, a continent lying in the far south of the globe, Terra Australis, was believed to exist long before any human ever set eyes on it. The rounding of the Cape of Good Hope and Cape Horn in the 15th and 16th centuries by Bartolomeu Dias and Magellan showed that if Terra Australis existed, Antarctica would be its own continent (see Magellan, Ferdinand). However, this suspicion was not confirmed overnight. Indeed, Magellan thought that Tierra del Fuego’s islands were an extension of the southern continent, and Papua New Guinea was thought to connect to the southern continent. Eventually, Francis Drake began speculating that an open channel south of Tierra del Fuego must exist. In 1615, Schouten and Le Maire discovered the southern end point of Tierra del Fuego, which they named Cape Horn. A generation later, in 1642, the explorer Tasman showed that New Holland, or Australia, was separated by sea from any continent that might exist farther south.

Even so, a predominant school of thought maintained that most of the higher latitudes in the southern hemisphere was covered by a continent that must be massive in size. James Cook’s second voyage, from 1772 to 1775, changed all of that: He proved that no such large landmass existed, although the large ice floes he observed made him hypothesize that some sort of continent must exist. Moreover, Cook’s voyages conclusively demonstrated that the unknown lands were not the hoped-for “fertile lands” but instead were almost assuredly hostile. These discoveries caused a shift in emphasis during the first part of the 1800s, away from trade and toward discovery and exploration.

French naval officer Jean-Baptiste Charles Bouvet de Lozier reached 55° South in 1730. During the years 1773 and 1774, James Cook and his crew were the first to cross the Antarctic Circle. They discovered islands nearby and came to perhaps 150 miles (241 km) from Antarctica, reaching 71°10' South, after which time ice impeded their further progress. This southern record would hold for another 49 years. Political geography encouraged the subsequent period of exploration in the early 1800s as Europe went through a relative peace. An expedition led by Russia’s von Bellingshausen and Lazarev, another expedition led by the British captain Bransfield, and a third expedition led by Palmer, an American sealer, all claimed to have seen the ice shelf or the Antarctic continent in 1820. However, the first landing on the continent probably took place at the moment when the American captain John Davis, a sealer, set his foot on the ice shelf on February 7, 1821. In 1823, the British sealer James Weddell sailed into what is now known as the Weddell Sea.

In 1840, Charles Wilkes, a commander in the U.S. Navy, discovered what is now known as Wilkes Land. This land lies at around 120 East longitude. Following the discovery of the North Magnetic Pole in 1831, explorers and scientists searched earnestly for its equivalent in the south, the South Magnetic Pole. British naval officer James Clark Ross identified its approximate location in 1841 (see Magnetic Field). The first documented landing on the Antarctic mainland occurred on what is now known as Victoria Land. This landing was by Mercator Cooper, an American sealer, on January 26, 1853. The explorations that followed began to form a line, though broken in many places, of lands along the coastline of Antarctica. These explorations were unable to penetrate the interior, resulting in a 20-year period of disinterest; Ross even suggested in 1841 that there were no scientific discoveries worth exploring any further.

Despite Ross’s recommendation and the subsequent lull, suddenly there came a fury: The “Heroic Age of Antarctic Exploration” began at the close of the 19th century and ended with the survivors of the Shackleton expedition stepping ashore in New Zealand on February 9, 1917 (though some consider 1945 as the closing date for intense exploration). During this period, an international effort from 10 countries resulted in 17 major Antarctic scientific and geographical expeditions. The geographical South Pole was reached and much coastline and interior mapped and explored, generating large quantities of scientific data and specimens across many disciplines but with much focus on geography.

The final sinking of Shackleton’s ship Endurance after being trapped by ice for 10 months, on November 21, 1915. Shackleton and other Antarctic explorers expanded the knowledge of physical geography of the southernmost oceans and continent, and also advanced knowledge of the Earth as a system. They fostered public affinity for adventure and exploration through land and sea voyages to Earth’s last great unknown area. (Library of Congress)

The renewal of interest was tied to an 1893 speech in which Dr. John Murray advocated to the Royal Geographical Society in London that Antarctic research “resolve the outstanding geographical questions still posed in the south” (Crane 2005) (see Geographical Societies). A German scientist, von Neumayer, advocated meteorological research as leading to more accurate weather predictions. In 1895, the Sixth International Geographical Congress in London passed a general resolution calling on scientific societies throughout the world to promote the cause of Antarctic exploration “in whatever ways seem to them most effective.” Such work would “bring additions to almost every branch of science,” and indeed, that is what it accomplished. The Belgian Geographical Society’s 1897 expedition became the first to overwinter within the Antarctic Circle. The following winter, the British Antarctic expedition was the first to overwinter on the mainland, recorded the position of the South Magnetic Pole, ascended the great ice barrier, and reached 78°30’ South latitude.

Overwintering gave confidence that the South Pole could be reached: Scott’s 1901–1904 expedition, those of Australia and New Zealand, those of Gauss and Charcot, and that of Japan’s Kainan Maru studied new territory. Yet it was the “race for the Pole” that captured the public’s attention. A rivalry began between Robert Falcon Scott from England and Ernest Shackleton from Ireland. The efforts of Shackleton fell short, but Scott was successful in reaching the South Pole in January 1912. To his dismay, he found that he had been narrowly beaten to the site by Norwegian explorer Roald Amundsen, who had reached it about a month before, on December 14, 1911. Geography played a role here as well: Amundsen’s party had discovered a new route to the plateau upon which the South Pole stands, by accessing the Axel Heiberg Glacier. And Scott’s first time at the Pole was to be his last: After reaching the Pole via the Beardmore route on January 17, 1912, 33 days after Amundsen, he and his four companions died of starvation and cold on the return journey.

Ernest Shackleton led four British expeditions to the Antarctic. The first was on Scott’s expedition of 1901–1904; the second was from 1907 to 1909, when he and three companions stood on 88° South and climbed the volcano Mount Erebus. His intended third expedition was to cross Antarctica from sea to sea, via the Pole, in 1914–1917. But disaster struck when his ship Endurance was crushed by pack ice, and after floating to Elephant Island, Shackleton and a few men made it across a stormy ocean 820 miles to the island of Georgia. He eventually rescued nearly his entire crew. He returned to the region in 1921 but died of a heart attack while at South Georgia Island.

After Scott left the South Pole in January 1912, it remained unvisited for nearly 18 years, and when the next visit occurred, it wasn’t on foot: U.S. Navy commander Richard E. Byrd and three of his companions completed the first aircraft flight over the South Pole in 1929. Rear Admiral Dufek stood on the Pole in 1956 after landing their airplane nearby. Vivian Fuchs led the Commonwealth Trans-Antarctic Expedition and reached the South Pole on January 19, 1958, becoming the first team to arrive at the Pole using the overland route since Scott’s 1912 visit. In February 1957, a permanent South Pole research station was erected, named the Amundsen–Scott South Pole Station in the explorers’ honor, housing up to 150 scientific staff and personnel (see Observatories). Approximately 30 countries’ governments maintain widely distributed, permanent research stations in Antarctica, on rock or on very slowly moving ice; the population ranges from 1,000 in winter to 4,000 in summer (December), with 30 summer field camps.

Why was the quest to explore Antarctica revolutionary to geography? Even though the quest for the North Pole was occurring simultaneously, the South Pole was more remote and more easily romanticized. Many expeditions resulted in gruesome injury such as frostbite; the result for 19 explorers was death. Each expedition became a feat of physical and mental endurance; the protagonists were flawed, and competition was fierce. After his share in the Discovery Expedition, Shackleton suffered a physical collapse on the return; Scott sent him sent home. The two became rivals, prompting Shackleton to organize his own polar venture, the Nimrod Expedition.

The characters remain compelling to the present day. Shackleton, for example, has eclipsed Scott in respect, and he is held up as a model of corporate leadership. Controversy continues as to whether Scott was a hero or just keen on self-promotion. For 75 years, Scott was almost universally venerated because most recognized that his team had hauled its own sledges, while Amundsen’s team skied and used dogs. The implication was that Scott had somehow done it the right way. It wasn’t until Huntford’s book later in the 20th century (1979) that the prevailing sentiment began to turn. Huntford asked the public to consider whether Scott was self-venerating, even in his final journal entry before he froze. Huntford claimed that Amundsen, who had received little credit, was the real hero: It was Amundsen who brought his men back safely. On the other hand, Scott was interested in collecting data and perhaps was the “real geographer” of the two. In the final analysis, surely they both had weaknesses but many strengths.

Furthermore, before World War I, national honor was at stake. In one appeal to British patriotism, Sir John Murray asked, “Is the last great piece of maritime exploration on the surface of our Earth to be undertaken by Britons, or is it to be left to those who may be destined to succeed or supplant us on the Ocean?” According to Griffiths (2010), “It was the site of Europe’s last gasp before it tore itself apart in the Great War.” The explorers were heroes to their nations and contributed to poetry and art, such as Shackleton’s A Tale of the Sea (1901):

Where nailed to the rotting flagstaffs:

The old white Ensigns flew

Badge of our English freedom

Over all waters blue.

While exploration in the mid-20th century continued with the exploration of Everest and other peaks, followed by space voyages, voyages to Antarctica were the last major land and sea journeys of the type that had begun in the 1400s with Bartolomeu Dias and Christopher Columbus. While the Antarctic expeditions lacked social media feeds, telegraphs and newspapers brought the explorers’ stories before the public more quickly and with greater detail than ever before.

Another reason the exploration was revolutionary was that people were realizing that Antarctica was not going to be colonized like the other continents had been. The competition was therefore on scientific grounds; this was something new, though its roots could be argued as beginning with the French geodesic survey of the early 1700s (see French Geodesic Mission). Antarctic exploration connected key pieces of geographic knowledge about the Earth that helped geographers more fully grasp it as a system, eventually leading to the International Geophysical Year (see International Geophysical Year), the discovery of the link between chlorofluorocarbons and ozone, the connection between Antarctic ice and ocean currents and climate change, and much more.

Ann Bancroft

Ann Bancroft (born 1955) became the first woman to cross both polar ice caps to stand on the North and South poles. She arrived at the North Pole in 1986 after a 56-day expedition with five others; seven years later, she led a four-woman expedition to the South Pole. She also is the first woman to ski across Greenland, and in 2001, she and Liv Arnesen skied across the entire continent of Antarctica. To devote time to her explorations, she gave up her job as a wilderness instructor and gym teacher in Minnesota, but she continues to be active in educating all ages about geography and exploration. At the 1998 GeoTech Conference in Dallas, when describing her ski trip to the South Pole in whiteout conditions, she very humbly said that she “just followed the GPS receiver’s ‘Go To’ arrow pointing due south.”

(Quote from GeoTech Conference, 1998, as noted by Joseph Kerski)

In 2001, Ann Bancroft and Liv Arnesen became the first women to ski across Antarctica. In 2011, Christian Eide set a world record of skiing unassisted from the coast to the South Pole—24 days, 1 hour, 13 minutes. Thus, for some, the Antarctic is still the ultimate challenge.

See also: Cook, James; French Geodesic Mission; Geographical Societies; International Geophysical Year; Magellan, Ferdinand; Magnetic Field; Observatories

APPLIED GEOGRAPHY

Solving the World’s Problems

Geography has a long-established reputation as a discipline with relevance to the “real world.” The geographer’s focus on space and place, and on issues relevant to 21st century society, make geography inherently an applied discipline.

Geography assigns itself the most vexing and complex problems and challenges facing societies around the world, including political instability, crime, natural hazards, water quality and quantity, food security, agricultural sustainability, climate change, renewable energy, efficient transportation, human health, healthy economies, social justice, and many others. The underlying rationale of applied geography is that only through a clear understanding of the relevant societal, physical, and coupled natural and human systems can humans resolve these challenges. Geographers believe that all of these challenges share one thing in common—they all occur somewhere, and they have specific spatial patterns, relationships, and trends that can be best understood through the perspective of geography. The subtitle of the Applied Geography journal encapsulates this notion: “Putting the World’s Human and Physical Resource Problems in a Geographical Perspective.” Paccione (1999) defined applied geography as “the application of geographic knowledge and skills to the resolution of social, economic, and environmental problems.” Paccione also suggested that applied approaches are either (1) studies of a specific problem occurring over a small part of the Earth, such as tracing the diffusion of pollutants through a water channel, or (2) studies of a major issue occurring over a large part of the Earth, such as ways to model climate change and the implications of these models. He advocated a “DEEP” procedure: description, explanation, evaluation, prescription, implementation, and monitoring.

Finding the optimal site to locate a freeway such as this one in Florida, with minimal environmental impact, is accomplished through the application of geographic principles and geotechnologies. Over the past century, geography has become much more specialized, resulting in its application to a greater number of problems and challenges than ever before. (Joseph Kerski)

Furthermore, all of the world’s challenges occur at specific scales and perhaps not at other scales, they are interconnected in time and space, they change over time and space, and they affect human populations and are in turn affected by human populations. All of these themes are fundamental to geography, and hence, geographers seek to apply their discipline’s skills, content knowledge, and perspectives to these issues. As time passes, these issues grow in complexity and, in some cases, severity; and as the world becomes increasingly connected socially and economically, these issues increasingly impact people’s everyday lives. As the recognition of this grows, as awareness of environmental and related issues grows (see Environmental Movement), and as more people regularly use tools created by geographers (such as Web-based mapping), geography is applied to more problems and issues with each passing year. For example, geography is regularly applied to determine which businesses should operate on a city street, how governments should make energy and trade agreements, and how to develop the most efficient and attractive light rail lines through a city and the adjacent residential and commercial lands.

Applied geography is nothing new to geography; indeed, beginning with Eratosthenes determining the size and shape of the Earth, many of the chapters in this book describe problems that geographers have addressed, such as navigating the ocean, determining longitude, building canals and railroads, predicting the weather, subdividing land for human settlement, or even generating energy or fighting battles (see Eratosthenes; Harrison, John).

In academia, despite some applied geography threaded through higher education, geography was oriented largely to teaching until the mid-20th century. At this time, pressures mounted for universities to address more specifically the needs of society through undertaking applied research for the public and private sectors. The increasing complexity of modern life, along with the increasing specialization of disciplines, including geography, caused a great increase in research and development around applied geography. The notion of applied geography is sometimes associated with activism in geography, but even if not, there is a sense that there is a potential user, or client, of the knowledge that geographers impart. The “value” of applied geography is tied to its relevance or utility, and geographers consider such topics as “Who decides what is useful?” and “What are the criteria for deciding what is useful?” These questions are related to values and ultimately to cultural considerations.

One example of the recognition of the applied nature of geography has been the existence of the Office of the Geographer at the U.S. State Department for much of the 20th Century. Other examples of applied geography have even achieved some notoriety outside geography over the past century. Probably the most widespread application of geography is through the use of GIS and remote sensing technologies (see Geographic Information Systems; Remote Sensing). The annual conference hosted by the GIS software company Esri, for example, grew from 12 people in 1984 to 16,000 people by 2015. Worldwide, 350,000 organizations, including two-thirds of Fortune 500 companies, apply geography using Esri technology on a regular basis. The application areas continued to expand, from city planning and natural resource management during the 1980s to just about every major field by 2000, including public safety, natural hazards, human health, water quality, energy, and human behavior.

Gilbert F. White was a prominent American geographer that well exemplified this applied and practical nature of geography. Sometimes called “the father of floodplain management,” he specialized in natural hazards and the importance of sound water management in contemporary society. Often critical of government policy about flooding, he argued that public confidence in structural works such as levees increased human occupancy on floodplains and increased damage by flooding, rather than decreasing them. As such, he advocated more use of arrangements by a governing body to restrict the use of floodplains and human adjustments to flood risk that do not involve substantial investments in flood controls (Wescoat and White 2003).

As the number of people graduating from institutions of higher education greatly expanded during the 20th century, as the available job positions for subject generalists failed to keep pace with the number of people looking for work, and as tools, data, and methods increased the manner in which geography could be studied and applied, there was a great increase in specialization in geography. Even the specializations present at the beginning of the century further subdivided, so that, for example, some population geographers came to examine changes in tenancy of businesses in a single metropolitan area and how those changes reflected broader trends in the regional and national economy and lifestyles. Other population geographers came to model population change through the development and study of the demographic transition theory—how birth rate, death rate, life expectancy, industrialization, and international migration change the demographic makeup of a country or the world over time. Still other population geographers focus on how to estimate population at risk from natural hazards or sea-level change by developing population density maps from remotely sensed imagery and GIS databases, particularly important in countries without a formal census of the population. Indeed, specialization goes hand in hand with applied geography, because a geographer specialized in addressing a specific subfield of geography will seek to apply his or her knowledge to the problems in that subfield.

Ian McHarg

Ian McHarg (1920–2001) made a lifelong contribution not only to geography, but also to urban planning, landscape architecture, and the development of GIS. His influential 1969 book Design With Nature pushed for landscape planners to conform to, not compete with, ecological principles. He founded the University of Pennsylvania’s department of landscape architecture and regional planning and worked there for 30 years, influencing numerous students and colleagues with his message that no human action should advance without studying the suitability for the area’s vegetation, topography, hydrology, wildlife, and other criteria. His assessment method centered on a “layer cake” of stacked transparent maps on sheets of Mylar, foreshadowing modern map overlay techniques within a GIS. His book To Heal the Earth, written a few years before he died, is a title reflecting his view of humans’ role in the natural system.

Specialization certainly was not unique to geography: Virtually every other scientific and non-scientific discipline saw increasing specialization during the 20th Century. But with specialization in geography, many geographers began to voice the concern that specialization endangered one of the most valuable things that geography brings to the academy—the ability to view the world holistically, as a system. Geographers are concerned with how the ecosphere, geosphere, hydrosphere, atmosphere, and anthrosphere (human element) are interconnected. As the 21st century dawned, it came to be acknowledged that specialization brought vital insights to the discipline and to society, but geographers also needed to keep the core tenets of the discipline in mind in their research; in other words, not getting too “lost in the weeds” of the details. The caution was thus on over-specialization to the exclusion of the “Earth view” that geography has always valued.

See also: Environmental Movement; Eratosthenes; Geographic Information Systems (GIS); Harrison, John; Remote Sensing

ARYABHATA AND BRAHMAGUPTA

Using Mathematics to Explain Geography

Mathematics is fundamental to geography. Much of geography has to do with measurement, spatial statistics, and other forms of quantitative analysis—the size and shape of the Earth, scope of land cover or population change over space and time, volume of trade or social media, or clustering of crimes in a community, to give but a few examples. Without mathematics, geographers would be severely hindered in understanding the planet and its complex systems and interactions. Without mathematics, many geographic tools would not exist—GPS, GIS, remote sensing, or even maps themselves. Without mathematics, the quantitative revolution never could have happened (see Quantitative Revolution). Therefore, it should come as no surprise that some of the revolutionary moments in geography have come from mathematicians.

Several revolutionary moments in geography occurred from the work done by Aryabhata and Brahmagupta, who personify the mathematical innovations occurring in India between 400 and 700 CE, the “classical era” of Indian mathematics. Aryabhata the Elder, or Aryabhata I (476–550) may have been born near present-day Patna in northeast India, not far from the southern border of Nepal. His book Aryabhatiya was written when he was only 23 years old, in 499, and is a collection of 108 poetic verses in the sutra style of the period, in which each line is an aid to memorization. The book contains four pādas, or chapters.

In his book, Aryabhata calculated the Earth’s circumference to be 4,967 yojanas, or 24,834.96 miles (39,968 km)—within 99.8 percent of the accepted modern figure of 24,901.45 miles (40,075 km). He also computed the length of the year accurately—to within 12 minutes and 30 seconds. He recognized that the Earth was a sphere and that it rotated daily, going against the prevailing notion of that time, when most people believed that the sky rotated. He championed the idea of measuring the beginning each day at midnight. He correctly described the orbits of the planets as ellipses, though, like Ptolemy, he also used epicycles to explain motions. He correctly explained why equinoxes, solstices, and eclipses occur. He also calculated pi (π) to four decimal places; this alone enabled him to make accurate estimations of the size of the Earth and of Earth-sun relationships. Thus he was an early and key visionary who saw the tie between mathematics, geography, and astronomy. He correctly stated that the moon and planets shine by reflected sunlight. He described astronomical instruments, including those that measured shadows and angles, as well as clocks (see Cross-Staffs, Astrolabes, and Other Devices; Harrison, John).

Statue of Aryabhata on the grounds of the Inter-University Centre for Astronomy and Astrophysics in Pune, Maharashtra, India. Aryabhata and Brahmagupta were scientists from India who, 1,500 years ago, made enormous advances in mathematics, geography, and astronomy. (Dinodia Photos/Alamy Stock Photo)

Aryabhata helped to ignite a new era in mathematics, particularly by his introduction of the concept of trigonometry. His work in mathematics spurred innovation and development in other sciences not only by himself, but also by others, in geography and astronomy. His definitions of sine, cosine, versine, and inverse sine were so influential that they influenced a new field to begin: trigonometry. He believed in scientific investigation and, to that end, founded research facilities; these centers were instrumental in the training of future scientists.

Aryabhata’s contributions were not the first that Indian mathematicians had made—indeed, Indian mathematicians contributed some of the most important concepts of all, such as numerals—a vast improvement over Roman numerals. The Indian system allowed for computation to be done much more conveniently and briefly; Hindu arithmetic used number symbols only from 1 to 9, with place-values for higher numbers and a physical alignment of tens, hundreds, and so on. A bit later, Indian mathematics also contributed the decimal system based on powers of ten, positive and negative signs, and methods for solving quadratic equations. These and other techniques helped make modern science and technology possible. Some of these techniques were written down by Muhammad ibn Musa al-Khwarizmi, a teacher in the mathematical school at Baghdad. His book was translated into Latin as Algoritmi, from which came the word “algorithm,” and from his book on mathematics Kitab al-jabr wa al-muqabalah came the word “algebra.” Because these Indian symbols were introduced to the Western world by Muslim mathematicians from the Middle East, they came to be known as Arabic numerals.

Like other revolutionary moments and people described in this book (e.g., see Wegener, Alfred), many of the Earth-sun relationship concepts that Aryabhata set forth were not accepted during his lifetime. However, Aryabhata the Elder’s impact on geography was revolutionary. Beyond his contribution to fundamental Earth measurements and to mathematics, however, was his contribution to scientific thought and methods. In a time and place where folklore and superstition were commonplace, his book was a major step forward in separating these elements of society from scientific explanation. Because of his work, his book Aryabhatiya held the same stature in India that Euclid’s Elements did in ancient Greece. In India, his ideas spelled the end of the period of the Sulvasutras, during which mathematics was used primarily by priests for temple architecture. Thus he helped make science and mathematics understandable, and many more scholars were able to contribute to them.

One of those whom Aryabhata influenced was the Hindu astronomer and mathematician Brahmagupta (598–670). Brahmagupta served as head of the innovative Ujjain astronomical observatory, which was to India as important as the Royal Observatory in Greenwich was to Western Europe—a center of astronomy and mathematics. There, he investigated the motions of planets and other celestial bodies, arriving at an amazingly accurate estimate of the length of the terrestrial year: 365 days, 6 hours, 12 minutes, and 36 seconds (today’s accepted value is 365 days, 5 hours, 48 minutes, and 46 seconds). His most important contributions are the introduction of the number zero to mathematics. His magnum opus, written when he was 30, sports a wonderful title, the Brahma Sphuta Siddhanta (“The Opening of the Universe”). He is considered to be the first person of his time to use mathematical (and in particular, algebraic) techniques to predict astronomical phenomena such as planetary motions and eclipses. Like geographers and astronomers over 1,000 years later, he showed how motions could be described in advance of their actual occurrence. Thus, like the events he was predicting, he was far ahead of his time.

Brahmagupta’s book was used to introduce the basic ideas of algebra to Islamic mathematicians, who combined their original contributions with Brahmagupta’s work, furthering advancements in mathematics that have impacted geography to the present day. One of his contemporaries, Bhaksara II, called him Ganita Chakra Chudamani—“the gem in the circle of mathematicians.”

Brahmagupta was instrumental in introducing and working with the concept and number zero. As an educator, he also introduced new methods and story problems for solving quadratic equations and other mathematical problems that would be recognizable to modern students; for example, “Five hundred drammas were loaned at an unknown rate of interest. The interest on the money for four months was loaned to another at the same rate of interest and amounted in ten months to 78 drammas. Give the rate of interest” (Brahmagupta 628).

India’s first satellite and a lunar crater are named in Aryabhata’s honor. The calculations that Aryabhata and Brahmagupta used were all the more remarkable because they were derived entirely by mathematics—they had no scientific instruments in the modern sense, not even an ancient telescope. Though they did not call themselves geographers, Aryabhata and Brahmagupta had a great influence on geography through their innovations in mathematics, on Earth-sun relationships, and on the scientific method. One hundred years after Aryabhata, Bhaskara I wrote, “Aryabhata is the master who, after reaching the furthest shores and plumbing the inmost depths of the sea of ultimate knowledge of mathematics, kinematics and spherics, handed over the three sciences to the learned world” (Keller 2006).

By bringing together the disciplines of mathematics and other sciences with geography, Aryabhata and Brahmagupta had a long-lasting influence on all of these disciplines. They foreshadowed the discipline-bridging that geographers hundreds of years later would attempt (e.g., see Arlinghaus and Kerski 2013).

See also: Cross-Staffs, Astrolabes, and Other Devices; Harrison, John; Quantitative Revolution; Wegener, Alfred

ATMOSPHERIC RESEARCH

Understanding What’s Above

Because the atmosphere is so important to life on Earth and is so intertwined with the core topics that geographers study (such as ocean currents, climate, weather, pollution, agriculture, ecoregions, erosion, Earth-sun relationships, and much more), advancements in the study of geography and the study of the atmosphere have gone hand in hand.

Consider cirrus clouds, for example. These clouds typically cover nearly a third of the globe and are found high in the atmosphere—5 to 10 miles (8–16 km) above the surface. A new study (Cziczo 2013) showed that despite their height, they typically have a core that is tied to the Earth, namely, dust and metallic particles in addition to the ice crystals that they have long been known to be made of. Cirrus clouds are important to global climate because they interact with radiation from the sun and from the Earth. The study, like many concerning the atmosphere, has a human-environment theme (see Defining Geography): Could human agricultural practices, mining, and industrial processes, or desertification cause more dust to enter the higher atmosphere? If so, could this impact the amount of cirrus cloud formation, and if so, what are the implications for climate?

Atmospheric science is made up of meteorology, climatology, atmospheric chemistry, and atmospheric physics. Research topics include weather, climate, environmental impacts of climate, pollution, air chemistry, sun and space weather (see Magnetic Field), and other key components of the Earth system. But the human element is also important, including the societal and other effects of weather and climate on human populations.

Cumulus clouds over the Mojave Desert in California. Because the atmosphere is so important to life on Earth, and is so intertwined with the core topics that geographers study, such as ocean currents, climate, weather, pollution, agriculture, ecoregions, erosion, Earth-sun relationships, and much more, advancements in the study of geography and the study of the atmosphere have gone hand in hand. (Joseph Kerski)

Atmospheric science, like geography, has been revolutionized by probes, satellites, and field equipment. For example, in the cirrus cloud study described above, instruments aboard a high-altitude research aircraft selectively captured ice crystals from the clouds, and the PALMS (Particle Analysis by Laser Mass Spectrometry, developed by NOAA) instrument was used to analyze the residual tiny seed core and its chemical composition. Another frequently used device in atmospheric science is the high-altitude balloon, first used in the late 1800s and continuing through to today. In fact, Léon Teisserenc de Bort (1855–1913), a pioneer in atmospheric science who discovered the tropopause and was a co-discoverer of the stratosphere (with Richard Assman), was also an innovator in designing and testing research weather balloons. Richard Assman also was involved in probes and instrumentation: He developed a psychrometer for measuring atmospheric humidity and temperature while shielded from solar radiation. The first weather satellite considered successful was TIROS-1, operating for 78 days in 1960. Today, a myriad of weather satellites operating in the visible and infrared parts of the electromagnetic spectrum provide continual coverage of the atmosphere, in geostationary (orbiting above the Equator at the same speed as the Earth below them, such as the GOES and Meteosat series of satellites) and in polar orbiting positions (including the NOAA, Metop, and U.S. Defense Meteorological Satellite Program [DMSP] satellites).

Atmospheric science also has benefited from geographic technologies such as GIS, GPS, and remote sensing. Understanding the atmosphere helped make GPS and remote sensing possible by enabling the physics to be mastered for launching and keeping satellites in orbit. Furthermore, GPS enables the X, Y, and Z positions of each atmospheric observation on the ground and in the air to be mapped and hence the atmospheric layers to be understood. For example, the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) program uses GPS satellites in conjunction with low Earth-orbiting (500 miles or 805 km) satellites to map and analyze the ionosphere. GIS and remote sensing technologies provide sets of spatial concepts, standards, and tools, including spatial statistics, which can be used to explore spatial patterns in meteorological data, climate variability, and change assessment, among other applications. Remote-sensing sensors rely on the different properties of the atmosphere and of shortwave and longwave radiation, and the different reflectivity wavelength response of different land use, vegetation, and other features of the Earth’s surface to allow these features, as well as changes, to be detected. Two MODIS (Moderate Resolution Imaging Spectroradiometer) instruments, launched in 1999 aboard the Terra platform and more in 2002 aboard the Aqua platform, are designed such that they have a wide spectral range, have a fine spatial resolution, and provide global coverage nearly every day. They are used to observe and monitor variables in atmospheric trace gases, cloud cover, cloud type, solar radiation, and tropospheric aerosols, and the changes in those variables.

Geographic information systems provide a platform, with tools, models, and data, for atmospheric analysis. The standardization of geospatial databases and linking the databases together have been invaluable for fostering climate research. This was especially important for climate studies, given the large size of typical atmospheric databases and the fact that they are in three or four (with the inclusion of time) dimensions. These databases, in a GIS environment, have been integrated and made accessible for multiple applications and studies, and they have greatly aided the general public’s understanding of weather and climate through visualizations that are now commonplace on TV and Internet weather programs and in Web maps (see Geographic Information Systems; Global Positioning Systems; Remote Sensing). But perhaps the biggest revolution that GIS has in atmospheric research is the ability to use GIS for building, testing, and modifying climate models, which require hundreds of large, complex data sets and the ability to adjust for thousands of variables.

These models could not have been developed and tested in the days of analog maps on paper and film. Indeed, as GIS has benefited atmospheric science, atmospheric science in turn provides benefits for GIS, well exemplified in the GIS program at the National Center for Atmospheric Research (http://gis.ucar.edu). This program provides important new techniques and application areas for GIS, such as the Climate Inspector, which offers downloadable climate change data and also a new interactive Web application that visualizes possible temperature and precipitation changes throughout the 21st century: in so doing, it makes these tools a standard part of GIS software.

Atmospheric science, like geography, has a strong practical side. For example, the Flood Forecasting Initiative at the World Meteorological Organization (WMO) helps national disaster management authorities around the world prepare and respond to flood hazards when lives and property are at stake. Atmospheric science has also had decades-long ties to citizen science. In education, for example, the Global Learning and Observations to Benefit the Environment (GLOBE) program since 1994 has encouraged students and citizens to collect and analyze data on the atmosphere, biosphere, hydrosphere, and pedosphere (soil). With the advent of humans as sensors and the Internet of Things, rapidly changing phenomena such as atmospheric conditions can be fed instantly to the sensor network, enabling the atmosphere to be monitored as never before (see Internet of Things).

The 1900 Galveston Hurricane

Long before Hurricane Katrina or Superstorm Sandy, the deadliest natural disaster in the history of the United States was the hurricane that made landfall on Galveston Island in early September 1900. Between 6,000 and 12,000 people perished in Galveston, yet the storm was still not done: It capsized a boat far to the north on Lake Michigan, drowning the crew. The Galveston hurricane caused people to begin to have more respect for natural hazards, tearing them away from their complacency of being modern, 20th-century Americans, and helped them realize that no seawall could withstand a Category 4 hurricane. The highest point in Galveston was only 8.7 feet (or 2.7 meters) above sea level—Galveston was itself a barrier island. Nonetheless, everyone in the city could have been evacuated (and no one should have perished) had the warnings been heeded.

The Earth’s atmosphere is composed primarily of nitrogen (just over 78 percent) and oxygen (just under 21 percent) and includes other gases that are small in amount but important. Indeed, during the 20th century, geographers and atmospheric scientists found that many of these, including the “greenhouse gases”—such as carbon dioxide (0.0397 percent), methane, nitrous oxide, and ozone—were critical to supporting the balance of life on Earth. Mapping the atmosphere was a revolution in helping understand the Earth, as it was discovered that the atmosphere contains five distinct layers: the troposphere (0 to 12 km), the stratosphere (12 to 50 km), the mesosphere (50 to 80 km), the thermosphere (80 to 700 km), and the exosphere (700 to 10,000 km).

The location of these layers and the gases within them were found to be important; for example, most of the ozone lies within the stratosphere but plays a key role in absorbing most of the sun’s ultraviolet radiation. With the discovery of the depletion of ozone levels during the 1970s and the presence of chlorofluorocarbons (CFCs) in the upper atmosphere, countries began to ban CFC-containing aerosol sprays, with the result that ozone depletion has slowed significantly. This added additional energy to the environmental movement and lent new emphasis in the scientific community to the importance of seeing the Earth as a system, long a core tenet of geography.

As human population expanded, human use of natural resources increased, mapping technologies became affordable and available, and awareness of environmental issues increased (see Environmental Movement), geographic and atmospheric research has, over time, become even more important to geography and more critical to society. Indeed, an increased understanding of the atmosphere—of which 75 percent of its mass (5.15 × 10¹⁸ kg) is within 36,000 feet (6.8 miles, or 11 km) of the Earth’s surface—has been a significant factor contributing to geographic awareness and activism: People began to realize that this thin layer sustains all life on the planet.

Given the common themes of geography and atmospheric sciences, including their holistic and systems approach, the planetary scales in which they work, and the geotechnologies that they use, it is not surprising that researchers in both fields work closely together. Indeed, some geography departments in universities have merged with atmospheric sciences or else share research projects and faculty (see Geography Departments). Understanding of the atmosphere has been revolutionary to geography, and in turn, geography has been foundational to much work in the atmospheric sciences. Understanding how and why the atmosphere works and changes is fundamental to the understanding of the geography of Planet Earth.

See also: Citizen Science; Defining Geography; Environmental Movement; Field Collection Devices; Geographic Information Systems (GIS); Global Positioning Systems (GPS); Magnetic Field; Remote Sensing; Spatial Analysis

A

AERIAL PHOTOGRAPHY

Examining the Earth from Above

Further Reading

AGRICULTURE

Modifying Planet Earth

Further Reading

AIR TRAVEL

Compressing Distance, Altering Geography

Further Reading

AL-BIRUNI

Laying the Geodetic Foundations

Further Reading

AL-IDRISI, MUHAMMAD

Pleasant Journeys into Faraway Lands

Further Reading

AL-JAHIZ

Connecting Food, the Environment, and Evolution

Further Reading

ANAXIMANDER

The First Map of the World

Further Reading

ANTARCTICA

To the End of the Earth

Further Reading

APPLIED GEOGRAPHY

Solving the World’s Problems

Further Reading

ARYABHATA AND BRAHMAGUPTA

Using Mathematics to Explain Geography

Further Reading

ATMOSPHERIC RESEARCH

Understanding What’s Above

Further Reading