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Fields as a framework for integrating GIS and environmental process models. Part 2: Specifying field variables
Author(s) -
KEMP KAREN K
Publication year - 1996
Publication title -
transactions in gis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 63
eISSN - 1467-9671
pISSN - 1361-1682
DOI - 10.1111/j.1467-9671.1996.tb00047.x
Subject(s) - variable (mathematics) , field (mathematics) , polygon (computer graphics) , computer science , spatial analysis , grid , data type , process (computing) , geographic coordinate system , variables , data mining , orientation (vector space) , data model (gis) , theoretical computer science , algorithm , mathematics , statistics , geography , geometry , artificial intelligence , programming language , cartography , machine learning , mathematical analysis , telecommunications , frame (networking) , pure mathematics
In Part 1 of this paper, the concept of a field variable was described. In Part 2, the way in which a field variable might be specified is outlined. Field variables can be declared like other data types in any standard computing language. Specifications of field variables must include several special properties which are used to express the relationship between the physical field and the discrete data model. Field variable properties determine how the spatial data can be manipulated. For example, specifying a cellgrid spatial data model requires information about grid orientation and origin and the size of cells, while specifying a polygon data model requires information about the minimum distance over which variation is recorded. In either case, this information can be used to select appropriate conversion procedures between spatial data models using similarly specified conversion matrices and rules. The use of field variables has pedagogic as well as practical value. New operations allowed include field functions such as those for determining integrals, slope, and aspect, and reserved variables such as latitude and longitude.