Changes between Version 26 and Version 27 of WKTRaster/SpecificationFinal01

Timestamp:

08/27/10 11:57:28 (14 years ago)

Author:

pracine

Comment:

--

WKTRaster/SpecificationFinal01

@@ -128 +128 @@
  This function replaces ST_Raster_to_box2d() and should be used for the "raster AS box2d" cast. It should also be used instead of ST_raster_envelope() when creating indexes in gdal2wktraster.py (to be tested).
 
+'''ST_ConvexHull(raster) -> polygon geometry''' - Returns the minimum convex geometry that encloses every pixel from the raster. 
+
+ The resulting polygon DOES NOT TAKE the NODATA values into account. The resulting polygon enclose every pixel, even those containing NODATA values. The resulting polygon can be rotated or not depending on the rotation of the raster. If the raster is not rotated ST_ConvexHull(geometry) is (almost) equivalent to ST_Envelope(raster) (ST_Envelope floor the coordinates and hence add a little buffer around the raster).
+
+ '''Implementation details'''
+
+ This function is actually already implemented by the 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
+
 '''ST_Envelope(raster) -> polygon geometry''' - Returns the minimum bounding box for the supplied raster, as a geometry. 
 
@@ -143 +151 @@
 [[Image(WKTRasterEnvelopeConvexHullAndPolygon.gif)]]
 
-'''ST_ConvexHull(raster) -> polygon geometry''' - Returns the minimum convex geometry that encloses every pixel from the raster. 
-
- The resulting polygon DOES NOT TAKE the NODATA values into account. The resulting polygon enclose every pixel, even those containing NODATA values. The resulting polygon can be rotated or not depending on the rotation of the raster. If the raster is not rotated ST_ConvexHull(geometry) is (almost) equivalent to ST_Envelope(raster) (ST_Envelope floor the coordinates and hence add a little buffer around the raster).
-
- '''Implementation details'''
-
- This function is actually already implemented by the 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
 
 '''ST_Polygon(raster, integer) -> polygon geometry''' - Returns a geometry encomparsing every pixel having a significant value (different than the NODATA value) for the provided band.