[postgis-devel] [PostGIS] #2105: [raster] ST_Transform needs an alignment parameter

[PostGIS]

#2105: [raster] ST_Transform needs an alignment parameter
-------------------------+--------------------------------------------------
 Reporter:  dustymugs    |       Owner:  dustymugs    
     Type:  enhancement  |      Status:  new          
 Priority:  medium       |   Milestone:  PostGIS 2.1.0
Component:  raster       |     Version:  trunk        
 Keywords:               |  
-------------------------+--------------------------------------------------
 A significant limitation of ST_Transform(raster) is that if you were to
 run ST_Transform(raster) on a table of aligned rasters, the output
 probably is not aligned...

 {{{
 SELECT
 ST_Transform(rast, 4326)
 FROM my_aligned_rasters_table
 }}}

 What is needed is an alignment parameter (a reference raster that the
 transformed rasters are aligned to).

 {{{
 WITH foo AS (
 SELECT
 ST_Transform(rast, 4326) AS alignto
 FROM my_aligned_rasters_table
 WHERE rid = 1
 )
 SELECT
 ST_Transform(rast, alignto)
 FROM my_aligned_rasters_table
 CROSS JOIN foo
 }}}

 Since the reference raster already has the desired SRID, keeping the SRID
 parameter is redundant and can be removed...

 {{{
 CREATE OR REPLACE FUNCTION st_transform(
         rast raster,
         alignto raster,
         algorithm text DEFAULT 'NearestNeighbour', maxerr double precision
 DEFAULT 0.125
 )
 }}}

-- 
Ticket URL: <http://trac.osgeo.org/postgis/ticket/2105>
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