Module 1: Why Geography Matters - Lesson 1.2: Geographic Tools

Introduction to Human Geography

What is Geography?

Geography is recognized as one of the oldest forms of intellectual inquiry, often referred to as the "mother of sciences." Its broad lines of investigation laid the groundwork for the development of numerous separate disciplines, including anthropology, ecology, demography, and economics.

Structure to the discipline is largely credited to Greek geographers. The etymology of the term is derived from two Greek words: GEO, meaning 'Earth', and GRAPHY, meaning 'to write'. Therefore, GEOGRAPHY literally translates to 'earth writing' or 'earth description'.

Core Geographic Inquiries

Geographic investigation revolves around three fundamental components:

  • WHERE: This is the spatial component, which forms the underlying basis for all geographic inquiry. It asks about location and distribution.

  • WHAT: This refers to the content of the investigation, which is variable and depends on the specific nature of the study. It asks about the characteristics of a place or phenomenon.

  • WHY: This is the process component, an attempt to answer the questions posed by the investigation. It seeks to understand the reasons behind patterns and distributions.

Geography's Four Traditions

Geography is traditionally understood through four distinct yet interconnected traditions:

  1. Spatial Tradition (Location Tradition)

    • Focuses on mapping, spatial analysis, and the study of boundaries, densities, movement, and transportation.

    • Utilizes quantitative techniques and tools, notably computerized mapping and Geographic Information Systems (GIS).

    • Key concept: Central Place Theory, which explains the distribution of cities and towns.

    • Studies areal distribution and spatial patterns.

  2. Area Studies Tradition (Regional Tradition)

    • Involves the description of specific regions or areas.

    • Encompasses world regional geography and the analysis of international trends and relationships.

    • Highlights how regions differ from one another.

    • Historically known as the chorographic tradition, emphasizing regional description.

  3. Man-Land Tradition (Human-Environmental, Human-Land, or Culture-Environment Tradition)

    • Examines the intricate impact of humans on nature and, conversely, the impact of nature on humans.

    • Addresses natural hazards, perception of the environment, and environmentalism.

    • Incorporates cultural, political, and population geography.

  4. Earth Science Tradition

    • Primarily concerned with physical geography.

    • Studies the lithosphere (earth's crust), hydrosphere (water), atmosphere (air), and biosphere (life).

    • Investigates Earth-sun interactions.

    • Gave rise to separate disciplines such as geology, mineralogy, paleontology, glaciology, geomorphology, and meteorology.

    • At its core, it is the study of the Earth as the home to humans.

Human Geographers' Focus

Geographers cultivate both spatial and ecological perspectives. Human geographers, specifically, "focus on the interrelationships between people, place and the environment and how these vary spatially and temporally across and between locations." (Knox and Marston 2007, Human Geography: Places and Regions in Global Context. p.35)

Human geography delves into the spatial organization of human activities and the complex relationships people have with their environments. This necessarily involves examining natural physical environments, understanding how they influence and are influenced by human activity.

Having a Geographical Imagination

Cultivating a geographical imagination "allows us to understand changing patterns, processes, and relationships among people, places and regions" (Knox and Marston 2007). It enables a deeper comprehension of global and local dynamics.

Geographic Techniques: Geographic Information Systems (GIS)

What is GIS?

A Geographic Information System (GIS) is a sophisticated system designed to capture, store, manipulate, analyze, manage, and present all types of geographically referenced data. It represents a powerful convergence of cartography, statistical analysis, and database technology.

The Power of GIS

  • The strength of GIS is intrinsically linked to geocoding, which is the process of measuring and recording any object with mathematical precision by assigning coordinates to it.

  • By geocoding, geographers can utilize spatial data to create maps and perform extensive spatial analysis.

  • The foundational concept of spatial analysis within GIS involves stacking layers containing different kinds of data (e.g., parcels, zoning, topography, wetlands, demographics, land cover, imagery, basemap) and comparing them based on their geographical location.

Example 1: Locating a Vineyard in Nelson County, VA

This example demonstrates a practical application of GIS for site selection:

  • Step 1: Consider what measurable factors are important. For a vineyard, factors might include aspect (sun exposure), slope, land use, soil type, and elevation. These factors are assigned a potential point value (e.g., Aspect: 10 points, Slope: 15 points, Land Use: 20 points, Soils: 25 points, Elevation: 30 points, totaling 100 points possible).

  • Step 2: Collect the spatial data/variation of those data. Geographic data for each factor is gathered and represented as distinct layers in the GIS.

  • Step 3: Build a GIS model to define the best locations to build the new vineyard. The model combines these layers, applying the weighted scoring system to produce a composite rating. Locations are then classified by suitability (e.g., <55 points: Unsuitable; 55-65 points: Poor; 65-75 points: Risky; 75-85 points: Good; 85-100 points: Best).

Risk of Misrepresentation in GIS

It is crucial to understand that GIS models can reinforce existing inequalities if not designed ethically. For instance, if "cost" is weighted too highly and "access to public transport" is undervalued in a housing model, it might recommend sites far from jobs and schools, exacerbating social disparities rather than mitigating them.

Ethical Considerations

Geographic techniques, particularly GIS, require careful consideration of ethics:

  • Data scientists must be highly cognizant of the nuances and implications of data curation, management, and analysis.

  • It is vital to understand how data was collected, defined, and represented.

  • An important question to ask is: Under which conditions should geospatial data be restricted? This applies especially to sensitive information like health data or infrastructure data.

Example 2: Fairfax County Rental Program (FCRP)

GIS can be used to manage and understand housing programs. The FCRP oversees nearly 2,500 homes for various demographics (families, singles, seniors, individuals with disabilities). These homes are integrated into communities, offering access to county amenities like recreation, libraries, parks, and public transportation. GIS can help analyze their distribution and accessibility.

Example 3: Save the Elephants (STE) and the Mara Elephant Project (MEP)

This case study highlights the use of spatial data in Elephant Movement Ecology and Conservation.

  • Research Focus: Dr. Jake Wall exemplifies this, studying how abiotic factors (terrain, temperature, rainfall) and biotic factors (human presence, vegetation, nutrients) determine elephant movements across complex landscapes. The ultimate goal is to understand elephants' spatial needs to inform landscape managers.

  • Elephant Movement Patterns: Research has shown that elephants tend to avoid walking up slopes, preferring flat terrain. Climbing 100 meters requires energy equivalent to an extra half-hour of foraging to replace, or expenditure of body reserves. Large, heavyweight herbivores like elephants have high energy replenishment costs, influencing their movement and land use patterns.

  • Conservation Impact: GPS tracking data from collared elephants (e.g., Mountain Bull) can be critical for their salvation. In one instance, tracking data contradicted a claim that Mountain Bull was a habitual crop-raider, saving its life by demonstrating its rare presence in farmer's fields. This data helps in securing safe niches for elephants amidst human encroachment and advocating for coexistence.

  • MEP Aims: The Mara Elephant Project focuses on four key areas: elephant population protection, elephant habitat protection, human-elephant co-existence, and landscape connectivity.

Example 4: Considering the Quality of Public Transit (Blacksburg, VA)

GIS is invaluable for analyzing public transit access:

  • Data Layers: A base map of Blacksburg can be overlaid with various data layers, such as Public Transit Stops (as of May 29, 2021), Public Transit Lines (likewise), and Household within 15 minutes Transit Access data.

  • Analysis: This allows geographers to visualize and quantify areas with good versus poor transit access. Further layers can include Average Aggregate Household Income and Percent Renter Occupied Housing Units.

  • Insights: By combining these layers, it becomes possible to identify how transit access correlates with socio-economic factors, revealing areas where public transit may be serving lower-income households or renters, or where improvements are needed to reduce inequality.

Geographic Techniques: Remote Sensing

What is Remote Sensing?

Remote sensing is fundamentally the science and art of obtaining information about an object or phenomenon without making physical contact with it. Various definitions highlight different aspects:

  • "The art or science of telling something about an object without touching it." (Fischer, Hemphill, and Kover, 1976)

  • "The acquisition of physical data of an object without touch or contact." (Lintz and Simonett, 1976)

  • "The observation of a target by a device separated from it by some distance." (Barrett and Curtis, 1976)

  • "Reconnaissance at a distance." (Colwell, 1966)

  • It involves detecting and recording electromagnetic radiation from target areas, whether directly emitted, reflected solar energy, or reflections of energy transmitted from the sensor itself. (White, 1977)

  • It broadly includes modern sensors, data-processing equipment, information theory, communications theory, space and airborne vehicles, and large-systems theory for aerial or space surveys. (National Academy of Sciences, 1970)

  • The most frequently measured quantity is electromagnetic energy. (Landgrebe, quoted in Swain and Davis, 1978)

Types of Remote Sensing

  1. Passive Remote Sensing

    • Sensors detect reflected or emitted electromagnetic radiation originating from natural sources.

    • Example: A standard photograph captures reflected visible light from the sun.

  2. Active Remote Sensing

    • Sensors provide their own energy source for illumination.

    • The sensor emits radiation (e.g., radar, lidar pulses) which is directed towards the target.

    • The radiation reflected back from the target is then detected and measured by the sensor.

    • Advantage: Active sensors can obtain measurements at any time, regardless of the time of day or season, as they do not rely on external light sources. (Source: nrcan.gc.ca 2015)

The Role of Electromagnetic Energy

Most remote sensing relies on electromagnetic energy, which is radiant energy emitted by all matter with a temperature greater than absolute zero (0^ extrm{o}K).

  • Wavelength and Frequency: The warmer the radiant object, the shorter the frequency of electromagnetic waves it emits. The electromagnetic spectrum includes a wide range: electric currents, heat, radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, gamma rays, and cosmic rays.

  • Common Use: By far, the most common type of remote sensing for geography and natural resources involves the use of Electromagnetic Radiation (EMR), particularly in the visible, infrared, and microwave wavelengths, to study the Earth's surface.

Remote Sensing Example: Amazon Rainforest Deforestation in Rondônia, Brazil

Remote sensing imagery clearly illustrates environmental changes over time:

  • Visible Imagery: Images from different years (e.g., 1975, 1994, 2014, 2020 from U.S. Geological Survey, NASA, Google Earth) show stark evidence of deforestation patterns, often appearing as distinct "fishbone" patterns of cleared land along roads.

  • NIR Composite: Near-infrared (NIR) composites can highlight changes in vegetation with greater clarity, differentiating healthy vegetation from cleared or burnt areas (e.g., images from 1992 vs. 2002).

  • Fire Detection: Satellite imagery also detects fires. Data shows a significant increase in detected fires (hotspots) in the Brazilian Amazon during August to October, coinciding with the season when farmers prepare land for planting soybeans and corn. Global Forest Watch provides specific data on existing forest, deforestation, and active fires.

Example: Fire M3 Hotspots

  • Definition: A hotspot is a satellite image pixel with high infrared intensity, indicating a heat source. After removing known industrial sources, remaining hotspots represent vegetation fires in forests, grasslands, croplands, or logging debris. A single hotspot may represent one fire, or multiple hotspots may delineate a larger fire.

  • Limitations: Not all fires can be identified due to small size or cloud cover obscuring the satellite's view.

  • Data Sources: Fire M3 hotspots are obtained from various satellite imagery sources:

    1. Advanced Very High Resolution Radiometer (AVHRR) imagery (NOAA NESDIS).

    2. Moderate Resolution Imaging Spectroradiometer (MODIS) imagery (NASA LANCE FIRMS, USDA Forest Service).

    3. Visible Infrared Imaging Radiometer Suite (VIIRS) imagery (NASA LANCE FIRMS, University of Maryland, RSAC).

  • Applications: This data is crucial for monitoring active fires, assessing fire danger based on the Fire Weather Index (FWI), mapping fire perimeters, and forecasting fire conditions.

Geographic Techniques: Lidar

What is Lidar?

Lidar (Light Detection and Ranging) is a type of active remote sensing that uses laser pulses to measure distance. It operates by emitting laser light and measuring the time it takes for the reflected light to return to the sensor.

  • Mechanism: When performed from above (e.g., from a plane, helicopter, UAV, or satellite), these measured distances can be converted into heights, generating extremely precise three-dimensional data.

  • Wavelengths: Lidar typically uses electromagnetic energy in the near-infrared wavelengths, just beyond what human eyes can detect.

Lidar Data Characteristics

Lidar systems can collect very high-density data, creating detailed models of terrain and objects. Examples show dense point clouds representing heights above ground, capturing intricate structural details (e.g., of trees).

What are Lidar Data Used For?

Lidar data has an extensive range of applications due to its precision and 3D capabilities:

  • High-Resolution Digital Elevation Models (DEMs): Generating accurate topographical maps.

  • Urban Applications: City planning, infrastructure management, smart city development.

  • Wireless Communications: Optimizing signal propagation and placement of cell towers.

  • Emergency Route Planning: Assessing optimal routes, especially in disaster scenarios.

  • Signal Propagation: Modeling how signals travel through complex environments.

  • Archeology and Building Construction: Site mapping, historical preservation, construction planning, and monitoring.

  • Agriculture/Vegetation: Precision agriculture, forest management, biomass estimation.

  • Shorelines/River Surveys: Mapping coastal erosion, riverbed changes.

  • Coastal Engineering and Flood Management: Designing coastal defenses, flood risk assessment.

  • Erosion Monitoring: Tracking land degradation.

  • Powerlines/Pipelines/Corridor Mapping: Inspecting and managing linear infrastructure.

  • Image Georegistration: Aligning various types of imagery accurately.

  • Autonomous Vehicles: Providing crucial 3D environment data for navigation and obstacle detection.

  • Pollution Mapping: Identifying sources and dispersion of pollutants.

  • Disaster Response: Famously used to measure the rubble at the World Trade Center site, providing critical data on debris quantity and depth, which was otherwise inaccessible and chaotic.

Broad Applications of Remote Sensing

The applications of remote sensing are vast and continually expanding, extending across virtually any discipline that observes the Earth and its atmosphere, and even space. These include:

  • Monitoring urban growth and sprawl.

  • Weather forecasting and climate change studies.

  • Tracking land cover changes over time.

  • Monitoring natural resources (e.g., forests, water bodies).

  • Precision agriculture for optimized crop management.

  • And many, many more, making it an indispensable tool for scientific research and practical management worldwide.