- Understand the focus of geography and the two main branches of the discipline.
- Learn about the tools geographers use to study the earth’s surface.
- Summarize the grid system of latitude and longitude and how it relates to seasons and time zones.
- Distinguish between the different types of regional distinctions recognized in geography.
- Understand the spatial nature of geography and how each place or region is examined, analyzed, and compared with other places or regions.
- Determine the basic geographic realms and their locations.
What Is Geography?
Geography is the spatial study of the earth’s surface (from the Greek geo, which means “Earth,” and graphein, which means “to write”). Geographers study the earth’s physical characteristics, its inhabitants and cultures, phenomena such as climate, and the earth’s place within the universe. Geography examines the spatial relationships between all physical and cultural phenomena in the world. Geographers also look at how the earth, its climate, and its landscapes are changing due to cultural intervention.
The first known use of the word geography was by Eratosthenes of Cyrene (modern-day Libya in North Africa), an early Greek scholar who lived between 276 and 194 BCE. He devised one of the first systems of longitude and latitude and calculated the earth’s circumference. Additionally, he created one of the first maps of the world based on the available knowledge of the time. Around the same time, many ancient cultures in China, southern Asia, Polynesia, and the Arabian Peninsula also developed maps and navigation systems used in geography and cartography.
The discipline of geography can be broken down into two main areas of focus: physical geography and human geography. These two main areas are similar in that they both use a spatial perspective, and they both include the study of place and the comparison of one place with another.
Physical geography is the spatial study of natural phenomena that make up the environment, such as rivers, mountains, landforms, weather, climate, soils, plants, and any other physical aspects of the earth’s surface. Physical geography focuses on geography as a form of earth science. It tends to emphasize the main physical parts of the earth—the lithosphere (surface layer), the atmosphere (air), the hydrosphere (water), and the biosphere (living organisms)—and the relationships between these parts.
The major forms of study within physical geography include the following:
- Geomorphology (the study of the earth’s surface features)
- Glaciology (the study of glaciers)
- Coastal geography (the study of the coastal regions)
- Climatology (the study of climates and climate change)
- Biogeography (the study of the geographic patterns of species distribution)
Some physical geographers study the earth’s place in the solar system. Others are environmental geographers, part of an emerging field that studies the spatial aspects and cultural perceptions of the natural environment. Environmental geography requires an understanding of both physical and human geography, as well as an understanding of how humans conceptualize their environment and the physical landscape.
Physical landscape is the term used to describe the natural terrain at any one place on the planet. The natural forces of erosion, weather, tectonic plate action, and water have formed the earth’s physical features. Many US state and national parks attempt to preserve unique physical landscapes for the public to enjoy, such as Yellowstone, Yosemite, and the Grand Canyon.
Human geography is the study of human activity and its relationship to the earth’s surface. Human geographers examine the spatial distribution of human populations, religions, languages, ethnicities, political systems, economics, urban dynamics, and other components of human activity. They study patterns of interaction between human cultures and various environments and focus on the causes and consequences of human settlement and distribution over the landscape. While the economic and cultural aspects of humanity are primary focuses of human geography, these aspects cannot be understood without describing the landscape on which economic and cultural activities take place.
The cultural landscape is the term used to describe those parts of the earth’s surface that have been altered or created by humans. For example, the urban cultural landscape of a city may include buildings, streets, signs, parking lots, or vehicles, while the rural cultural landscape may include fields, orchards, fences, barns, or farmsteads. Cultural forces unique to a given place—such as religion, language, ethnicity, customs, or heritage—influence the cultural landscape of that place at a given time. The colors, sizes, and shapes of the cultural landscape usually symbolize some level of significance regarding societal norms. Spatial dynamics assist in identifying and evaluating cultural differences between places.
Traditionally, the field of cartography, or map making, has been a vital discipline for geographers. While cartography continues to be an extremely important part of geography, geographers also look at spatial (space) and temporal (time) relationships between many types of data, including physical landscape types, economies, and human activity. Geography also examines the relationships between and the processes of humans and their physical and cultural environments. Because maps are powerful graphic tools that allow us to illustrate relationships and processes at work in the world, cartography and geographic information systems have become important in modern sciences. Maps are the most common method of illustrating different spatial qualities, and geographers create and use maps to communicate spatial data about the earth’s surface.
Geospatial techniques are tools used by geographers to illustrate, manage, and manipulate spatial data. Cartography is the art and science of making maps, which illustrate data in a spatial form and are invaluable in understanding what is going on at a given place at a given time.
Making maps and verifying a location have become more exact with the development of the global positioning system (GPS). A GPS unit can receive signals from orbiting satellites and calculate an exact location in latitude and longitude, which is helpful for determining where one is located on the earth or for verifying a point on a map. GPS units are standard equipment for many transportation systems and have found their way into products such as cell phones, handheld computers, fish finders, and other mobile equipment. GPS technology is widely implemented in the transport of people, goods, and services around the world.
Remote sensing technology acquires data about the earth’s surface through aerial photographs taken from airplanes or images created from satellites orbiting the earth. Remotely sensed images allow geographers to identify, understand, or explain a particular landscape or determine the land use of a place. These images can serve as important components in the cartographic (map-making) process. These technologies provide the means to examine and analyze changes on the earth’s surface caused by natural or human forces. Google Earth is an excellent example of a computer tool that illustrates remotely sensed images of locations on the earth.
Geographic information science (GIS), often referred to as geographic information systems, uses a computer program to assimilate and manage many layers of map data, which then provide specific information about a given place. GIS data are usually in digital form and arranged in layers. The GIS computer program can sort or analyze layers of data to illustrate a specific feature or activity. GIS programs are used in a wide range of applications, from determining the habitat range of a particular species of bird to mapping the hometowns of university students.
GIS specialists often create and analyze geographical information for government agencies or private businesses. They use computer programs to take raw data to develop the information these organizations need for making vital decisions. For example, in business applications, GIS can be used to determine a favorable location for a retail store based on the analysis of spatial data layers such as population distribution, highway or street arrangements, and the locations of similar stores or competitive establishments. GIS can integrate a number of maps into one to help analysts understand a place in relation to their own specific needs.
GIS also focuses on storing information about the earth (both cultural and natural) in computer databases that can be retrieved and displayed in the form of specialized maps for specific purposes or analyses. GIS specialists require knowledge about computer and database systems. Over the last two decades, GIS has revolutionized the field of cartography: nearly all cartography is now done with the assistance of GIS software. Additionally, analysis of various cultural and natural phenomena through the use of GIS software and specialized maps is an important part of urban planning and other social and physical sciences. GIS can also refer to techniques used to represent, analyze, and predict spatial relationships between different phenomena.
Geography is a much broader field than many people realize. Most people think of area studies as the whole of geography. In reality, geography is the study of the earth, including how human activity has changed it. Geography involves studies that are much broader than simply understanding the shape of the earth’s landforms. Physical geography involves all the planet’s physical systems. Human geography incorporates studies of human culture, spatial relationships, interactions between humans and the environment, and many other areas of research that involve the different subspecialties of geography. Students interested in a career in geography would be well served to learn geospatial techniques and gain skills and experience in GIS and remote sensing, as they are the areas within geography where employment opportunities have grown the most over the past few decades.
The Earth and Graticule Location
When identifying a region or location on the earth, the first step is to understand its relative and absolute locations. Relative location is the location on the earth’s surface with reference to other places, taking into consideration features such as transportation access or terrain. Relative location helps one compare the advantages of one location with those of another. Absolute location, on the other hand, refers to an exact point on the earth’s surface without regard to how that point is related to any other place. Absolute location is vital to the cartographic process and to human activities that require an agreed-upon method of identifying a place or point.
Just as you were taught in geometry that there are 360 degrees in a circle or a sphere, the earth also has 360 degrees, and they are measured using a grid pattern called the graticule. Lines of latitude and longitude allow any absolute location on the earth to have an identifiable address of degrees north or south and east or west, which allows geographers to accurately locate, measure, and study spatial activity.
Geographers and cartographers organize locations on the earth using a series of imaginary lines that encircle the globe. The two primary lines are the equator and the prime meridian. From these lines, the systems of longitude and latitude are formed, allowing you to locate yourself anywhere on the planet. The line is the longest when you travel along in an east-west direction. At the equator, the sun is directly overhead at noon on the two equinoxes, which occur in March and September.
Figure 1.3 Basic Lines of Longitude and Latitude
Parallels or Lines of Latitude
The equator is the largest circle of latitude on Earth. The equator divides the earth into the Northern and Southern Hemispheres and is called 0 degrees latitude. The other lines of latitude are numbered from 0 to 90 degrees going toward each of the poles. The lines north of the equator toward the North Pole are north latitude, and each of the numbers is followed by the letter “N.” The lines south of the equator toward the South Pole are south latitude, and each of the numbers is followed by the letter “S.” The equator (0 latitude) is the only line of latitude without any letter following the number. Notice that all lines of latitude are parallel to the equator (they are often called parallels) and that the North Pole equals 90 degrees N and the South Pole equals 90 degrees S. Noted parallels include both the Tropic of Cancer and the Tropic of Capricorn, which are 23.5 degrees from the equator. At 66.5 degrees from the equator are the Arctic Circle and the Antarctic Circle near the North and South Pole, respectively.
Meridians or Lines of Longitude
The prime meridian sits at 0 degrees longitude and divides the earth into the Eastern and Western Hemispheres. The prime meridian is defined as an imaginary line that runs through the Royal Observatory in Greenwich, England, a suburb of London. The Eastern Hemisphere includes the continents of Europe, Asia, and Australia, while the Western Hemisphere includes North and South America. All meridians (lines of longitude) east of the prime meridian (0 and 180) are numbered from 1 to 180 degrees east (E); the lines west of the prime meridian (0 and 180) are numbered from 1 to 180 degrees west (W). The 0 and 180 lines do not have a letter attached to them. The meridian at 180 degrees is called the International Date Line. The International Date Line (180 degrees longitude) is opposite the prime meridian and indicates the start of each day (Monday, Tuesday, etc.). Each day officially starts at 12:01 a.m., at the International Date Line. Do not confuse the International Date Line with the prime meridian (0 longitude). The actual International Date Line does not follow the 180-degree meridian exactly. A number of alterations have been made to the International Date Line to accommodate political agreements to include an island or country on one side of the line or another.
Climate and Latitude
The earth is tilted on its axis 23.5 degrees. As it rotates around the sun, the tilt of the earth’s axis provides different climatic seasons because of the variations in the angle of direct sunlight on the planet. Places receiving more direct sunlight experience a warmer climate. Elsewhere, the increased angle of incoming solar radiation near the earth’s poles results in more reflected sunlight and thus a cooler climate. The Northern Hemisphere experiences winter when sunlight is reflected off the earth’s surface and less of the sun’s energy is absorbed because of a sharper angle from the sun.
The Tropic of Cancer is the parallel at 23.5 degrees north of the equator, which is the most northerly place on Earth, receiving direct sunlight during the Northern Hemisphere’s summer. Remember that the earth is tilted 23.5 degrees, which accounts for seasonal variations in climate. The Tropic of Capricorn is the parallel at 23.5 degrees south of the equator and is the most southerly location on Earth, receiving direct sunlight during the Southern Hemisphere’s summer.
The tropics (Cancer and Capricorn) are the two imaginary lines directly above which the sun shines on the two solstices, which occur on or near June 20 or 21 (summer solstice in the Northern Hemisphere) and December 21 or 22 (winter solstice in the Northern Hemisphere). The sun is directly above the Tropic of Cancer at noon on June 20 or 21, marking the beginning of summer in the Northern Hemisphere and the beginning of winter in the Southern Hemisphere. The sun is directly above the Tropic of Capricorn at noon on December 21 or 22, marking the beginning of winter in the Northern Hemisphere and the beginning of summer in the Southern Hemisphere. Solstices are the extreme ends of the seasons, when the line of direct sunlight is either the farthest north or the farthest south that it ever goes. The region between the Tropics of Cancer and Capricorn is known as the tropics. This area does not experience dramatic seasonal changes because the amount of direct sunlight received does not vary widely. The higher latitudes (north of the Tropic of Cancer and south of the Tropic of Capricorn) experience significant seasonal variation in climate.
The Arctic Circle is a line of latitude at 66.5 degrees north. It is the farthest point north that receives sunlight during its winter season (90 N − 23.5 = 66.5 N). During winter, the North Pole is away from the sun and does not receive much sunlight. At times, it is dark for most of the twenty-four-hour day. During the Northern Hemisphere’s summer, the North Pole faces more toward the sun and may receive sunlight for longer portions of the twenty-four-hour day. The Antarctic Circle is the corresponding line of latitude at 66.5 degrees south. It is the farthest location south that receives sunlight during the winter season in the Southern Hemisphere (90 S − 23.5 = 66.5 S). When it is winter in the north, it is summer in the south.
The Arctic and Antarctic Circles mark the extremities (southern and northern, respectively) of the polar day (twenty-four-hour sunlit day) and the polar night (twenty-four-hour sunless night). North of the Arctic Circle, the sun is above the horizon for twenty-four continuous hours at least once per year and below the horizon for twenty-four continuous hours at least once per year. This is true also near the Antarctic Circle, but it occurs south of the Antarctic Circle, toward the South Pole. Equinoxes, when the line of direct sunlight hits the equator and days and nights are of equal length, occur in the spring and fall on or around March 20 or 21 and September 22 or 23.
Universal Time (UT), Coordinated Universal Time (UTC), Greenwich Mean Time (GMT), or Zulu Time (Z): all four terms can be defined as local time at 0 degrees longitude, which is the prime meridian (location of Greenwich, England). This is the same time under which many military operations, international radio broadcasts, and air traffic control systems operate worldwide. UTC is set in zero- to twenty-four-hour time periods, as opposed to two twelve-hour time periods (a.m. and p.m.). The designations of a.m. and p.m. are relative to the central meridian: a.m. refers to ante meridiem, or “before noon,” and p.m. refers to post meridiem, or “after noon.” UT, UTC, GMT, and Z all refer to the same twenty-four-hour time system that assists in unifying a common time in regard to global operations. For example, all air flights use the twenty-four-hour time system so the pilots can coordinate flights across time zones and around the world.
The earth rotates on its axis once every twenty-four hours at the rate of 15 degrees per hour (15 × 24 = 360). Time zones are established roughly every 15 degrees longitude so that local times correspond to similar hours of day and night. With this system, the sun is generally overhead at noon in every time zone that follows the 15-degree-wide system. The continental United States has four main time zones (see Table 1.1 “Four Main Time Zones in the Continental United States and Their Central Meridians” and Figure 1.7 “Major Time Zones of the World”).
Figure 1.7 Major Time Zones of the World
The twenty-four times zones are based on the prime meridian in regard to Universal Coordinated Time (UTC), Greenwich Mean Time (GMT), or Zulu Time (Z), which all operate on the twenty-four-hour time clock. Local time zones are either plus or minus determined by the distance from the prime meridian.
The eastern standard time zone is five hours earlier than the time at the prime meridian (UTC) because it is about 75 degrees west of 0 degrees (5 × 15 = 75). For example, if it is noon in London, then it is 7 a.m. in New York. If it is 1 p.m. in New York, it is 10 a.m. in San Francisco, which is three times zones to the west. Since there are twenty-four hours in a day, there are twenty-four time zones on Earth. Each time zone is 15 degrees wide.
A problem with the 15-degree time zones is that the zones do not necessarily follow state, regional, or local boundaries. The result is that time zones are seldom exactly 15 degrees wide and usually have varied boundary lines. In the United States, the boundaries between the different time zones are inconsistent with the lines of longitude; in some cases, time zones zigzag to follow state lines or to keep cities within a single time zone. Other countries address the problem differently. China, for example, is as large in land area as the United States yet operates on only one time zone for the entire country.