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Map algebra is an algebra for manipulating geographic data, primarily fields.Developed by Dr. Dana Tomlin and others in the late 1970s, it is a set of primitive operations in a geographic information system (GIS) which allows one or more raster layers ("maps") of similar dimensions to produce a new raster layer (map) using mathematical or other operations such as addition, subtraction etc.
Height fields (also known as "2 1/2 dimensional surfaces") model three-dimensional phenomena by a single functional surface, in which elevation is a function of two-dimensional location, allowing it to be represented using field techniques such as isolated points, contour lines, raster (the digital elevation model), and triangulated irregular ...
The algorithm to derive this corridor field is created by generating two cost accumulation grids: one using the source as described above. Then the algorithm is repeated, but using the destination as the source. Then these two grids are added using map algebra. This works because for each cell, the optimal source-destination path passing ...
Various basic measurements can be derived from the terrain surface, generally applying the techniques of vector calculus.That said, the algorithms typically used in GIS and other software use approximate calculations that produce similar results in much less time with discrete datasets than the pure continuous function methods. [8]
Examples of topological spatial relations. Fundamental to the spatial join operation is the formulation of a spatial relationship between two geometric primitives as a logical predicate; that is, a criterion that can be evaluated as true or false. [3]
Triangulated irregular network TIN overlaid with contour lines. In computer graphics, a triangulated irregular network (TIN) [1] is a representation of a continuous surface consisting entirely of triangular facets (a triangle mesh), used mainly as Discrete Global Grid in primary elevation modeling.
Viewshed analysis is a computational algorithm that delineates a viewshed, the area that is visible (on the base terrain surface) from a given location. It is a common part of the terrain analysis toolset found in most geographic information system (GIS) software.
ArcMap is the former main component of Esri's ArcGIS suite of geospatial processing programs. Used primarily to view, edit, create, and analyze geospatial data. ArcMap allows the user to explore data within a data set, symbolize features accordingly, and create maps.