Error while rendering a layer from postgresql in mapserver

Question

I got a point layer into QGIS from postgresql database. After this I used a plugin to export it to a map file.After exporting the following is the starting of the map file.

 NAME "QGIS-MAP"
 # Map image size
 EXTENT 59.396660 7.316000 105.983338 35.204001
 Imagecolor 255 255 255
 SIZE 100 100
 UNITS meters
 Imagetype jpeg
 FONTSET 'C:\ms4w\Apache\htdocs\fontset.txt'
PROJECTION
'proj=longlat'
'datum=WGS84'
'no_defs'

Now when I change the size parameter to 600 400 and the units to dd. It gives me the following error while rendering the layer.

msDrawMap(): Image handling error. Failed to draw layer named 'growth_1'. msPostGISLayerWhichShapes(): Query error. Error executing query: ERROR: column "%growth_1_id%" does not exist LINE 1: ...ary(ST_Force_2D("the_geom"),'NDR'),'hex') as geom,"%growth_1... ^

First of all I am not sure why is it taking units as meter.But if I dont change it to dd , the legends come up but the layer is not rendered. Also the extent which i get is in the range of 100's and not the one which I have defined.

Could someone tell me where is this thing going wrong.

enter image description here

Answer 1

I assume this relates to Why does Mapserver throw "msQueryByPoint(): Search returned no results."? ? If so and as far as the error you are getting, I suspect its because you have not defined (does not exist?) a pk column in the postgis layer. Your growth_1 layer should include the USING UNIQUE in the DATA keyword e.g.:

CONNECTIONTYPE postgis
CONNECTION "dbname='postgis' host=localhost port=5432 user='postgres' password='xxxxxxx' sslmode=disable"
DATA 'the_geom FROM "growth_1" USING srid=4326 USING unique [your_pk_column]'

I am not sure, but I pressume that if you don't define the unique column mapserver will assume its called [layer_name]_id and this is why you are getting this error.

Also, have a look at the mapserver documentation here and here

• SNT: I did try the unique column after I posted the question, but it doesnt seem to help my case: CONNECTION "dbname='postgis' host=localhost port=5432 user='postgres' password='xxxxxxx' sslmode=disable" DATA "the_geom FROM growth_1 USING unique oid USING srid=4326"
• mapoholic: Are you sure OID exists in the table? I think OID is one of Postgis system fields. I would suggest creating a new unique column, call it-say- gid and then define this in the mapfile. i.e. ALTER TABLE xyz > > ADD COLUMN gid serial; I think I remember something about OIDs that are not supposed to be defined as the unique key in the mapfile.
• SNT: I added a column named as oid .Now what happens is I get the query table output with field names but not the values. I shall add the screenshot of the query result.
• mapoholic: You have asked this on a different question Senthil. Do you still get the error for THIS question?
• SNT: I think this thread should be closed.I dont get this error any more . I get a new error now.