EPSG:CODE

How to Add a Custom CRS to PostGIS

PostGIS stores coordinate reference systems in the spatial_ref_sys table. To add a new CRS, simply run an INSERT query against this table.

Step 1: Check If It Already Exists

SQL 
SELECT srid, proj4text FROM spatial_ref_sys WHERE srid = 5255;

If no result is returned, you need to add the CRS definition.

Step 2: Insert the CRS Definition

SQL 
INSERT INTO spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext)
VALUES (
  5255,
  'EPSG',
  5255,
  '+proj=tmerc +lat_0=0 +lon_0=33 +k=1 +x_0=500000 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs +type=crs',
  'PROJCS["TUREF / TM33",GEOGCS["TUREF",DATUM["Turkish_National_Reference_Frame",SPHEROID["GRS 1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",33],PARAMETER["scale_factor",1],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],UNIT["metre",1]]'
);

Search for any EPSG code on the home page and copy the SQL from the PostGIS tab.

Step 3: Verify

SQL 
SELECT srid, auth_name, proj4text FROM spatial_ref_sys WHERE srid = 5255;

Updating an Existing Definition

To update an existing CRS:

SQL 
UPDATE spatial_ref_sys
SET proj4text = '+proj=tmerc +lat_0=0 +lon_0=33 +k=1 +x_0=500000 +y_0=0 +ellps=GRS80 +units=m +no_defs'
WHERE srid = 5255;

Notes