there's no subpixel positioning for rasters by default, so for coarse rasters like the one you're showing, you can force that by adding a PROCESSING "resample=nearest" to your raster layer
thomas On Thu, Oct 9, 2008 at 16:20, Graham Carlyle <[EMAIL PROTECTED]> wrote: > 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 > _______________________________________________ > mapserver-users mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/mapserver-users > _______________________________________________ mapserver-users mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/mapserver-users
