Changes between Version 17 and Version 18 of WKTRaster/SpecificationWorking02


Ignore:
Timestamp:
08/27/10 13:35:00 (14 years ago)
Author:
pracine
Comment:

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  • WKTRaster/SpecificationWorking02

    v17 v18  
    2121'''ST_Intersects(raster, raster)'''[[BR]]
    2222'''ST_AsRaster(geometry, pixelsize) -> raster'''[[BR]]
    23 '''ST_Intersection(geometry, raster, band) -> raster'''
     23'''ST_Intersection(geometry, val, raster, band) -> raster'''
    2424
    25  Variant 1: ST_Intersection(geometry, val, raster, band) -> raster with the same metadatada as the provided raster. Non intersecting pixels are filled with nodata values.
     25 The first series of variant return a raster having the same extent as the provided raster.
    2626
    27  Variant 2: ST_Intersection(geometry, val, raster, band, 'TRIM') -> raster with the same metadatada as the provided raster but the extent is reduced to the geometry extent. Non intersecting pixels are filled with nodata values.
     27  Variant 1: ST_Intersection(geometry, val, raster, band) -> raster
    2828
    29  Rasterize the geometry as a new raster (ST_AsRaster(geometry, pixeltype, val, nodataval, raster)) and then copy only pixels for which both raster bands have a value. Optionally trim the raster to withvalue extent.
     29  Variant 2: ST_Intersection(raster, band, geometry, val) -> raster
     30
     31  Variant 3: ST_Intersection(geometry, val, raster) -> raster
     32
     33  Variant 4: ST_Intersection(raster, geometry, val) -> raster
     34
     35 The second series of variant return a raster having the minimal extent.
     36
     37  Variant 5: ST_Intersection(geometry, val, raster, band, 'TRIM') -> raster
     38
     39  Variant 6: ST_Intersection(raster, band, geometry, val, 'TRIM') -> raster
     40
     41  Variant 7: ST_Intersection(geometry, val, raster, 'TRIM') -> raster
     42
     43  Variant 8: ST_Intersection(raster, geometry, val, 'TRIM') -> raster
     44
     45 Return a two bands raster the first band containing only the pixels from the provided raster intersecting with the geometry and the second band containing the same area filled with the provided value. Non intersecting pixels are filled with nodata values. Variant 1 return a raster having the same extent as the provided raster. Variant 3, 4, 7 and 8 defaults the band number to 1. Variant 5 to 8 "trim" or "crop" the raster to the withvalue extent (removing extra nodata value pixels surrounding the extent of the resulting withvalue extent).
     46
     47
     48 Implementation details
     49
     50 Rasterize the geometry as a new raster (ST_AsRaster(geometry, pixeltype, val, nodataval, raster)) and then copy only pixels for which both raster bands have a value.
     51 Should be implemented as a wrapper around ST_MapAlgebra after rasterizing the geometry to a raster having the same alignment as the raster.
    3052
    3153----