Take the 2-minute tour ×
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It's 100% free, no registration required.

I'm having some difficulty understanding the error I am getting from my mapserver/postgis program. I have the following map file:

MAP     # start of map file

        NAME "sample"
        EXTENT  82299.5 5002.78 655979.76 657599.55
        SIZE 800 400


        LAYER   # layer info
                CONNECTIONTYPE postgis
                NAME "roads
                CONNECTION "user=username 
                password=**** dbname=databasename host=hostdb.com port=5432" 
                DATA "the_geom from public.\"MLSOA\""
                STATUS ON
                TYPE LINE
                                COLOR 0 0 0
END     # end of map file

I then call this using the following command:


which gives me the following error:

msDrawMap(): Image handling error. Failed to draw layer named 'roads'. 
sPostGISLayerWhichShapes(): Query error. Error (ERROR: find_srid() 
- couldnt find the corresponding SRID - is the geometry registered in the 
GEOMETRY_COLUMNS table? Is there an uppercase/lowercase missmatch? ) 
executing query: select encode(ST_AsBinary(ST_Force_2D("the_geom"),'NDR'),'hex') 
as geom,"oid" from public."MLSOA" where the_geom && GeomFromText
('POLYGON((-180.225563909774 -90,-180.225563909774 
90,180.225563909774 90,180.225563909774 -90,-180.225563909774 

I asked a question on GIS.SE earlier today about a problem I was having connecting to the DB, and @unicoletti helpfully solved my earlier problem about the database name. However I have now tried all the options that I understand could be causing this current error and have not figured out the problem.

Things that I have tried:

  1. Checking that the the table is registered in GEOMETRY_COLUMNS (it is, as I could not manually add it as it was there already).
  2. Adding in a projection to the Mapserver file
  3. Running SELECT Probe_Geometry_Columns() to update GEOMETRY_COLUMNS
  4. Creating an index using the following command: CREATE INDEX table_the_geom ON "MLSOA" USING GIST ( the_geom ); CLUSTER table_the_geom ON public."MLSOA";

Are there any other things that could be causing this error? I'm using PostGreSQL 8.3, PostGIS 1.5.3 and Mapserver 6.0.1. and these programs are all running on a Linux server.

share|improve this question
glad you solved it! –  unicoletti Oct 19 '11 at 19:16
add comment

1 Answer

up vote 4 down vote accepted

The sub-query that throws the error (Find_SRID) is incorrect:

select find_srid('','public."MLSOA"','the_geom')

Do you really need to specify the public schema in your query? Normally this is part of your search_path variable, so you normally don't need it. Try using this in your MAP file:

DATA "the_geom from \"MLSOA\" using unique gid using srid=27700"

(Note: update gid with your integer/serial primary key column name, if it is different)

share|improve this answer
Thanks Mike, that worked. You are correct, I did not need public in my query. –  djq Oct 19 '11 at 19:13
add comment

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.