Question
How do you check the CRS (SRID) of Spatial data in a PostGIS database?
Answer
PGAdmin provides a SQL Query window which allows you to write attribute, spatial and geometry queries for your data. Open the SQL window and use the following SQL Statement to check the Coordinate Reference System (CRS) of your data. Replacing the table_name and selecting the geometry column as required.
In the example above the CRS (or SRID) is set to zero. This is common if you have used the PGAdmin Shapefile Importer tool and have forgotten to assign the CRS (SRID) in the import options.
If you wish to set the CRS, you can either import the Shapefile again, or use the SQL query below to update the CRS (SRID) of your spatial data, using the numeric value, for example 27700 for British National Grid.
Once the CRS (SRID) has been updated, you can now check the new CRS (SRID) by running the original query.
