Changes between Version 66 and Version 67 of WKTRaster/SpecificationWorking01

Timestamp:

12/16/09 12:19:54 (15 years ago)

Author:

pracine

Comment:

—

WKTRaster/SpecificationWorking01

@@ -203 +203 @@
 
  The only difference with ST_Box2D(raster) is that ST_Envelope(raster) returns a geometry, not a BOX2D.
-
- This function should replace the actual ST_raster_envelope() function which is wrongly named.
  
  There is also a ticket (#348) related to this function: http://trac.osgeo.org/postgis/ticket/348
@@ -214 +212 @@
  A ST_ConvexHull(raster, 'WITHNODATA') variant SHOULD NOT TAKE the NODATA value into account. It generally returns a square or rectangle polygon that can be rotated or not depending on the rotation of the raster. If the raster is not rotated ST_ConvexHull(geometry, 'WITHNODATA') is (almost) equivalent to ST_Envelope(raster).
 
+ This variant should replace the actual ST_raster_envelope() function which is wrongly named.
+
+
  '''Implementation details'''
 
- The first variant ST_ConvexHull(raster) could be roughly implemented with a SQL or PL/pgSQL function looking like 'SELECT '
+ The first variant (taking NODATA values into account) ST_ConvexHull(raster) could be roughly implemented with a SQL or PL/pgSQL function looking like 'SELECT ST_BuildArea(ST_ExteriorRing(ST_Shape(raster)))'
+
+ The second variant (not taking NODATA values into account) is 
 
 '''ST_Shape(raster) -> polygon geometry''' - Returns a geometry encomparsing every pixel having a significant value (different than the NODATA value).