[Mapserver-users] Large Raster files
warmerdam at pobox.com
Tue May 18 13:11:17 EDT 2004
> I have a question regarding the relationship between PROJECTION and
> EXTENT for the display of layers in the mapfile (mapserve src 4.02 and
> the new 4.2beta) I have managed to get a custom region working using the
> mapderve cgi tutorial files as a start. I have successfully displayed
> and tiled natural color ortho tiffs in EPSG:32115 (NY East state plane),
> and I have succeeded with a UTM location that displays shape files in
> EPSG:26918 (UTM 18N NAD83 GRS80).
> I have downloaded 302 world-file-referenced tiffs with the 1:24000 scale
> topo info for NYS. These are in EPSG:26918 (UTM 18NnAD83 GRS80) and the
> extents, coordinate system and mapping have been verified in my GIS
> program (grass 5.03). These files will not display, neither as single
> maps nor as a tiled map, even though the shapefile for the TILEINDEX
> (with the exact same coord parameters) displays just fine (I even got a
> county line shapefile map in latlong coordinates to plot properly on the
> UTM basemap). No errors in the logs. I used .tfw and .wld and internal
> GeoTiff (gdal_translated) files all with the same null result.
> I have searched and read the posts on related problems, and it seems I
> have considered al the possibilities listed. I tried a gdalwarp into
> state plane (tiff output) coordinates to see if I could "TRANSFORM" it
> onto the base EPSG:26918 map, but failed to get anything more than the
> blank map frame.
> Is there something about UTM and EPSG I am missing, at least as they
> concern mapserver?
Common problems in this sort of configuration include:
o Path in the tile index is not absolute. They don't have to be absolute, but
it can be tricky to use proper relative paths in a web environment. If files
are not found, MapServer will often just quietly ignore the fact.
o Some sort of mixup with the extents. Are the extents in UTM 18 as well?
If the tileindex plots properly this is likely not the problem.
o Using a MapServer without appropriate format support. For instance, if you
don't have GDAL support you may not be able to display some formats of TIFF.
o Getting the wrong driver. Old MapServers (4.0? at least in 3.x) sometimes
would use the built-in TIFF driver instead of GDAL. The built-in TIFF
driver only suppose a few variations of TIFF file organization.
My suggestions for debugging:
o Turn on debugging and review debug messages. Set the "DEBUG ON" line
in the MAP object, and in the tileindexed raster layer object. You should
see at least a few debug messages even if things are working just fine.
o Test at the commandline with shp2img program (and debugging enabled).
o Turn on GDAL debugging when testing with shp2img by setting the environment
variable GDAL_DEBUG to ON. You should see debug messages about each TIFF
file that is actually opened.
I set the clouds in motion - turn up | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | Geospatial Programmer for Rent
More information about the mapserver-users