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Changes between Version 45 and Version 46 of WKTRaster/SpecificationFinal01

Timestamp:: Sep 3, 2010, 1:49:57 PM (14 years ago)
Author:: pracine
Comment:: —

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WKTRaster/SpecificationFinal01

-              v45
+              v46
  '''Variants'''
+) ST_Polygon(raster, integer) -> polygon geometry
+) ST_Polygon(raster) -> polygon geometry -- default to band # 1
+) ST_Polygon(raster) -> polygon geometry -- default to band # 1
  '''Implementation details'''
 …
  '''Variants'''
+) ST_DumpAsPolygons(raster, integer) -> geomval set
+) ST_DumpAsPolygons(raster) -> geomval set -- default to band # 1
+) ST_DumpAsPolygons(raster) -> geomval set -- default to band # 1
  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().
 …
  Returns a set of "geomval" value representing the shared portion of the geometry and the raster band areas sharing a common meaningfull values. The integer parameter is the band number of the raster.
+ This is a set-returning function (SRF). It returns a set of "geomval" representing the point set intersection of the geometry and the areas of the raster sharing a common meaningfull value (NODATA values ARE taken into account). The raster is first polygonised using ST_DumpAsPolygons(raster) and ST_Intersection(geometry, geometry) is then performed between the provided geometry and all the geometries resulting from the polygonisation of the raster.
+ If the geometries do not share any space (are disjoint), then an empty geometry collection is returned.
+ ST_Intersection in conjunction with ST_Intersects is very useful for clipping geometries such as in bounding box, buffer, region queries where you only want to return that portion of a geometry that sits in a country or region of interest.
+ If you only want to compute the intersection between the convex hull of the raster without polygonising it to group of pixels sharing a common value, do:
+  ST_Intersection(ST_ConvexHull(raster), geometry)
+ If you only want to compute the intersection between the shape of the raster without polygonising it to group of pixels sharing a common value, do:
+  ST_Intersection(ST_Polygon(raster), geometry)
  '''Variants'''
 ) ST_Intersection(raster, geometry) -> geometry -- default to band # 1
+) ST_Intersection(raster, geometry) -> geometry
 ) ST_Intersection(geometry, raster, integer) -> geometry -- the integer parameter is the band number of the raster
+) ST_Intersection(geometry, raster) -> geometry -- default to band # 1
+ This is a set-returning function (SRF). It returns a set of "geomval" representing the point set intersection of the geometry and the areas of the raster sharing a common meaningfull value (NODATA values ARE taken into account). The raster is first polygonised using ST_DumpAsPolygons(raster) and ST_Intersection(geometry, geometry) is then performed between the provided geometry and all the geometries resulting from the polygonisation of the raster.
+ If the geometries do not share any space (are disjoint), then an empty geometry collection is returned.
+ ST_Intersection in conjunction with ST_Intersects is very useful for clipping geometries such as in bounding box, buffer, region queries where you only want to return that portion of a geometry that sits in a country or region of interest.
+ If you only want to compute the intersection between the convex hull of the raster without polygonising it to group of pixels sharing a common value, do:
+  ST_Intersection(ST_ConvexHull(raster), geometry)
+ If you only want to compute the intersection between the shape of the raster without polygonising it to group of pixels sharing a common value, do:
+  ST_Intersection(ST_Polygon(raster), geometry)
+) ST_Intersection(geometry, raster) -> geometry
+ Variants 1 and 2 default the band number to 1.
  '''Implementation details'''
 …
 '''ST_SetSRID(raster, integer)'''
+'''ST_SetSRID(raster, integer) -> raster'''
  Sets the spatial reference on the specified raster. This is the same as the ST_SetSRID function working on geometries.
 '''ST_SetPixelSize(raster, pixelsize)'''
  '''Variants'''
 ) ST_SetPixelSize(raster, pixelsize)
 ) ST_SetPixelSize(raster, xsize, ysize)
  Sets the pixel size (cell size) on the specified raster. The base method sets the X and Y pixel size to the same value. Variant 2 sets the pixel sizes to the individually specified x and y sizes.
+'''ST_SetPixelSize(raster, pixelsize) -> raster'''
+ Sets the pixel size (cell size) on the specified raster. The base method sets the X and Y pixel size to the same value.
+ '''Variants'''
+) ST_SetPixelSize(raster, xsize, ysize) -> raster
+ Variant 1 sets the pixel sizes to the individually specified x and y sizes.
 '''ST_SetBandNoDataValue(raster, band, value)'''
 …
  Sets the value that corresponds to NODATA in the given raster's band.
 '''ST_SetGeoReference(raster, georef)'''
  '''Variants'''
 ) ST_SetGeoReference(raster, georef, format)
 ) ST_SetGeoReference(raster, georef)
  Sets the georeference fields of the raster (pixel size, skew, upper left location) all in one pass. The 'format' parameter is optional, and defaults to 'GDAL' georeference format if it is not specified.
+'''ST_SetGeoReference(raster, georef text, format text) -> raster'''
+ Sets all the georeference fields of the raster (pixelsize X, pixelsize Y, skew X, skew Y, upper left X, upper left Y) using the specified string. Format might be 'GDAL' or 'ESRI'. The GDAL format expect the upper left X and Y to be the upperleft corner of the upper left pixel and the ESRI format expect the upper left X and Y to be the upperleft center of the upper left pixel.
+ '''Variants'''
+) ST_SetGeoReference(raster, georef text) -> raster
+ Variant 1 default format to 'GDAL'.
  If this function does not receive a georeference string with 6 parameters (or if one of the parameters is not numeric), it raises an exception "st_setgeoreference requires a string with 6 floating point values". If this method receives a NULL raster, it does nothing, and returns a NULL raster.
 '''ST_SetSkew(raster, skewx, skewy)'''
  '''Variants'''
 ) ST_SetSkew(raster, skewx, skewy)
 ) ST_SetSkew(raster, skew)
  Set the skewx and the skewy of the raster's georeference. Variant 2 sets the X and Y skew to the same value.
 '''ST_SetUpperLeft(raster, left, top)'''
+'''ST_SetSkew(raster, skewx, skewy) -> raster'''
+ Set the skewx and the skewy of the raster's georeference.
+ '''Variants'''
+) ST_SetSkew(raster, skew)
+ Variant 1 sets the X and Y skew to the same value.
+'''ST_SetUpperLeft(raster, left, top) -> raster'''
  Sets the location of the upper left pixel (cell). The base method sets the X and Y coordinates to the individually specified left and top coordinates.
 …
 '''ST_BandPath(raster, band) -> string'''
  Return the path of the filesystem raster associated with this band. The band does not contain any pixel value.
+ Returns the path of the filesystem raster associated with this band. The band does not contain any pixel value.
 ----
 …
 '''ST_BandHasNoDataValue(raster, band)'''
  Return TRUE if the value stored as a NODATA value for the band must be interpreted as a real NODATA value.
+ Returns TRUE if the value stored as a NODATA value for the band must be interpreted as a real NODATA value.
 '''ST_SetBandHasNoDataValue(raster, band)'''
 …
 '''ST_Value(raster, band, x, y)'''
 Return the value (as a double precision number) of the pixel located at x, y in the specified band.
+ Returns the value (as a double precision number) of the pixel located at x, y in the specified band.
 '''ST_SetValue(raster, band, x, y, val)'''
 Set the value of the pixel located at x, y in the specified band. Return the modified raster.
+ Set the value of the pixel located at x, y in the specified band. Returns the modified raster.
 ----