Gathering Geographic Data and Census - Vocabulary

Individuals and organizations collect geographic data for various purposes.
Individual data gatherers
- Some individuals gather geographic data for research by observing in the field, creating maps, analyzing photographs and satellite images, and examining data collected by the government.
- Other individuals collect geographic data to assist communities (practical, on-the-ground work).
Organizations
- Organizations often have larger budgets and more resources for gathering information.
- They have access to more sophisticated data collection techniques.
Census
- Census is an official count or survey of a population, typically recording details such as age, sex, and race.
- Governments and private companies use data collected by the Census Bureau for a wide variety of purposes: representation, economic trends, funding, and the administration of public programs.
Summary connection to broader concepts
- Geographic data collection spans from local, field-based work to large-scale, resource-intensive organizational efforts.
- Census data underpin decisions that affect representation and resource allocation in public programs.

Data collection methods
- Photo-based analysis: Notable urban changes are visible when comparing archival photos to current images (e.g., Times Square in 1908 vs. 2019).
- Fieldwork: Involves first-hand experience outside the classroom; inherently local because a person can be in only one place at a time.
- To view larger patterns, geographers use sophisticated geospatial technologies that rely on a whole-Earth mapping system.
Latitude and longitude (absolute location)
- Absolute location: A precise position on Earth's surface.
- Latitude lines
- Horizontal lines circling Earth parallel to the equator.
- Latitude measures distance north or south from the equator (0°) to the poles (±{90}^{\circ}).
- Longitude lines
- Vertical lines on Earth's surface that connect the North Pole with the South Pole.
- Longitude lines converge at the poles, so they are not parallel and their distance is not constant.
Prime meridian
- The zero-degree longitude line that runs through Greenwich, England; also known as the Greenwich Meridian.
- Lines of latitude and longitude are measured from the center of the Earth.
- By international agreement, the prime meridian at 0° runs through Greenwich, England, U.K. (example shown with a photo at the Royal Greenwich Observatory).
Significance of these concepts
- Latitude and longitude provide a universal grid for locating places on the planet.
- The prime meridian anchors the longitude system, enabling global navigation and mapping.

Global Positioning System (GPS)
- A system of 24 satellites that orbit Earth daily and transmit radio signals to receivers on the ground.
- The basis for many map-based apps that provide directions (how to get from one place to another).
Geographic Information System (GIS)
- A software application for capturing, storing, checking, and displaying data related to positions on Earth's surface.
- Allows rapid manipulation of geospatial data for problem-solving and research.
Remote sensing
- The scanning of Earth by satellite or high-flying aircraft to obtain information about it.
Aerial photography
- Remote-sensing photography that produces fine-grained, high-resolution, highly detailed images.
Satellite imagery
- Images of Earth's surface gathered from sensors mounted on orbiting satellites.
- Sensors record data in both visible and non-visible portions of the electromagnetic spectrum, enabling analysis of patterns and processes that may be invisible to the naked eye.

Effects of census data
- Census data have important implications for the people who live in a place and how they go about their daily lives (e.g., representation, funding, policy decisions).
Effects of satellite data
- Satellite data enable better understanding of how Earth is changing, which helps experts make better decisions.
Example and interpretation
- Population density in Egypt is heaviest along the banks of the Nile; access to water is a concern for people in this desert region.
Review prompt examples
- Which country is experiencing the most severe drought within its borders?
- How might an analysis of a drought map affect government decisions related to environmental issues?
Practical and ethical considerations
- Using census data responsibly affects representation and resource distribution.
- Satellite data improve understanding of environmental changes but raise considerations about surveillance and privacy in some contexts.

Key takeaway: Geographic data come from diverse sources (individuals, organizations, census) and are gathered through multiple methods (fieldwork, photo analysis, remote sensing, GIS, GPS).
The tools of geospatial technology (GPS, GIS, remote sensing, aerial photography, satellite imagery) enable both fine-grained local insight and broad, planet-scale analysis.
The decisions informed by geographic data have tangible outcomes in representation, funding, public services, environmental policy, and understanding of global change.
Connecting concepts: Absolute location (latitude and longitude) provides a universal reference that underpins all geospatial technologies and analyses.

Census: ext{official count or survey of a population} ; used for representation, funding, public programs.
Absolute location: precise position on Earth's surface.
Latitude: horizontal lines; measures distance from the equator; 0^{\circ} to 90^{\circ}.
Longitude: vertical lines; converges at the poles; distance between lines varies.
Prime meridian: 0^{\circ} longitude, Greenwich, England.
GPS: 24 satellites orbiting Earth, transmitting signals.
GIS: software for capturing, storing, and displaying geospatial data.
Remote sensing: satellite or aircraft-based data collection.
Aerial photography: high-resolution remote sensing imagery.
Satellite imagery: data from sensors on orbiting satellites across visible and non-visible spectra.