Thinking Geographically

Geography as a Field of Inquiry

• Historical Evolution: Over the last 3,000 years, geography has transformed from a speculative philosophical endeavor into a vigorous area of academic research and applied science.
• Early Motivations: The first geographers studied places and regions for practical purposes, primarily to develop trade routes to distant and dangerous lands. Knowledge of geography was essential for travelers to avoid becoming lost.
• Foundational Scholars: During the early centuries, Chinese, Greek, and North African scholars led geographic research. Their precise measurements and detailed maps established the foundations of cartography, defined as the theory and practice of making visual representations of Earth's surface in the form of maps.
• Eratosthenes (3rd Century B.C.E.):
  • Served as the head librarian at Alexandria.
  • Circumference Calculation: He computed Earth's circumference using the sun's angle at the summer solstice (June 21st) and the distance between Alexandria and Syene in modern-day Egypt. He calculated the circumference to be $46,250\,km$, which was only about $175\,km$ longer than the actual value.
  • Etymology: He is credited with coining the term geography, which literally means "Earth writing."
• Ptolemy (2nd Century A.D.):
  • Published Guide to Geography, which included maps of landmasses as understood at the time and a global grid system.
• Age of Exploration (Beginning approximately 1400 A.D.):
  • Western European scholars moved to the cutting edge of geographic thought as explorers mapped landforms, climates, indigenous cultures, and biota.
  • Key Figures: Representative explorers include Bartholomeu Dias, Christopher Columbus, and Ferdinand Magellan.
  • Later Explorers: Alexander von Humboldt and the Lewis and Clark expedition traveled in the name of geography and natural history.
• Modern Theory Synthesis (18th to Early 20th Centuries): Geographic information collected in European museums and universities allowed scholars to synthesize theories about people and nature, leading to the development of anthropology, geology, and ecology. Examples include Charles Darwin's theory of evolution and Alfred Wegener's theory of continental drift.

Evolutionary Paradigms in Geography

• Carl Sauer and Cultural Landscapes (1925):
  • A geographer from the University of California at Berkeley who argued that cultural landscapes—the human-modified natural landscape specifically containing the imprint of a particular culture—should be the focus of the discipline.
  • Sauer posited that humans have shaped virtually all environments, even those appearing natural (natural landscapes), paving the way for environmental geography (also called cultural ecology or nature-society geography).
• The Quantitative Revolution (1960s):
  • Led by geographers at the University of Washington and elsewhere, this movement stressed empirical measurements, hypothesis testing, mathematical models, and computer programs to explain patterns.
• The Technological Revolution (1970s–Present):
  • The field now relies on high-tech tools to collect and analyze spatial data (any information associated with a location on Earth's surface).

Modern Geographic Technologies

• Remote Sensing:
  • The process of capturing images of Earth's surface from airborne platforms like satellites or airplanes using sensors including photographic, thermal, multispectral, and radar images.
  • Methodology: Uses specific colors of light (bands) from ultraviolet to infrared. Different physical features (soil, rock, water, vegetation, built structures) reflect different wavelengths, allowing for precise mapping.
• Global Positioning System (GPS):
  • An integrated network of satellites orbiting Earth that broadcast location information to handheld receivers. It provides highly accurate latitude and longitude, facilitating precise navigation and distance determination.
• Geographic Information Systems (GIS):
  • Software programs designed to map, analyze, and model spatial data.
  • Thematic Layers: GIS uses individual maps of specific features (roads, streams, elevation) that are overlaid into a comprehensive map to reveal spatial relationships among variables, such as how property values are shaped by surrounding amenities, income, and employment.

The Nature and Subfields of Geography

• Human Geography: The study of spatial variation in patterns and processes related to human activity. Subdisciplines include:
  • Population Geography
  • Cultural Geography
  • Political Geography
  • Economic Geography
  • Agricultural and Rural Geography
  • Urban Geography
• Physical Geography: Concerned with the spatial characteristics of Earth's physical and biological systems (e.g., climate change, biodiversity loss, desertification).
• Environmental Geography: The intersection of human and physical geography.
• Geographical Techniques: Specialized methods like cartography and GIS.
• W. D. Pattison’s Four Traditions (1964):
  1. Earth-science tradition: Equivalent to physical geography.
  2. Culture-environment tradition: Equivalent to environmental geography.
  3. Locational tradition: Cartography and spatial data analysis.
  4. Area-analysis tradition: Regional geography.
• Sustainability: Defined by the Brundtland Commission (1987) as "development that meets the needs of the present without compromising the ability of future generations to meet their own needs."

Geography Basics: Perspective, Scale, and Regions

• Spatial Perspective: An intellectual framework allowing geographers to look at Earth in terms of the relationships among places, asking "why" and "how" patterns occur.
• Scale:
  • Map Scale: The ratio between the distance on a map and the actual distance on Earth.
  • Geographic Scale: A conceptual hierarchy of spaces (neighborhood, urban area, metropolitan area, region, watershed, ecosystem, landscape, biome). It reflects levels of spatial organization.
• Defining Regions: A territory larger than a city containing unifying social or physical characteristics. There are three types:
  1. Formal Regions: Areas with specific uniform characteristics (e.g., Tibet’s uniform culture and Buddhist practices).
  2. Functional (Nodal) Regions: Defined by social and economic relationships and interactions (e.g., the San Francisco Bay Area).
  3. Perceptual Regions: Exist in the minds of people; boundaries are often "fuzzy" (e.g., the American Deep South).
• Sense of Place: People's attachment to and perception of the region they call home.
• Regional Case Study: South Florida: Bounded by the Gulf of Mexico (West), Florida Strait (South), Atlantic Ocean (East), and Interstate 4 (North). Characteristics include a humid subtropical climate, urban centers, Caribbean immigrants, and the Everglades.

Describing Location and Distance

• Coordinate System: A grid of parallels and meridians used to determine absolute location.
  • Longitude (Meridians): Run from the Prime Meridian ($0^\circ$ at Greenwich, England) to the International Date Line ($180^\circ$).
  • Latitude (Parallels): Run from the Equator ($0^\circ$) to the Poles ($90^\circ$).
  • Example: The $49^{th}$ parallel marks the boundary between the western U.S. and Canada.
• Site vs. Situation:
  • Site: The absolute location of a place, including physical and cultural features (e.g., San Francisco on a windswept peninsula at $37^\circ\,N$, $123^\circ\,W$).
  • Situation: Relative location; a place's spatial context and relationship to surrounding areas (e.g., San Francisco as the economic hub of Northern California).
• Absolute vs. Relative Distance:
  • Absolute Distance: Linear space measured in standard units like miles or kilometers.
  • Relative Distance: Measured in terms of connectivity (social, cultural, or economic ties) or the time and money required for travel.
• Time-Space Convergence: The shrinking relative distance between places due to improved technology (e.g., London to New York shrinking from weeks by boat to hours by plane).

Spatial Processes and Interaction

• Complementarity: The degree to which one place can supply what another demands (e.g., Florida supplying winter fruit to the Northeast U.S.).
• Intervening Opportunity: A closer supplier that blocks interaction with a more distant one because transportation costs are lower.
• Transferability: The cost involved in moving goods. Highly influenced by high-value/low-weight ratios (e.g., computer chips have high transferability; heavy fertilizer has low transferability).
• Tobler’s First Law of Geography: "Everything is related to everything else, but near things are more related than distant things."
• Friction of Distance: The hindrance to interaction caused by absolute distance.
• Distance Decay Effect: The decrease in interaction as distance increases.
• The Gravity Model: A formula based on Isaac Newton's law to describe spatial interaction:     $I_{ij} = \frac{P_i \times P_j}{D_{ij}^2}$     where $I_{ij}$ is interaction, $P_i$ and $P_j$ are populations, and $D_{ij}^2$ is the square of the distance. This explains why large cities like New York and Los Angeles remain highly connected despite distance.
• Law of Retail Gravitation (1931): People are drawn to large cities for business. The breaking point is the outer edge of a city's sphere of influence.

Spatial Diffusion

• Definition: The ways phenomena (innovations, trends, diseases) travel over distances.
• Expansion Diffusion:
  • Contagious Diffusion: Spread via direct contact (e.g., the common cold).
  • Hierarchical Diffusion: Transmission between places due to high interaction levels despite distance (e.g., music trends spreading from LA to NY to Chicago/Boston).
• Relocation Diffusion: Spread via the migration of people who carry cultural traditions (e.g., European immigrants bringing traditions to the U.S.).

Map Fundamentals and Projections

• The Geoid: Earth's true three-dimensional shape: a bumpy oblate spheroid, slightly squashed so the diameter is longer at the equator than the poles.
• Projections: Mathematical methods of transferring the geoid to a flat surface. All projections involve distortion in area, direction, distance, or shape.
  • Mercator Projection: Cylindrical; maintains accurate direction (conformal) but severely distorts area at high latitudes (e.g., Greenland appears massive).
  • Fuller Projection: Accurate size and shape of landmasses but destroys cardinal directions.
  • Robinson Projection: A compromise that minimizes errors in area, shape, distance, and direction; used by the National Geographic Society.
  • Peters Projection: An equal-area projection centered on Africa to treat all regions equally.
  • Azimuthal Projection: Planar; centered on the North or South Pole.
• Map Concepts:
  • Aggregation: The size of the unit investigated (e.g., state vs. county).
  • Resolution: The smallest discernable unit on a map.
  • Map Scale: Small-scale maps (e.g., $1:100,000$) cover large areas; large-scale maps (e.g., $1:5,000$) cover small regions with high detail.

Map Types and Symbolization

• Reference Maps: Used for navigation and locating landmarks.
• Thematic Maps: Display one or more variables across an area. Specific types include:
  • Isoline Maps: Use lines of equal value (e.g., points of constant elevation on topographic maps).
  • Proportional Symbols Map: Symbol size indicates magnitude of a value.
  • Location Charts: Charts/graphs associated with mapped locations.
  • Dot Maps: Dots show precise locations of specific occurrences (crimes, births).
  • Choropleth Map: Uses tonal shadings or colors to represent categories of data averages per unit area.
  • Cartograms: Transform space so the political unit with the greatest value is represented by the largest area (e.g., a population cartogram making China and India the largest landmasses).
• Visualizations: Dynamic, interactive, or 3D computer maps.

Cognitive and Preference Mapping

• Cognitive Map: An individual's internal mental image of a place, processed through social, cultural, and psychological frameworks. These reveal perceptions of space; for instance, Eskimos create detailed maps of arctic landmarks, while urban disparities in map detail can reflect economic and language access.
• Preference Map: Displays individual preferences for certain places based on perceived quality of life. In the U.S., California, Florida, and Colorado consistently receive high scores, correlating with high growth rates.

Case Studies in AP Human Geography

• Amish Communities (1987-1988): Human geographers studying medical geography noted that the Amish (who abstain from modern technology and vaccinations) had low "herd immunity," leading to a massive measles epidemic in Pennsylvania and surrounding states.
• Dr. John Snow (1800s): A spatial epidemiologist who mapped cholera cases against water pumps in London to identify the specific well leading to the outbreak.
• Regional Landscape Distinctiveness: Geographers analyze how tourism affects regional identity, sometimes increasing but often decreasing landscape distinctiveness.