Chapter 1: Introduction to Human Geography

Human geography emphasizes the importance of geography as a field of inquiry and introduces students to the concept of spatial organization. Knowing the location of places, people, and events is a gateway to understanding complex environmental relationships and interconnections among places and across landscapes.

Geographic concepts emphasize location, space, place, scale of analysis, pattern, regionalization, and globalization. These concepts are essential to understanding spatial interaction and spatial behavior, the dynamics of human population growth and migration, patterns of culture, political control of territory, areas of agricultural production, the changing location of industry and economic development strategies, and evolving human settlement patterns, particularly urbanization. Geographers use geospatial technology (e.g., satellite imagery, aerial photography, geographic information systems (GIS), global positioning systems (GPS), and drone technology), spatial data, mathematical formulas, and design models to understand the world from a spatial perspective better.

Human geography enables us to consider the regional organization of various phenomena and encourages geographic analysis to understand processes in a changing world. For example, geographic perspectives on the impact of human activities on the environment, from local to global scales, include effects on land, water, atmosphere, population, biodiversity, and climate. These human ecological examples are inherent throughout the discipline, especially in topics dealing with population growth, agricultural and industrial practices, and rapid urbanization. Geographers apply geographic methods and geospatial technologies to a variety of situations.

1.1 Geography: The Science of Where, How, and Why

Geography as a Body of Knowledge

Geography seek to answer the “where,” “why,” and the “how.” Simply knowing where a country is located is undoubtedly helpful, but geographers dig deeper:

Why is it located there?
Why does it have a particular shape, and how does this shape affect how it interacts with its neighbors and its access to resources?
Why do the people of the country have certain cultural features?
Why does the country have a specific style of government?
How do we analyze patterns in human-environment interactions?

The list goes on and on, and as you might notice, incorporates a variety of historical, cultural, political, and physical features. This synthesis of the physical world and human activity is at the heart of the regional geographic approach.

The term “geography” comes from the Greek term geo- meaning “the earth” and – graphia meaning “to write,” and many early geographers did exactly that: they wrote about the world. Ibn Battuta, for example, was a scholar from Morocco and traveled extensively across Africa and Asia in the 14th century CE. Eratosthenes is commonly considered to be the “Father of Geography,” and in fact, he quite literally wrote the book on the subject in the third century BCE. His three-volume text, Geographica, included maps of the entire known world, including different climate zones, the locations of hundreds of different cities, and a coordinate system. This was a revolutionary and highly regarded text, especially for the time period. Eratosthenes is also credited as the first person to calculate the circumference of the Earth. Many early geographers, like Eratosthenes, were primarily cartographers, referring to people who scientifically study and create maps, and early maps, such as those used in Babylon, Polynesia, and the Arabian Peninsula, were often used for navigation. In the Middle Ages, as academic inquiry in Europe declined with the fall of the Roman Empire, Muslim geographer Muhammad al-Idrisi created one of the most advanced maps of pre-modern times, inspiring future geographers from the region.

Geography today, though using more advanced tools and techniques, draws on the foundations laid by these predecessors. What unites all geographers, whether they are travelers writing about the world’s cultures or cartographers mapping new frontiers, is an attention to the spatial perspective. As geographer Harm deBlij once explained, there are three main ways to look at the world. One way is chronological, as a historian might examine the sequence of world events. A second way is systematical, as a sociologist might explore the societal systems in place that help shape a given country’s structures of inequality. The third way is spatially, and this is the geographic perspective. Geographers, when confronted with a global problem, immediately ask the questions “Where?” and “Why?” Although geography is a broad discipline that includes quantitative techniques like statistics and qualitative methods like interviews, all geographers share this common way of looking at the world from a spatial perspective.

A Spatial Body of Knowledge

At the heart of the spatial perspective is the question of “where,” but there are a number of different ways to answer this question. Relative location refers to the location of a place relative to other places, and we commonly use relative location when giving directions to people. Wemight instruct them to turn “by the gas station on the corner,” or say that we live “in the dorm across from the fountain.” Another way to describe a place is by referring to its absolute location. Absolute location references an exact point on Earth and commonly uses specific coordinates like latitude and longitude. Lines of latitude and longitude are imaginary lines that circle the globe and form the geographic coordinate system. Lines of latitude run laterally, parallel to the equator, and measure distances north or south of the equator. Lines of longitude, on the other hand, converge at the poles and measure distances east and west of the prime meridian.

Every place on Earth has a precise location that can be measured with latitude and longitude. The location of the White House in Washington, DC, for example, is located at latitude 38.8977 °N and longitude 77.0365°W. Absolute location might also refer to details like elevation. The Dead Sea, located on the boundary of Jordan and Israel, is the lowest location on land, dipping down to 1,378 feet below sea level.

Historically, most maps were hand-drawn, but with the advent of computer technology came more advanced maps created with the aid of satellite technology. Geographic information science (GIS), sometimes also referred to as geographic information systems, uses computers and satellite imagery to capture, store, manipulate, analyze, manage, and present spatial data. GIS essentially uses layers of information and is often used to make decisions in a wide variety of contexts. An urban planner might use GIS to determine the best location for a new fire station, while a biologist might use GIS to map the migratory paths of birds. You might use GIS to get navigation directions from one place to another, layering place names, buildings, and roads.

One difficulty with map-making, even when using advanced technology, is that the earth is roughly a sphere while maps are generally flat. When converting the spherical Earth to a flat map, some distortion always occurs. A map projection, or a representation of Earth’s surface on a flat plane, always distorts at least one of these four properties: area, shape, distance, and direction. Some maps preserve three of these properties, while significantly distorting another, while other maps seek to minimize overall distortion but distort each property somewhat. So, which map projection is best? That depends on the purpose of the map. The Mercator projection, while significantly distorting the size of places near the poles, preserves angles and shapes, making it ideal for navigation.

The Winkel Tripel projection is so-named because its creator, Oswald Winkel, sought to minimize three kinds of distortion: area, direction, and distance. It has been used by the National Geographic Society since 1998 as the standard projection of world maps.

When representing the Earth on a manageable-sized map, the actual size of location is reduced. Scale is the ratio between the distance between two locations on a map and the corresponding distance on Earth’s surface. A 1:1000 scale map, for example, would mean that 1 meters on the map equals 1000 meters, or 1 kilometer, on Earth’s surface. Scale can sometimes be a confusing concept for students, so it’s important to remember that it refers to a ratio. It doesn’t refer to the size of the map itself, but rather, how zoomed in or out the map is. A 1:1 scale map of your room would be the exact same size of your room – plenty of room for significant detail, but hard to fit into your glove compartment.

As with map projections, the “best” scale for a map depends on what it’s used for. If you’re going on a walking tour of a historic town, a 1:5,000 scale map is commonly used. If you’re a geography student looking at a map of the entire world, a 1:50,000,000 scale map would be appropriate. “Large” scale and “small” scale refer to the ratio, not to the size of the landmass on the map. 1 divided by 5,000 is 0.0002, which is a larger number than 1 divided by 50,000,000 (which is 0.00000002). Thus, a 1:5,000 scale map is considered “large” scale while 1:50,000,000 is considered “small” scale.

All maps have a purpose, whether it’s to guide sailing ships, help students create a more accurate mental map of the world, or tell a story. The map projection, color scheme, scale, and labels are all decisions made by the mapmaker. Some argued that the widespread use of the Mercator projection, which made Africa look smaller relative to North America and Eurasia, led people to minimize the importance of Africa’s political and economic issues. Just as texts can be critiqued for their style, message, and purpose, so too can maps be critiqued for the information and message they present.

The spatial perspective, and answering the question of “where,” encompasses more than just static locations on a map. Often, answering the question of “where” relates to movement across space. Diffusion refers to the spreading of something from one place to another, and might relate to the physical movement of people or the spread of disease, or the diffusion of ideas, technology, or other intangible phenomena. Diffusion occurs for different reasons and at different rates. Just as static features of culture and the physical landscape can be mapped, geographers can also map the spread of various characteristics or ideas to study how they interact and change.

1.2 Scientific Inquiry

Science is a path to gaining knowledge about the natural world. The study of science also includes the body of knowledge that has been collected through scientific inquiry. Scientists conduct scientific investigations by asking testable questions that can be systematically observed and careful evidence collected. Then they use logical reasoning and some imagination to develop a testable idea, called a hypothesis, along with explanations to explain the concept — finally, scientists design and conduct experiments based on their hypotheses.

Science seeks to understand the fundamental laws and principles that cause natural patterns and govern natural processes. It is more than just a body of knowledge; science is a way of thinking that provides a means to evaluate and create new knowledge without bias. At its best, science uses objective evidence over subjective evidence to reach sound and logical conclusions.

Truth in science is a difficult concept, and this is because science is falsifiable, which means an initial explanation (hypothesis) is testable and able to be proven false. A scientific theory can never wholly be proven correct; it is only after exhaustive attempts to falsify competing for ideas and variations that the theory is assumed to be true. While it may seem like a weakness, the strength behind this is that all scientific ideas have stood up to scrutiny, which is not necessarily true for non-scientific ideas and procedures. It is the ability to prove current ideas wrong that is a driving force in science and has driven many scientific careers.

Early Scientific Thought

Western science began in ancient Greece, specifically Athens, and early democracies like Athens encouraged individuals to think more independently than in the past when kings ruled most civilizations. Foremost among these early philosophers/scientists was Aristotle, born in 384 B.C.E., who contributed to foundations of knowledge and science. Aristotle was a student of Plato and a tutor to Alexander the Great, who would conquer the Persian Empire as far as India, spreading Greek culture in the process. Aristotle used deductive reasoning, applying what he thought he knew to establish a new idea (if A, then B).

Deductive reasoning starts with generalized principles or established or assumed knowledge and extends them to new ideas or conclusions. If a deductive conclusion is derived from sound principles, then the conclusion has a high degree of certainty. This contrasts with inductive reasoning, which begins from new observations and attempts to discern the underlying principles that explain the observations. Inductive reasoning relies on evidence to infer a conclusion and does not have the perceived certainty of deductive reasoning. Both are important in science. Scientists take existing principles and laws and see if these explain observations. Also, they make new observations and seek to determine the principles and laws that underlie them. Both emphasize the two most important aspects of science: observations and inferences.

The Romans absorbed Greek culture. The Romans controlled people and resources in their Empire by building an infrastructure of roads, bridges, and aqueducts. Their road network helped spread Greek culture and knowledge throughout the Empire. The fall of the Roman Empire ushered in the Medieval period in Europe in which scientific progress in Europe was largely overlooked. During Europe’s Medieval period, science flourished in the Middle East between 800 and 1450 CE as the Islamic civilization developed. Empirical experimentation grew during this time and was a vital component of the scientific revolution that started in 17th century Europe. Empiricism emphasizes the value of evidence gained from testing and observations of the senses. Because of the respect, others hold for Aristotle’s wisdom and knowledge, his logical approach was accepted for centuries and formed an essential basis for understanding nature. The Aristotelian approach came under criticism by 17th-century scholars of the Renaissance.

As science progressed, certain aspects of science that could not be experimented and sensed awaited the development of new technologies, such as atoms, molecules, and the deep-time of geology. The Renaissance, following the Medieval period between the fourteenth and seventeenth centuries, was a great awakening of artistic and scientific thought and expression in Europe.

The foundational example of the modern scientific approach is the understanding of the solar system. The Greek astronomer Claudius Ptolemy, in the second century, using an Aristotelian approach and mathematics, observed the Sun, Moon, and stars moving across the sky and deductively reasoned that Earth must be at the center of the universe with the celestial bodies circling Earth. Ptolemy even had mathematical, astronomical calculations that supported his argument. The view of the cosmos with Earth at its center is called the geocentric model.

In contrast, early Renaissance scholars used new instruments such as the telescope to enhance astronomical observations and developed new mathematics to explain those observations. These scholars proposed a radically new understanding of the cosmos, one in which Earth and the other planets orbited around the centrally located Sun. This is known as the heliocentric model, and astronomer Nicolaus Copernicus (1473-1543) was the first to offer a solid mathematical explanation for it around 1543.

The Scientific Method

Science and scientists are wary of situations that either discourage or avoid the process of falsifiability. If a statement or an explanation of a phenomenon cannot be tested or does not meet scientific standards, then it is not considered science, but instead is considered a pseudoscience. Falsifiability separates science from pseudoscience. Pseudoscience is a collection of ideas that may appear scientific but does not use the scientific method. An example of pseudoscience is astrology, which is a belief system that the movement of celestial bodies influences human behavior. This is not to be confused with astronomy, which is the scientific study of celestial bodies and the cosmos. There are many astronomical observations associated with astrology, but astrology does not use the scientific method. Conclusions in astrology are not based on evidence and experiments, and its statements are not falsifiable.

Science is also a social process. Scientists share their ideas with peers at conferences for guidance and feedback. A scientist’s research paper and data are rigorously reviewed by many qualified peers before publication. Research results are not allowed to be published by a reputable journal or publishing house until other scientists who are experts in the field have determined that the methods are scientifically sound and the conclusions are reasonable. Science aims to “weed out” misinformation, invalid research results, and wild speculation. Thus, the scientific process is slow, cautious, and conservative. Scientists do not jump to conclusions, but wait until an overwhelming amount of evidence from many independent researchers points to the same conclusion before accepting a scientific concept.

Science is the realm of facts and observations, not moral judgments. Scientists might enjoy studying tornadoes, but their opinion that tornadoes are exciting is not essential to learning about them. Scientists increase our technological knowledge, but science does not determine how or if we use that knowledge. Scientists discovered to build an atomic bomb, but scientists did not decide whether or when to use it. Scientists have accumulated data on warming temperatures; their models have shown the likely causes of this warming. However, although scientists are primarily in agreement on the causes of global warming, they cannot force politicians or individuals to pass laws or change behaviors.

For science to work, scientists must make some assumptions. The rules of nature, whether simple or complex, are the same everywhere in the universe. Natural events, structures, and landforms have natural causes, and evidence from the natural world can be used to learn about those causes. The objects and events in nature can be better understood through careful, systematic study. Scientific ideas can change if we gather new data or learn more. An idea, even one that is accepted today, may need to be modified or be entirely replaced if new evidence contradicts previous scientific ideas. However, the body of scientific knowledge can grow and evolve because some theories become more accepted with repeated testing or old theories are modified or replaced with new knowledge.

Scientific research may be done to build knowledge or to solve problems and lead to scientific discoveries and technological advances. Pure research often aids in the development of applied research. Sometimes the results of pure research may be applied long after the pure research was completed. Sometimes something unexpected is discovered while scientists are conducting their research. Some ideas are not testable. For example, supernatural phenomena, such as stories of ghosts, werewolves, or vampires, cannot be tested. Scientists describe what they see, whether in nature or a laboratory.

The scientific method is a series of steps that help to investigate the answer those questions; scientists use data and evidence gathered from observations, experience, or experiments to answer their questions.

However, scientific inquiry rarely proceeds in the same sequence of steps outlined by the scientific method. For example, the order of the steps might change because more questions arise from the data that is collected. Still, to come to valid conclusions, logical, repeatable steps of the scientific method must be followed.

Scientific Research

A scientist will first try to find answers to their questions by researching what may already be known about the topic. This information will allow the scientist to create a good experimental design. If this question has already been answered, the research may be enough, or it may lead to new questions. For example, a farmer researches no-till farming on the Internet, at the library, at the local farming supply store, and elsewhere. She learns about various farming methods, what types of fertilizers are best to use, and what the best crop spacing would be. From her research, she also learns that no-till farming can be a way to reduce carbon dioxide emissions into the atmosphere, which helps in the fight against global warming.

Hypothesis

With the information collected from background research, the scientist creates a plausible explanation for their question, called a hypothesis. The hypothesis must directly answer the question at hand and must be testable. Having a hypothesis guides a scientist in designing experiments and interpreting data. Referring back to the farmer, they would hypothesize that no-till farming will decrease soil erosion on hills of similar steepness as compared to the traditional farming technique because there will be fewer disturbances to the soil.

Data Collection

To support or refute a hypothesis, the scientist must collect data. A great deal of logic and methodology goes into designing tests to collect data so the data can answer scientific questions. Experiment or observation usually gathers data, and sometimes improvements in technology will allow new tests to address a hypothesis better.

Observation is used to collect data when it is not possible for practical or ethical reasons to perform experiments. Written descriptions of observations are qualitative data-based, and this data is used to answer critical questions. Scientists use many various types of instruments to make quantitative measurements, typically based on the scientific discipline. Electron microscopes can be used to explore tiny objects or telescopes to learn about the universe. Probes or drones make observations where it is too dangerous or too impractical for scientists to go.

Objective observation is without personal bias and is observed the same by all individuals. Humans, by their nature, do have a bias, so no observation is entirely free of bias; the goal is to be as free of bias as possible. A subjective observation is based on a person’s feelings and beliefs and is unique to that individual. Science uses quantitative over qualitative objective observations, whenever possible.

A quantitative observation can be measured and expressed with a number. Qualitative observations are not numeric but rather verbal descriptions. For example, saying a rock is red or heavy is qualitative. However, measuring the exact color of red, or measuring the density of the rock (which can be traced to the proportion of certain minerals in the rock) is quantitative. This is why quantitative measurements are much more useful to scientists. Calculations can be done on specific numbers, but cannot be done on qualitative values.

A good experiment must have one factor that can be manipulated or changed, called the independent variable. The rest of the factors must remain the same, called experimental controls. The outcome of the experiment, or what changes as a result of the experiment, is the dependent variable because the variable “depends” on the independent variable.

Return to the example of the farmer. She decides to experiment on two separate hills that have similar steepness and receives similar amounts of sunshine. On one hill, the farmer uses a traditional farming technique that includes plowing. On the other, she uses a no-till method, spacing plants farther apart and using specialized equipment for planting. The plants on both hillsides receive identical amounts of water and fertilizer, and she measures plant growth on both hillsides. In this experiment:

What is the independent variable?
What are the experimental controls?
What is the dependent variable?

The independent variable is the farming technique – either traditional or no-till – because that is what is being manipulated. For a fair comparison of the two farming techniques, the two hills must have the same slope and the same amount of fertilizer and water. These are the experimental controls. The amount of erosion is the dependent variable. It is what the farmer is measuring. During an experiment, scientists make many measurements. Data in the form of numbers is quantitative.

Data gathered from advanced equipment usually goes directly into a computer, or the scientist may put the data into a database. The data can then be statistically analyzed to determine specific relationships between different categories of data. Statistics can make sense of the variability in a data set.

In just about every human endeavor, errors are unavoidable. In a scientific experiment, this is called experimental error. Systematic errors may be inherent in the experimental setup so that the numbers are always skewed in one direction. For example, a scale may always measure one-half ounce high. The error will disappear if the scale is re-calibrated. Random errors may occur because the measurement is not precisely analyzed. For example, a stopwatch may be stopped too soon or too late. Data errors can be corrected by taking several measurements and averaging them. If a result is inconsistent with the results from other samples and many tests have conducted, it is likely that a mistake was made in that experiment, and the inconsistent data point can be thrown out.

Conclusion

Scientists study graphs, tables, diagrams, images, descriptions, and all other available data to conclude from their experiments. Is there an answer to the question based on the results of the experiment? Was the hypothesis supported? Some experiments support a hypothesis entirely, and some do not. If a hypothesis is shown to be wrong, the experiment was not a failure because all experimental results contribute to knowledge. Experiments that do or do not support a hypothesis may lead to even more questions and more experiments.

Let’s return to the farmer again. After a year, the farmer finds that erosion on the traditionally farmed hill is 2.2 times greater than erosion on the no-till hill. She also discovers that the plants on the no-till plots are taller and have higher amounts of moisture in the soil. From this, she decides to convert to no-till farming for future crops. The farmer continues researching to see what other factors may help reduce erosion.

Scientific Theory

As scientists conduct experiments and make observations to test a hypothesis, over time, they collect many data points. If a hypothesis explains all the data and none of the data contradicts the hypothesis, over time, the hypothesis becomes a theory. A scientific theory is supported by many observations and has no significant inconsistencies. A theory must continually be tested and revised by the scientific community. Once a theory has been developed, it can be used to predict behavior. A theory provides a model of reality that is simpler than the phenomenon itself. Even a theory can be overthrown if conflicting data is discovered. However, a longstanding theory that has lots of evidence to back it up is less likely to be removed than a newer theory.

Science does not prove anything beyond a shadow of a doubt. Scientists seek evidence that supports or refutes an idea. If there is no significant evidence to refute an idea and a lot of evidence to support it, the idea is accepted. The more lines of evidence that support an idea, the more likely it will stand the test of time. The value of a theory is when scientists can use it to offer reliable explanations and make accurate predictions.

Scientific Denial

Introductory science courses usually deal with accepted scientific theory, and credible ideas that oppose the standardly accepted theories are not included. This makes it easier for students to understand complex material. A student who further studies a discipline will encounter controversies later. However, at the introductory level, the established science is presented. This section on science denial discusses how some groups of people argue that some established scientific theories are wrong, not based on their scientific merit but rather on the ideology of the group.

When an organization or person denies or doubts the scientific consensus on an issue in a non-scientific way, it is referred to as science denial. The rationale is rarely based on objective scientific evidence but instead is based on subjective social, political, or economic reasons. Science denial is a rhetorical argument that has been applied selectively to issues that some organizations or people oppose. Three (past and current) issues that demonstrate this are: 1) the teaching of evolution in public schools, 2) early links between tobacco smoke and cancer, and 3) anthropogenic (human-caused) climate change. Of these, denial of climate change has a strong connection with geographic science. A climate denier denies explicitly or doubts the scientific conclusions of the community of scientists who specifically study climate.

Science denial generally uses three rhetorical but false arguments. The first argument tries to undermine science by claiming that the methods are flawed or that the science is unsettled. The idea that the science is unsettled creates doubt for a regular citizen. A sense of doubt delays action. Scientists typically avoid claiming universal truths and use language that conveys a sense of uncertainty because scientific ideas change as more evidence is uncovered. This avoidance of universal truths should not be confused with the uncertainty of scientific conclusions.

The second argument attacks the researchers who’re findings they disagree with. They claim that ideology and an economic agenda motivate scientific conclusions. They claim that the researchers want to “get more funding for their research” or “expand government regulation.” This is an ad hominem argument in which a person’s character is attacked instead of the merit of their argument.

The third argument is to demand equal media coverage for a “balanced” view in an attempt to validate the false controversy. This includes equal time in the educational curriculum. For example, the last rhetorical argument would demand that explanations for evolution or climate change be discussed along with alternative religious or anthropogenic ones, even when there is little scientific evidence supporting the alternatives. Conclusions based on the scientific method should not be confused with alternative outcomes based on ideologies. Two entirely different methods for concluding nature are involved and do not belong together in the same course.

The formation of new conclusions based on the scientific method is the only way to change scientific findings. We would not teach Flat Earth geology along with plate tectonics because Flat Earthers do not follow the scientific method. Using the fact that scientists avoid universal truths and change their ideas as more evidence is uncovered is how the scientific process works and shouldn’t be seen as meaning that the science is unsettled. Because of widespread scientific illiteracy, these arguments are used by those who wish to suppress science and misinform the general public.

In a classic case of science denial, the rhetorical arguments were used in the 1950s, ’60s, and ’70s by the tobacco industry and their scientists to deny the links between tobacco and cancer. Once it became clear that the tobacco industry could not show that smoking did not cause cancer, their next strategy was to create a sense of “doubt” on the science. They suggested that science was not yet fully understood, and the issue needed more study. Thus legislative action should be delayed. This false sense of “doubt” is the crucial component that misleads the public and prevents action. This is currently being employed by those who deny human involvement in climate change.

1.3 Geographic Perspective

Physical Perspective

When we describe places, we can discuss their absolute and relative location and their relationship and interaction with other places. As regional geographers, we can dig deeper and explore both the physical and human characteristics that make a particular place unique. Geographers explore a wide variety of spatial phenomena, but the discipline can roughly be divided into two branches: physical geography and human geography. Physical geography focuses on natural features and processes, such as landforms, climate, and water features. Human geography is concerned with human activity, such as culture, language, and religion. However, these branches are not exclusive. You might be a physical geographer who studies hurricanes, but your research includes the human impact from these events. You might be a human geographer who studies food, but your investigations include the ecological impact of agricultural systems. Regional geography takes this holistic approach, exploring both the physical and human characteristics of the world’s regions.

Much of Earth’s physical landscape, from mountains to volcanoes to earthquakes to valleys, has resulted from the movement of tectonic plates. As the theory of plate tectonics describes, these rigid plates are situated on top of a bed of molten, flowing material, much like a cork floating in a pot of boiling water. There are seven major tectonic plates and numerous minor plates.

Where two tectonic plates meet is known as a plate boundary, and boundaries can interact in three different ways. Where two plates slide past one another is called a transform boundary. The San Andreas Fault in California is an example of a transform boundary. A divergent plate boundary is where two plates slide apart from one another. Africa’s Rift Valley was formed by this type of plate movement. Convergent plate boundaries occur when two plates slide towards one another. In this case, where two plates have roughly the same density, upward movement can occur, creating mountains. The Himalaya Mountains, for example, were formed from the Indian plate converging with the Eurasian plate. In other cases, subduction occurs and one plate slides below the other. Here, deep, under-ocean trenches can form. The 2004 Indian Ocean earthquake and tsunami occurred because of a subducting plate boundary off the west coast of Sumatra, Indonesia.

The interaction between tectonic plates and historical patterns of erosion and deposition have generated a variety of landforms across Earth’s surface. Each of the world’s regions has identifiable physical features, such as plains, valleys, mountains, and major water bodies. Topography refers to the study of the shape and features of the surface of the Earth. Areas of high relief have significant changes in elevation on the landscape, such as steep mountains, while areas of low relief are relatively flat.

Another key feature of Earth’s physical landscape is climate. Weather refers to the short-term state of the atmosphere. We might refer to the weather as partly sunny or stormy, for example. Climate, on the other hand, refers to long-term weather patterns and is affected by a place’s latitude, terrain, altitude, and nearby water bodies. Geographers commonly use the Köppen climate classification system to refer to the major climate zones found in the world.

Each climate zone in the Köppen climate classification system is assigned a lettered code, referring to the temperature and precipitation patterns found in the particular region. Climate varies widely across Earth. Cherrapunji, India, located in the CWB climate zone, receives over 11,000 mm (400 in) of rain each year. In contrast, the Atacama Desert (BWk), situated along the western coast of South America across Chile, Peru, Bolivia, and Argentina, typically receives only around 1 to 3 mm (0.04 to 0.12 in) of rain each year.

Earth’s climate has gone through significant changes historically, alternating between long periods of warming and cooling. Since the industrial revolution in the 1800s, however, global climate has experienced a warming phase. 95 percent of scientists agree that this global climate change has resulted primarily from human activities, particularly the emission of greenhouse gasses like carbon dioxide. Fifteen of the last sixteen warmest years ever recorded have occurred since 2000. Overall, this warming has contributed to rising sea levels as the polar ice caps melt, changing precipitation patterns, and the expansion of deserts. The responses to global climate change, and the impacts from it vary by region.

Human Perspective

The physical setting of the world’s places has undoubtedly influenced the human setting; just as human activities have shaped the physical landscape. There are currently around 7.4 billion people in the world, but these billions of people are not uniformly distributed. When we consider where people live in the world, we tend to cluster in areas that are warm and are near water and avoid places that are cold and dry. There are three major population clusters in the world: East Asia, South Asia, and Europe.

Just as geographers can discuss “where” people are located, we can explore “why” population growth is occurring in particular areas. All of the 10 most populous cities in the world are located in countries traditionally categorized as “developing.” These countries typically have high rates of population growth. A population grows, quite simply, when more people are born than die. The birth rate refers to the total number of live births per 1,000 people in a given year. In 2012, the average global birth rate was 19.15 births per 1,000 people.

Subtracting the death rate from the birth rate results in a country’s rate of natural increase (RNI). For example, Madagascar has a birth rate of 37.89 per 1,000 and a death rate of 7.97 per 1,000. 37.89 minus 7.97 is 29.92 per 1,000. If you divide the result by 10, you’d get 2.992 per 100 or 2.992 percent. In essence, this means that Madagascar’s population is increasing at a rate of 2.992 percent per year. The natural increase rate does not include immigration. Some countries in Europe, in fact, have a negative natural increase rate, but their population continues to increase due to immigration.

The birth rate is directly affected by the total fertility rate (TFR), which is the average number of children born to a woman during her childbearing years. In developing countries, the total fertility rate is often 4 or more children, contributing to high population growth. In developed countries, on the other hand, the total fertility rate may be only 1 or 2 children, which can ultimately lead to population decline.

A number of factors influence the total fertility rate, but it is generally connected to a country’s overall level of development. As a country develops and industrializes, it generally becomes more urbanized. Children are no longer needed to assist with family farms, and urban areas might not have large enough homes for big families.

Women increasingly enter the workforce, which can delay childbearing and further restrict the number of children a family desires. Culturally, a shift occurs when industrialized societies no longer value large family sizes. As women’s education increases, women are able to take control of their reproductive rights. Contraceptive use becomes more widespread and socially acceptable.

This shift in population characteristics as a country industrialized can be represented by the demographic transition model (DTM). This model demonstrates the changes in birth rates, death rates, and population growth over time as a country develops. In stage one, during feudal Europe, for example, birth rates and death rates were very high. Populations were vulnerable to drought and disease, and thus population growth was minimal. No country remains in stage one today. In stage two, a decline in death rates leads to a rise in population. This decline in death rates occurred as a result of agricultural productivity and improvements in public health. Vaccines, for example, greatly reduced the mortality from childhood diseases.

Stage two countries are primarily agricultural, and thus there is a cultural and historical preference for large families, so birth rates remain high. Most of Sub- Saharan Africa is in stage two. In stage three, urbanization and increasing access to contraceptives leads to a decline in the birth rate. As country industrializes, women enter the workforce and seek higher education. The population growth begins to slow. Much of Middle and South America, as well as India, are in stage three.

In stage four, birth rates approach the death rates. Women have increased independence as well as educational and work opportunities, and families may choose to have a small number of children or none at all. Most of Europe, as well as China, are in stage four. Some have proposed a stage five of the demographic transition model. In some countries, the birth rate has fallen below the death rate as families choose to have only 1 child. In these cases, a population will decline unless there is significant immigration. Japan, for example, is in stage five and has a total fertility rate of 1.41. Although this is only a model, and each country passes through the stages of demographic transition at different rates, the generalized model of demographic transition holds true for most countries of the world.

As countries industrialize and become more developed, they shift from primarily rural settlements to urban ones. Urbanization refers to the increased proportion of people living in urban areas. As people migrate out of rural, agricultural areas, the proportion of people living in cities increases. As people living in cities have children, this further increases urbanization. For most of human history, we have been predominantly rural. By the middle of 2009, however, the number of people living in urban areas surpassed the number of people living in rural areas for the first time. In 2014, 54 percent of the world’s population lived in urban areas. This is expected to increase to 66 percent by 2050.

The number of megacities, cities with 10 million people or more, has also increased. In 1990, there were 10 megacities in the world. In 2014, there were 28 megacities. Tokyo- Yokohama is the largest metropolitan area in the world with over 38 million inhabitants.

Regional Thinking

The world can be divided into regions based on human and/or physical characteristics. Regions simply refer to spatial areas that share a common feature. There are three types of regions: formal, functional, and perceptual. Formal regions, some- times called homogenous regions, have at least one characteristic in common. A map of religions in Europe, for example, groups countries based on the dominant religion, creating formal regions. This isn’t to say that everyone in Spain is Roman Catholic, but rather that most people in Spain are Roman Catholic. Other for- mal regions might include political affiliation, climate, agricultural zones, or ethnicity. Formal regions might also be established by governmental organizations, such as the case with state or provincial boundaries.

Functional regions, unlike formal regions, are not homogenous in the sense that they do not share a single cultural or physical characteristic. Rather, functional regions are united by a particular function, often economic. Functional regions are some- times called nodal regions and have a nodal arrangement, with a core and surrounding nodes. A metropolitan area, for example, often includes a central city and its surrounding suburbs. We tend to think of the area as a “region” not because everyone is the same religion or ethnicity, or has the same political affiliation, but because it functions as a region. Los Angeles, for example, is the second-most populous city in the United States. However, the region of Los Angeles extends far beyond its official city limits. In fact, over 471,000 workers commute into Los Angeles County from the surrounding region every day. Los Angeles, as with all metropolitan areas, functions economically as a single region and is thus considered a functional region. Other examples of functional regions include church parishes, radio station listening areas, and newspaper subscription areas.

Perceptual regions are not as well-defined as formal or functional regions and are based on people’s perceptions. The southeastern region of the United States is often referred to as “the South,” but where the exact boundary of this region depends on individual perception. Some people might include all of the states that formed the Confederacy during the Civil War. Others might exclude Missouri or Oklahoma. Perceptual regions exist at a variety of scales. In your hometown, there might be a perceptual region called “the west side.” Internationally, regions like the Midlands in Britain or the Swiss Alps are considered perceptual. Similarly, “the Middle East” is a perceptual region. It is perceived to exist as a result of religious and ethnic characteristics, but people wouldn’t necessarily agree on which countries to include. Perceptual regions are real in the sense that our perceptions are real, but their boundaries are not uniformly agreed upon.

As geographers, we can divide the world into a number of different regions based on formal criteria and functional interaction. However, there is a matter of perception, as well. We might divide the world based on landmasses since landmasses often share physical and cultural characteristics. Sometimes water connects people more than land, though. In the case of Europe, for example, the Mediterranean Sea historically provided economic and cultural links to the surrounding countries though we consider them to be three separate continents. Creating regions can often be a question of “lumpers and splitters;” who do you lump together and who do you split apart? Do you have fewer regions united by only a couple characteristics or more regions that share a great deal in common?

Most geographers take a balanced approach to “lumping and splitting,” identifying nine distinct world regions. These regions are largely perceptual, however. Where does “Middle” America end and “South” America begin? Why is Pakistan, a predominantly Muslim country, characterized as “South” Asia and not “Southwest” Asia? Why is Russia its own region? You might divide the world into entirely different regions.

While it might seem like there are clear boundaries between the world’s regions, in actuality, where two regions meet are zones of gradual transition. These transition zones are marked by gradual spatial change. Moscow, Russia, for example, is quite similar to other areas of Eastern Europe, though they are considered two different regions on the map. Likewise, were it not for the Rio Grande and a large boundary fence dividing the cities of El Paso, Texas and Ciudad Juarez, Mexico; you might not realize that this metropolitan area stretches across two countries and world regions. Even within regions, country boundaries often mark spaces of gradual transition rather than a stark delineation between two completely different spaces. The boundary between Peru and Ecuador, for example, is quite relaxed as international boundaries go and residents of the countries can move freely across the boundary to the towns on either side.

Globalization

When we start to explore the spatial distribution of economic development, we find that there are stark differences between and within world regions. Some countries have a very high standard of living and high average incomes, while others have few resources and high levels of poverty. Politically, some countries have stable, open governments, while others have long-standing authoritarian regimes. Thus, world regional geography is, in many ways, a study of global inequality. But the geographic study of inequality is more than just asking where inequalities are present; it is also digging deeper and asking why those inequalities exist. How can we measure inequality? Generally, inequality refers to uneven distributions of wealth, which can actually be challenging to measure. By some accounts, the wealthiest one percent of people in the world have as much wealth as the bottom 99 percent. Wealth inequality is just one facet of global studies of inequality, however. There are also differences in income: around half of the world survives on less than $2 per day, and around one-fifth have less than $1 per day. There are also global differences in literacy, life expectancy, and health care. There are differences in the rights and economic opportunities for women compared to men. There are differences in the way resources are distributed and conserved.

Furthermore, these differences don’t exist in a bubble. The world is increasingly interconnected, a process known as globalization. This increased global integration is economical but also cultural. An economic downturn in one country can affect its trading partners half a world away. A Hollywood movie might be translated into dozens of different languages and distributed worldwide. Today, it is quite easy for a business woman in the United States to video chat with her factory manager in a less developed country. For many, the relative size of the world is shrinking as a result of advances in transportation and communications technology.

For others in the poorest, most debt-ridden countries, the world is not flat. As global poverty rates have decreased over the past few decades, the number of people living in poverty within Sub-Saharan Africa has increased. In addition, while global economic integration has increased, most monetary transactions still occur within rather than between countries. The core countries can take advantage of globalization, choosing from a variety of trading partners and suppliers of raw materials, but the same cannot always be said of those in the periphery.

Globalization has often led to cultural homogenization, as “Western” culture has increasingly become the global culture. American fast food chains can now be found in a majority of the world’s countries. British and American pop music plays on radio stations around the world. The Internet, in particular, has facilitated the rapid diffusion of cultural ideas and values. But how does globalization affect local cultures? Some worry that as global culture has become more homogenized, local differences are slowly erasing. Traditional music, clothing, and food preferences might be replaced by foreign cultural features, which can lead to conflict. There is thus a tension between globalization, the benefits of global connectivity, and local culture.

It is the uniqueness of the world’s regions, the particular combination of physical landscapes and human activities that have captivated geographers from the earliest explorers to today’s researchers. And while it might simply be interesting to read about distant cultures and appreciate their uniqueness, geographers continue to dig deeper and ask why these differences exist. Geography matters. Even as we have become more culturally homogeneous and economically interconnected, there remain global differences in the geography of countries, and these differences can have profound effects. Geographic study helps us understand the relationship between the world’s communities, explain global differences and inequalities, and better address future challenges.

1.4 Map Interpretation

Geographic Coordinate Systems

The geographic coordinate system measures location from only two values, despite the fact that the locations are described for a three-dimensional surface. The two values used to define location are both measured relative to the polar axis of the Earth. The two measures used in the geographic coordinate system are called latitude and longitude.

Latitude is an angular measurement north or south of the equator relative to a point found at the center of the Earth. This central point is also located on the Earth’s rotational or polar axis. The equator is the starting point for the measurement of latitude. The equator has a value of zero degrees. A line of latitude or parallel of 30° North has an angle that is 30° north of the plane represented by the equator. The maximum value that latitude can attain is either 90° North or South. These lines of latitude run parallel to the rotational axis of the Earth.

Lines connecting points of the same latitude, called parallels, have lines running parallel to each other. The only parallel that is also a great circle is the equator. All other parallels are small circles. The following are the most important parallel lines:

Equator, 0 degrees
Tropic of Cancer, 23.5 degrees N
Tropic of Capricorn, 23.5 degrees S
Arctic Circle, 66.5 degrees N
Antarctic Circle, 66.5 degrees S
North Pole, 90 degrees N (infinitely small circle)
South Pole, 90 degrees S (infinitely small circle)

Longitude is the angular measurement east and west of the Prime Meridian. The position of the Prime Meridian was determined by international agreement to be in-line with the location of the former astronomical observatory at Greenwich, England. Because the Earth’s circumference is similar to a circle, it was decided to measure longitude in degrees. The number of degrees found in a circle is 360. The Prime Meridian has a value of zero degrees. A line of longitude or meridian of 45° West has an angle that is 45° west of the plane represented by the Prime Meridian. The maximum value that a meridian of longitude can have is 180° which is the distance halfway around a circle. This meridian is called the International Date Line. Designations of west and east are used to distinguish where a location is found relative to the Prime Meridian. For example, all of the locations in North America have a longitude that is designated west. At 180 degrees of the Prime Meridian in the Pacific Ocean is the International Date Line. The line determines where the new day begins in the world. Now because of this, the International Date Line is not a straight line, rather it follows national borders so that a country is not divided into two separate days.

Ultimately, when parallel and meridian lines are combined, the result is a geographic grid system that allows users to determine their exact location on the planet.

Great and Small Circles

Much of Earth’s grid system is based on the location of the North Pole, South Pole, and the Equator. The poles are an imaginary line running from the axis of Earth’s rotation. The plane of the equator is an imaginary horizontal line that cuts the earth into two halves. This brings up the topic of great and small circles. A great circle is any circle that divides the earth into a circumference of two halves. It is also the largest circle that can be drawn on a sphere. The line connecting any points along a great circle is also the shortest distance between those two points.

Examples of great circles include the Equator, all lines of longitude, the line that divides the earth into day and night called the circle of illumination, and the plane of the ecliptic, which divides the earth into equal halves along the equator. Small circles are circles that cut the earth, but not into equal halves.

Time Zones

Before the late nineteenth century, timekeeping was primarily a local phenomenon. Each town would set their clocks according to the motions of the Sun. Noon was defined as the time when the Sun reached its maximum altitude above the horizon. Cities and towns would assign a clockmaker to calibrate a town clock to these solar motions. This town clock would then represent “official” time, and the citizens would set their watches and clocks accordingly.

The ladder half of the nineteenth century was a time of increased movement of humans. In the United States and Canada, large numbers of people were moving west, and settlements in these areas began expanding rapidly. To support these new settlements, railroads moved people and resources between the various cities and towns. However, because of the nature of how local time was kept, the railroads experience significant problems in constructing timetables for the various stops. Timetables could only become more efficient if the towns and cities adopted some standard method of keeping time.

In 1878, Canadian Sir Sanford Fleming suggested a system of worldwide time zones that would simplify the keeping of time across the Earth. Fleming proposed that the globe should be divided into 24 time zones, every 15 degrees of longitude in width. Since the world rotates once every 24 hours on its axis and there are 360 degrees of longitude, each hour of Earth rotation represents 15 degrees of longitude.

Railroad companies in Canada and the United States began using Fleming’s time zones in 1883. In 1884, an International Prime Meridian Conference was held in Washington D.C. to adopt the standardized method of timekeeping and determined the location of the Prime Meridian. Conference members agreed that the longitude of Greenwich, England would become zero degrees longitude and established the 24 time zones relative to the Prime Meridian. It was also proposed that the measurement of time on the Earth would be made relative to the astronomical measurements at the Royal Observatory at Greenwich. This time standard was called Greenwich Mean Time (GMT).

Today, many nations operate on variations of the time zones suggested by Sir Fleming. In this system, time in the various zones is measured relative the Coordinated Universal Time (UTC) standard at the Prime Meridian. Coordinated Universal Time became the standard legal reference of time all over the world in 1972. UTC is determined from atomic clocks that are coordinated by the International Bureau of Weights and Measures (BIPM) located in France. The numbers located at the bottom of the time zone map indicate how many hours each zone is earlier (negative sign) or later (positive sign) than the Coordinated Universal Time standard. Also, note that national boundaries and political matters influence the shape of the time zone boundaries. For example, China uses a single time zone (eight hours ahead of Coordinated Universal Time) instead of five different time zones.

Coordinate Systems and Map Projections

Depicting the Earth’s three-dimensional surface on a two-dimensional map creates a variety of distortions that involve distance, area, and direction. It is possible to create maps that are somewhat equidistance. However, even these types of maps have some form of distance distortion. Equidistance maps can only control distortion along either lines of latitude or longitude. Distance is often correct on equidistance maps only in the direction of latitude.

On a map that has a large scale, 1:125,000 or larger, distance distortion is usually insignificant. An example of a large-scale map is a standard topographic map. On these maps measuring straight line distance is simple. Distance is first measured on the map using a ruler. This measurement is then converted into a real-world distance using the map’s scale. For example, if we measured a distance of 10 centimeters on a map that had a scale of 1:10,000, we would multiply 10 (distance) by 10,000 (scale). Thus, the actual distance in the real world would be 100,000 centimeters.

Measuring distance along map features that are not straight is a little more difficult. One technique that can be employed for this task is to use several straight-line segments. The accuracy of this method is dependent on the number of straight-line segments used. Another method for measuring curvilinear map distances is to use a mechanical device called an opisometer. This device uses a small rotating wheel that records the distance traveled. The recorded distance is measured by this device either in centimeters or inches.

Distance and Direction on Maps

Like distance, direction is difficult to measure on maps because of the distortion produced by projection systems. However, this distortion is quite small on maps with scales larger than 1:125,000. Direction is usually measured relative to the location of the North or South Pole. Directions determined from these locations are said to be relative to True North or True South. The magnetic poles can also be used to measure direction. However, these points on the Earth are located in spatially different spots from the geographic North and South Pole.

Mapping Our Changing World

Have you ever found driving directions and maps online, used a smartphone to ‘check-in’ to your favorite restaurant, or entered a town name or zip code to retrieve the local weather forecast? Every time you and millions of other users perform these tasks, you are making use of Geographic Information Science (GIScience) and related spatial technologies. Many of these technologies, such as Global Positioning Systems (GPS) and in-vehicle navigation units, are very well-known, and you can probably recall the last time you have used them.

Other applications and services that are the products of GIScience are a little less obvious, but they are every bit as common. If you are connected to the Internet, you are making use of geospatial technologies right now. Every time your browser requests a web page from a Content Delivery Network (CDN), a geographic lookup occurs and the server you are connected to contacts other servers that are closest to it and retrieves the information. This happens so that the delay between your request to view the data and the data being sent to you is as short as possible.

GIScience and the related technologies are everywhere, and we use them every day. When it comes to information, “spatial is special.” Reliance on spatial attributes is what separates geographic information from other types of information. There are several distinguishing properties of geographic information. Understanding them, and their implications for the practice of geographic information science is a key utilizing geographic data.

Geographic data represent spatial locations and non-spatial attributes measured at certain times.
Geographic space is continuous.
Geographic space is nearly spherical.
Geographic data tend to be spatially dependent.

Spatial attributes tell us where things are, or where things were at the time the data were collected. By merely including spatial attributes, geographic data allow us to ask a plethora of geographic questions. Another essential characteristic of geographic space is that it is “continuous.” Although the Earth has valleys, canyons, caves, oceans, and more, there are no places on Earth without a location, and connections exist from one place to another. Outside of science fiction, there are no tears in the fabric of space-time. Modern technology can measure location very precisely, making it possible to generate incredibly detailed depictions of geographic feature location (e.g., of the coastline of the eastern U.S). It is often possible to measure so precisely that we collect more location data than we can store and much more than is useful for practical applications. How much information is useful to store or to display in a map will depend on the map scale (how much of the world we represent within a fixed display such as the size of your computer screen) as well as on the map’s purpose.

In addition to being continuous, geographic data also tend to be spatially dependent. More simply, “everything is related to everything else, but near things are more related than distant things” (which leads to an expectation that things that are near to one another tend to be more alike than things that are far apart). How alike things are in relation to their proximity to other things can be measured by a statistical calculation known as spatial autocorrelation. Without this fundamental property, geographic information science as we know it today would not be possible.

Geographic data comes in many types, from many different sources and captured using many techniques; they are collected, sold, and distributed by a wide array of public and private entities. In general, we can divide the collection of geographic data into two main types: directly collected data and remotely sensed data. Directly collected data are generated at the source of the phenomena being measured. Examples of directly collected data include measurements such as temperature readings at specific weather stations, elevations recorded by visiting the location of interest, or the position of a grizzly bear equipped with a GPS-enabled collar. Also, included here are data derived from surveys (e.g., the census) or observation (e.g., Audubon Christmas bird count).

Remotely sensed data are measured from remote distances without any direct contact with the phenomena or need to visit the locations of interest. Satellite images, sonar readings, and radar are all forms of remotely sensed data.

Maps are both the raw material and the product of geographic information systems (GIS). All maps represent features and characteristics of locations, and that representation depends upon data relevant at a particular time. All maps are also selective; they do not show us everything about the place depicted; they show only the particular features and characteristics that their maker decided to include. Maps are often categorized into reference or thematic maps based upon the producer’s decision about what to include and the expectations about how the map will be used. The prototypical reference map depicts the location of “things” that are usually visible in the world; examples include road maps and topographic maps depicting terrain.

Thematic maps, in contrast, typically depict “themes.” They generally are more abstract, involving more processing and interpretation of data, and often depict concepts that are not directly visible; examples include maps of income, health, climate, or ecological diversity. There is no clear-cut line between reference and thematic maps, but the categories are useful to recognize because they relate directly to how the maps are intended to be used and to decisions that their cartographers have made in the process of shrinking and abstracting aspects of the world to generate the map. Different types of thematic maps include:

Choropleth – a thematic map that uses tones or colors to represent spatial data as average values per unit area

Proportional symbol – uses symbols of different sizes to represent data associated with different areas or locations within the map

Isopleth– also known as contour maps or isopleth maps depict smooth continuous phenomena such as precipitation or elevation

Dot – uses a dot symbol to show the presence of a feature or phenomenon – dot maps rely on a visual scatter to show a spatial pattern

Dasymetric – an alternative to a choropleth map but instead of mapping the data so that the region appears uniform, ancillary information is used to model the internal distribution of the data

1.5 Geospatial Technology

Suppose that you have launched a new business that manufactures solar-powered lawnmowers. You are planning a mail campaign to bring this revolutionary new product to the attention of prospective buyers. However, since it is a small business, you cannot afford to sponsor coast-to-coast television commercials or to send brochures by mail to more than 100 million U.S. households. Instead, you plan to target the most likely customers – those who are environmentally conscious, have higher than average family incomes, and who live in areas where there are enough water and the sunshine to support lawns and solar power.

Fortunately, lots of data are available to help you define your mailing list. Household incomes are routinely reported to banks and other financial institutions when families apply for mortgages, loans, and credit cards. Personal tastes related to issues like the environment are reflected in behaviors such as magazine subscriptions and credit card purchases. Market research companies collect such data and transform it into information by creating “lifestyle segments” – categories of households that have similar incomes and tastes. Your solar lawnmower company can purchase lifestyle segment information by 5-digit ZIP code, or even by ZIP+4 codes, which designate individual households.

Geographic Information Systems

It is astonishing how valuable information from the millions upon millions of transactions that are recorded every day. The fact that lifestyle information products are often delivered by geographic areas, such as ZIP codes, speaks to the appeal of geographic information systems (GIS). The scale of these data and their potential applications are increasing continually with the advent of new mechanisms for sharing information and making purchases that are linked to our GPS-enabled smartphones. A Geographical Information System (GIS) is a computer-based tool used to help people transform geographic data into geographic information.

GIS arose out of the need to perform spatial queries on geographic data (questions addressed to a database such as wanting to know a distance or the location where two objects intersect). A spatial query requires knowledge of locations as well as attributes about that location. For example, an environmental analyst might want to know which public drinking water sources are located within one mile of a known toxic chemical spill. Alternatively, a planner might be called upon to identify property parcels located in areas that are subject to flooding.

Numerous tools exist to help users perform database management operations. Microsoft Excel and Access allow users to retrieve specific records, manipulate the records, and create new user content. ESRI’s ArcGIS allows users to organize and manipulate files, but also map the geographic database files in order to find interesting spatial patterns and processes in graphic form.

Global Positioning Sytems

The use of location-based technologies has reached unprecedented levels. Location- enabled devices, giving us access to a wide variety of LBSs, permeate our households and can be found in almost every mall, office, and vehicle. From digital cameras and mobile phones to in-vehicle navigation units and microchips in our pets, millions of people and countless devices have access to the Global Positioning System (GPS). Most of us have some basic idea of what GPS is, but just what is it, exactly, that we are all connected to?

The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24 hours a day.

In a nutshell, GPS works like this: satellites circle the Earth twice a day in a very and transmit a signal to Earth. GPS receivers (or smartphones and watches) take this information and use trilateration to calculate the user’s exact location. Now, with distance measurements from a few satellites, the receiver can determine the user’s position and display it on the unit’s electronic map.

Using GPS to determine your location is not very useful if you do not know about the landscape around you. For instance, your GPS could tell you that you are in the mall, but without a map, you may not know how to get to the door. There are many stories of people whose maps were out of date, and they followed their GPS into a river or a lake. Remote sensing allows mapmakers to collect physical data from a distance without visiting or interacting directly with the location.

Remote Sensing

The distance between the object and observer can be considerable, for example, imaging from the Hubble telescope, or rather small, as is the case in the use of microscopes for examining bacterial growth. In geography, the term remote sensing takes on a specific connotation dealing with space-borne and aerial imaging systems used to remotely sense electromagnetic radiation reflected and emitted from Earth’s surface.

Remote sensing systems work in much the same way as a desktop scanner connected to a personal computer. A desktop scanner creates a digital image of a document by recording, pixel by pixel, the intensity of light reflected from the document. Color scanners may have three light sources and three sets of sensors, one each for the blue, green, and red wavelengths of visible light. Remotely sensed data, like the images produced by a desktop scanner, consist of reflectance values arrayed in rows and columns that make up raster grids.

Remote sensing is used to solve a host of problems across a wide variety of disciplines. For example, Landsat imagery is used to monitor plant health and foliar changes. In contrast, imagery such as that produced by IKONOS is used for geospatial intelligence applications (yes, that means spying) and monitoring urban infrastructure. Other satellites, such as AVHRR (Advanced High-Resolution Radiometer), are used to monitor the effects of global warming on vegetation patterns on a global scale. The MODIS (Moderate Resolution Imaging Spectroradiometer) Terra and Aqua sensors are designed to monitor atmospheric and oceanic composition in addition to the typical terrestrial applications.