GLOSSARY

Ad hoc query: A query fashioned from all available data integrated into the GIS.

Cartography: The art or science of making maps.

Census tract: A boundary created by the U.S. Census Bureau that divides counties into populations ranging from 2,500 to 8,000.

Customized query: A predefined query based on user needs, used with systems in which the user does not have access to all data.

Database: A collection of data organized especially for rapid search and retrieval.

Dataset: When a database is linked to the graphics software, integrated disparate datasets are referred to as layers of information because they are displayed in map form.

Polygon: Any shape that is totally enclosed (e.g., circle, square) or any irregular shape that can be defined, such as census tracts, state or county boundaries, and school districts.

Spatial data: Data that are identified with a geographical location, such as x–y coordinates in latitude and longitude, state plane coordinates, street addresses, census tracts, counties, and ZIP Codes.

Spatial or geographic identifier: A location that can be defined geographically (e.g., street addresses, block groups, neighborhoods, police districts, state or county boundaries).

Street centerline: Lines on a map that represent roads; the yellow dashes that separate a two-way street.