Changes between Version 33 and Version 34 of WKTRaster/SpecificationWorking02


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Timestamp:
Sep 21, 2010, 7:23:09 AM (14 years ago)
Author:
pracine
Comment:

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  • WKTRaster/SpecificationWorking02

    v33 v34  
    3333== '''Objective 2.0.02 - Being able to create a raster as the expression of another raster''' ==
    3434
     35'''ST_MapAlgebra'''
    3536
     37 Returns a one band raster as the mathematical expression of another raster band.
     38
     39 The resulting raster conserve the size, the georeference, the alignment and the SRID of the provided raster. The pixel type of the resulting raster might be specified. An extra nodata value expression, applying only on nodata values, can be provided.
     40
     41 '''Variants'''
     42
     43  First series of variant with band specifier.
     44
     45  1) ST_MapAlgebra(rast raster, band integer, expression text, nodatavalueexpr text, pixeltype text)
     46
     47  2) ST_MapAlgebra(rast raster, band integer, expression text, nodatavalueexpr text)
     48
     49  3) ST_MapAlgebra(rast raster, band integer, expression text, pixeltype text)
     50
     51  4) ST_MapAlgebra(rast raster, band integer, expression text)
     52 
     53  Second series of variant without band specifier.
     54
     55  5) ST_MapAlgebra(rast raster, expression text, nodatavalueexpr text, pixeltype text)
     56
     57  6) ST_MapAlgebra(rast raster, expression text, nodatavalueexpr text)
     58
     59  7) ST_MapAlgebra(rast raster, expression text, pixeltype text)
     60
     61  8) ST_MapAlgebra(rast raster, expression text)
     62 
     63 '''Implementation details'''
     64
     65 Only the first variant should be implemented in C. Others are pl/pgSQL variants.
    3666
    3767----