[mapserver-users] Raster alignment problem

[Graham Carlyle]

Hi

I'm trying to render some maps using Mapserver that contain both vector 
and raster data. However the raster data doesn't consistently align with 
the vector data at different zoom levels.

I've looked at the combination of raster and vector in qgis 11.0 and it 
displays fine.

When rendering with Mapserver 5.2.0 the raster image positions 
differently at different zoom levels. I've also recreated the problem 
using a simple test raster of alternating values which I created 
programmatically with libgdal.

Does anyone have any suggestions as to what I might be doing wrong or 
how I might debug my problem further? I'm very doubtful that its a bug 
in mapserver as surely other people would have encountered this.

I'm using the PROJECTION '+proj=longlat +ellps=WGS84 +datum=WGS84 
+no_defs' in the map file for both raster and vector

gdalinfo on the test raster:
Driver: GTiff/GeoTIFF
Files: raster/test_qs.tif
Size is 180, 180
Coordinate System is:
GEOGCS["WGS 84",
     DATUM["WGS_1984",
         SPHEROID["WGS 84",6378137,298.2572235629972,
             AUTHORITY["EPSG","7030"]],
         AUTHORITY["EPSG","6326"]],
     PRIMEM["Greenwich",0],
     UNIT["degree",0.0174532925199433],
     AUTHORITY["EPSG","4326"]]
Origin = (-90.000000000000000,90.000000000000000)
Pixel Size = (1.000000000000000,-1.000000000000000)
Metadata:
   AREA_OR_POINT=Area
Image Structure Metadata:
   INTERLEAVE=BAND
Corner Coordinates:
Upper Left  ( -90.0000000,  90.0000000) ( 90d 0'0.00"W, 90d 0'0.00"N)
Lower Left  ( -90.0000000, -90.0000000) ( 90d 0'0.00"W, 90d 0'0.00"S)
Upper Right (  90.0000000,  90.0000000) ( 90d 0'0.00"E, 90d 0'0.00"N)
Lower Right (  90.0000000, -90.0000000) ( 90d 0'0.00"E, 90d 0'0.00"S)
Center      (   0.0000000,   0.0000000) (  0d 0'0.01"E,  0d 0'0.01"N)
Band 1 Block=180x45 Type=Byte, ColorInterp=Gray

The shape file prj is...
GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]]

thanks,
Graham