Data HelpDesk - GIS Glossary
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1) Relationship between the dimensions of a feature on a map and the geographic features they represent on the earth, commonly expressed as a fraction. For example map scale of 1:24000 means that one unit of measure on the map equals 24000 of the same unit on the earth (1 inch would equal 24000 inches =2000 feet).
2) A calibrated line, as on a map or an architectural plan, indicating such a proportion.
3) Description of how length in the real world is related to length on a map. This can be portrayed in a variety of ways including a representational fraction.
Acronym for Spatial Data Transfer Standard for transferring data between multiple geographic data management systems. Includes metadata that addresses internal spatial reference, completeness, positional and attribute accuracy, logical consistency, completeness and data dictionary.
One of the three kinds of Data (spatial, textural and image). Spatial data is categorized according to the following feature types:
Zero dimensional features: Primitive Points; topological Node.
One dimensional features: Primitive Lines, Strings (multiple nonbranching lines), arcs mathematically defined curve; topological Links, chains, and rings.
Two-dimensional features: Polygons defining enclosed areas, Pixels, and Grid Cells.
Satellite Pour L'Observation de la Terre - the SPOT series of earth observation satellites are operated by CNES, France. SPOT 1 was launched 22 February 1986, SPOT 2 was launched 21 January 1990 and is currently operational and SPOT 3 was launched 26 September 1993 and is currently fully operational. SPOT satellites are operated in a sun synchronous near polar orbit. Satellite altitude is 830km and the repeat cycle is 26 days. SPOT 4 is proposed for launch in December 1997.
Acronym for Structured Query Language, a computer industry-standard syntax language for querying and manipulating most relational database management systems (DBMS). Commands can be embedded within a programming language to interface to a database or used interactively.
State Plane Coordinate System
System of X,Y coordinates defined by the USGS for each state. Locations are based on the distance from an origin point defined for each state.