From: Regina Obe Date: Mon, 11 Nov 2013 17:42:59 +0000 (+0000) Subject: #2541 document = and ~= raster operators X-Git-Tag: 2.2.0rc1~1295 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7d70f40e44d9201afa53a23107efab568db225d6;p=postgis #2541 document = and ~= raster operators git-svn-id: http://svn.osgeo.org/postgis/trunk@12120 b70326c6-7e19-0410-871a-916f4a2858ee --- diff --git a/doc/reference_raster.xml b/doc/reference_raster.xml index f6d4a018d..cebba247e 100644 --- a/doc/reference_raster.xml +++ b/doc/reference_raster.xml @@ -12393,6 +12393,107 @@ a_rid | b_rid | overleft + + + + = + + Returns TRUE if A's bounding box is the same as B's. Uses double precision bounding box. + + + + + + boolean = + + + raster + + A + + + + raster + + B + + + + + + + Description + + The = operator returns TRUE if the bounding box of raster A + is the same as the bounding box of raster B. PostgreSQL uses the =, <, and > operators defined for rasters to + perform internal orderings and comparison of rasters (ie. in a GROUP BY or ORDER BY clause). + + This operand will NOT make use of any indexes that may be available on the + rasters. Use instead. This operator exists mostly so one can group by the raster column. + + Availability: 2.1.0 + + + + + See Also + + + + + + + + ~= + + Returns TRUE if A's bounding box is the same as B's. + + + + + + boolean ~= + + + raster + + A + + + + raster + + B + + + + + + + Description + + The ~= operator returns TRUE if the bounding box of raster A + is the same as the bounding box of raster B. + + This operand will make use of any indexes that may be available on the + rasters. + + Availability: 2.0.0 + + + + + Examples + Very useful usecase is for taking two sets of single band rasters that are of the same chunk but represent different themes and creating a multi-band raster +SELECT ST_AddBand(prec.rast, alt.rast) As new_rast + FROM prec INNER JOIN alt ON (prec.rast ~= alt.rast); + + + + See Also + , + +