From 44a89cf32cb560bdb9f10c7309f1f95f5da27474 Mon Sep 17 00:00:00 2001 From: Bborie Park Date: Tue, 3 Jul 2012 22:30:30 +0000 Subject: [PATCH] Addition of notes differentiating ST_DumpPolygons and ST_PixelsAsPolygons git-svn-id: http://svn.osgeo.org/postgis/trunk@10026 b70326c6-7e19-0410-871a-916f4a2858ee --- doc/reference_raster.xml | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/doc/reference_raster.xml b/doc/reference_raster.xml index 1d6ad7990..2df1517aa 100644 --- a/doc/reference_raster.xml +++ b/doc/reference_raster.xml @@ -3049,6 +3049,12 @@ WHERE rid=2; Returns the geometry that bounds every pixel of a raster band along with the value (double precision), the X and the Y raster coordinates (integers) of each pixel. + + + ST_PixelAsPolygons returns one geometry for every pixel. This is different than ST_DumpAsPolygons where each geometry represents one or more pixels with the same pixel value. + + + @@ -6244,6 +6250,11 @@ FROM (SELECT ST_SetRotation(rast, 0.1, 0.1) As rast Availability: Requires GDAL 1.7 or higher. If there is a no data value set for a band, pixels with that value will not be returned. If you only care about count of pixels with a given value in a raster, it is faster to use . + + + This is different than ST_PixelAsPolygons where one geometry is returned for each pixel regardless of pixel value. + + -- 2.50.1