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I am able to import raster data easily into the database and view it through QGIS. However, I am unable to view the raster layer in Arcgis. Now I want to know how to create a table with a reference to raster files outside the datbaase. However, there isn't much discuss or example with regards to how it can be done. I want to see its benefits given that raster layers can be shared across various applications.

Please share your knowledge on this?

Thanks in advance.

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3 Answers 3

Use the -R flag when using raster2pgsql to add the raster into PostGIS. The -R flag indicates that the raster will be stored out-of-db. All of the raster analysis functions in PostGIS will work but not the write functions, e.g. set pixel values, add bands. In my limited testing, the performance of out-of-db rasters is slower than in-db.

http://postgis.refractions.net/documentation/manual-svn/using_raster.xml.html#RT_Raster_Loader

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Thank you. Is it possible to view the table with arcmap. I could not see it because of the postgis raster data type. I thought since it only maintance a reference to the images outside the database it might be just a geometry type. Any suggestion –  GISTECH Jul 26 '12 at 16:44
    
If you're using out-of-db rasters, you don't need ArcGIS to call PostGIS. Just point ArcGIS directly to the raster files themselves. –  dustymugs Jul 27 '12 at 22:56
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In my work I store raster as a varchar pointing to the raster name, I use Django Framework (python) and as an example the procedure that I use is the following:

1) Have common path for the files ex: RASTER_PATH=/home/rasters
2) In the moment of creation the raster gets a hash name with py's hashlib (ex. 2d9e74148425752af7587c5b419542cb54480c49).
3) Only the name is stored in the DB. The file is stored in the RASTER_PATH.
4) When I need the raster I join the path with the name.
5) That's very versatile, I use the same name to create stores in GeoServer. And to create (hashed) layer names.

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Thanks for your information pablo.I need to use ArcGIS. So, I am exploring better way of accessing raster data. –  GISTECH Jul 26 '12 at 17:44
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QGIS uses the GDAL PostGIS Raster driver to display the data. I know it has a problem (I'm the developer of the driver). Actually working on it. Results expected before September.

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