[postgis-tickets] [PostGIS] #2248: ST_AsGDALRaster Missing Spatial Reference

[PostGIS]

#2248: ST_AsGDALRaster Missing Spatial Reference
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 Reporter:  digimap2k  |       Owner:  pramsey
     Type:  defect     |      Status:  new    
 Priority:  medium     |   Milestone:         
Component:  postgis    |     Version:  2.0.x  
 Keywords:             |  
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Comment(by digimap2k):

 OK so for anyone reading this looking for a solution my conclusion are the
 following:

 It looks like the construction of output files from rasters through
 ST_AsPng|Tiff|GDALRaster don't include the spatial reference system. This
 in itself is perhaps not that suprising as most folk would most likely be
 constructing some sort of transformed image as the endpoint in the
 processing, perhaps for a map server. The information is clearly in there
 as gdalinfo on the entire table does correctly extract and report the
 PROJ_CS.

 So the workaround:

 First up if you don't care about the PROJ_CS then do nothing. If you want
 to pull rasters as GeoTiffs for input into another GIS processing stage
 then you need to push these into the files manually. What I do to
 workaround this is in Qt C++ using GDAL/OGR is...

 1) Grab the files using ST_AsGDALRaster(rast,'GTiff')
 2) Grab the SRID of the raster in it's EPSG integer code from the database
 using ST_SRID.
 3) Make the WKT for the spatial reference using OGR, I guess you could
 also do this using the spatial ref sys table in postgres.
 4) Construct a GDALDatasetH from the binary raster data.
 5) Apply the WKT spatial reference.
 6) Save to file to check it and gdalinfo is all as should be.

 Clearly the fix needed in postGIS is to push the spatial reference
 directly into the file in the first place. Pretty sure it's not me and
 generally failing to do this as gdalinfo on the bzipped results from the
 postgis test runs also shows no valid PROJ_CS in any of the test files.

 Hope that helps someone ;-)

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/2248#comment:5>
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