- Map algebra
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Map algebra is a simple and an elegant set based algebra for manipulating geographic data, proposed by Dr. Dana Tomlin in the early 1980s. It is a set of primitive operations in a Geographic Information System (GIS) which allows two or more raster layers ("maps") of similar dimensions to produce a new raster layer (map) using algebraic operations such as addition, subtraction etc.
Depending on the spatial neighborhood, GIS transformations are categorized into four classes: local, focal, global, and zonal. Local operations works on individual raster cells, or pixels. Focal operations work on cells and their neighbors, whereas global operations work on the entire layer. Finally, zonal operations work on areas of cells that share the same value. The input and output for each operator being map, the operators can be combined into a procedure, script, to perform complex tasks.[1]
References
- ^ Longley et al.. Geographic Information Systems and Science. John Wiley & Sons, Inc.. pp. 414–7. ISBN 978-0-470-72144-5.
- B.E. Davis GIS: A Visual Approach (2001 Cengage Learning) pp. 249ff.
Categories:- Geographic information systems
- Cartography stubs
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