Key Geographic Concepts: Spatial Association, Regions, and Map Scales

spatial association

When the spatial arrangements of two distributions of features correspond or covary with each other in some way.

regional concept

The view that physical and cultural phenomena on the surface of the Earth are rationally arranged by complex, diverse, but comprehensible interrelated spatial processes.

administrative region

Geographic region created by law, treaty, or regulation; includes political regions such as countries and states, and internal regions such as school and voting districts

thematic region

(sometimes formal region) Geographic region based on the pattern of one or more objectively measurable themes or properties, such as soil types or linguistic dialects.

functional region

(sometimes formal region) Geographic region based on the pattern of one or more objectively measurable themes or properties, such as soil types or linguistic dialects.

perceptual region

(syn: cognitive region) Geographic region created informally to reflect the subjective beliefs and feelings of individuals or cultural groups (in the latter case, they are also known as vernacular regions).

representative fraction

The scale of a map expressed as a ratio of a unit of distance on the map to distance measured in the same unit on the ground, e.g., 1:250,000 means that 1 inch on the map represents 250 thousand inches (almost 4 miles) on the Earth surface.

graphic scale

A visual expression of cartographic scale in a map legend, consisting of a graduated line showing how much distance on the map represents a particular distance on the Earth surface.

equator

An imaginary east-west line (parallel of latitude) that encircles the globe halfway between the North and South Poles.

globe

A spherical physical model of the Earth.

graticule

(syn: globe grid) The network of meridians of longitude and parallels of latitude that make up a coordinate reference system on the globe.

parallel

An east-west line of latitude indicating distance north or south of the equator.

latitude

Angular distance of a location north or south of the equator, measured in degrees, minutes, and seconds.

meridian

A north-south line of longitude indicating distance east or west of the prime meridian running through Greenwich, England.

longitude

Angular distance of a location east or west of a designated prime meridian, measured in degrees, minutes, and seconds.

prime meridian

An imaginary line passing through the Royal Observatory at Greenwich, England (now a suburb of London), serving by international agreement as the 0 degree line of longitude.