Changes between Version 30 and Version 31 of WKTRaster/SpecificationFinal01


Ignore:
Timestamp:
Aug 27, 2010, 12:22:05 PM (14 years ago)
Author:
pracine
Comment:

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  • WKTRaster/SpecificationFinal01

    v30 v31  
    170170 Variant 1: ST_DumpAsPolygons(raster) -> geomval set -- default to band # 1
    171171
    172  This function should be used with precaution on raster with float pixel type as it could return one "geomval" (or polygon) per pixel. This kind of raster should be reclassified (using the planned ST_Reclassify(raster,...) function) before using ST_DumpAsPolygons().
     172 This function should be used with precaution on raster with float pixel type as it could return one "geomval" (or polygon) per pixel. This kind of raster should be reclassified (using the planned ST_Reclass(raster,...) function) before using ST_DumpAsPolygons().
    173173
    174174 '''Implementation details'''
    … …  
    193193'''DumpAsWKTPolygons(raster, integer) -> wktgeomval set''' - Returns a set of "geomval" value, one for each group of pixel sharing the same value for the provided band.
    194194
    195  Variant 1: DumpAsWKTPolygons(raster) -> wktgeomval set -- default to band # 1
    196 
    197195 This is a set-returning function (SRF). A "wktgeomval " value is a complex type composed of a the wkt representation of a geometry (one for each group of pixel sharing the same value) and the value associated with this geometry. These values are always returned as a value of type double precision. The shape of each polygon follow pixels edges. Areas with NODATA values are not included in the resulting set.
    198196
    199  This function should be used with precaution on raster with float pixel type as it could return one "geomval" (or polygon) per pixel. This kind of raster should be reclassified (using the planned ST_Reclassify(raster,...) function) before using DumpAsWKTPolygons().
     197 This function should be used with precaution on raster with float pixel type as it could return one "geomval" (or polygon) per pixel. This kind of raster should be reclassified (using the planned ST_Reclass(raster,...) function) before using DumpAsWKTPolygons().
    200198
    201199 DumpAsWKTPolygons() should not be used directly. Use ST_DumpAsPolygons() instead.