Returns blank (all heights 0) 16 bit geotiff

[nbarker@…]

Using MapServer 4.4.1, where the native format of the global gtopo30 is
wgs84(LL) making a request 
http://wms.npagroup.com/cgi-bin/mapserv?REQUEST=GetCoverage&COVERAGE=gtopo30&SERVICE=WCS&map=/var/www/html/wcs/gtopo30/gtopo30.map&FORMAT=GEOTIFF_INT16&CRS=EPSG:32613&BBOX=447300.0,4356840.000,686460.0,4572000.0&RESX=60.0&RESY=60.0
so that the data has to be reprojected results in a blank image.

Requesting the data in its native format (EPSG:4326) works fine.

[sdlime]

I'm sorry there's a problem, but at least someone is using WCS! Any chance of 
posting the mapfile and where to get the data?

Steve

[nbarker@…]

Quite a few are using the WCS in the UK, it is the only WCS that can use 16 bit
geotiff to serve DEMs.  

Speaking to our provider he as placed ETOPO data on an FTP server (details
below), the map file is for GTOPO30 as below.  Any help would be appreciated.

MAP
  NAME 'GTOPO30'
  SHAPEPATH '/var/www/html/wcs/data'

  IMAGETYPE PNG

  OUTPUTFORMAT
    NAME GEOTIFF_INT16
    DRIVER "GDAL/GTiff"
    IMAGEMODE INT16
  END

  OUTPUTFORMAT
    NAME GEOTIFF_RGB
    DRIVER "GDAL/GTiff"
    IMAGEMODE RGB
  END

  WEB
    METADATA
      "wcs_label" "NPA WCS Server"
      "wcs_keywordlist" "WCS,GTOPO30"
#      "wcs_onlineresource" "http://www.npagroup.com"
    END
    IMAGEURL "/tmp/"
    IMAGEPATH "/var/www/html/tmp/"
  END

  LAYER
    NAME "gtopo30"
    STATUS OFF
    TYPE RASTER
    PROCESSING "SCALE=AUTO"
    METADATA
      wcs_label "Global GTOPO30 coverage"
      ows_srs   "EPSG:4326"
      ows_extent "-180 -90 180 90"
      wcs_resolution "0.0083 0.0083"
      wcs_formats "GEOTIFF_INT16"
      wcs_nativeformat "raw binary"
    END
    DUMP TRUE
    DATA '/var/www/html/wcs/gtopo30/gtopo30.tif'
  END
END


server ftp.npagroup.com

login as npa
password is crockham

(note these are effectively an anonymous login but we don't allow 
true anonymous logins)

look in the "tim" directory

Thanks

[fwarmerdam]

Norman, 

I appologise for not having dealt with this issue earlier.  The base problem is
that you didn't define a projection definition using the PROJECTION object for
your raster (ETOPO) layer, so mapserver didn't know how to reproject the image.
I would add that generating non-square pixels goes through the same transformation
mechanism as reprojecting, so you need valid projection definitions for it to
work.

Add the following on your layer and it should work:

    PROJECTION
      "init=epsg:4326"
    END

PS. while debugging this problem I fixed a couple bugs in the WCS code
resulting in mapserver issued errors not getting returned as WCS exceptions.

However, your case would still not generate because it assumes that your
layer of data is in whatever projection the map is.  The map projection
is set by the CRS= option in your WCS request.  So by default your lat/long
bounds are not transformed to UTM and so the data appears to not fall in the
request region.  Hence you get all zeros back. 

Feel free to reopen if you can't get it working.

Once again, I appologise for not following up on this much sooner.  

[nbarker@…]

I have made the changes and I still get zeros back, the map file is pasted
below, and the request is
http://huby/cgi-bin/test?request=GetCoverage&Service=WCS&Coverage=test_Pressure&Version=1.0.0&FORMAT=GTIFF_FLOAT&RESX=1.25&RESY=1.12122015953064&CRS=EPSG:4326

unfortunately this is on an internal server.  Is there anything else I can do to
check this?  The base files are geotiff.

Many thanks


MAP
    NAME 'ADMIN NetCDF_WCS'
	EXTENT -180 -90 180 90
    SIZE 500 400
	UNITS dd
    SHAPEPATH '/var/www/html/WCS/'
	IMAGETYPE PNG
	
	OUTPUTFORMAT
		NAME GTIFF_FLOAT
		DRIVER 'GDAL/GTiff'
		MIMETYPE 'image/tiff'
		IMAGEMODE FLOAT32
		EXTENSION 'tif'
	END
	
	WEB
		METADATA
		    'wcs_label' 'WCS Server'
		    'wcs_keywordlist' 'WCS, netcdf'
		END
		IMAGEURL '/tmp/'
		IMAGEPATH '/var/www/html/tmp/'
	END
	
    LAYER
        NAME 'testPressure_idx'
        TYPE TILEINDEX
        DATA 'test/Pressure/dIndex'
        FILTERITEM 'time'
        FILTER '%time%'
    END
                    
    LAYER
        NAME 'test_Pressure'
        STATUS OFF
        TYPE RASTER
        DUMP TRUE
        TILEINDEX 'testPressure_idx'
        PROJECTION
            "init=epsg:4326"
        END
        METADATA
            wcs_label 'metadata about test'
			ows_extent '-0.5625 -89.69761276245117 359.4375 89.69761276245117'
			wcs_resolution '1.125 -1.1212201595306397'
            ows_srs 'EPSG:4326'
            wcs_formats 'GTIFF_FLOAT'
            wcs_nativeformat 'NetCDF'
            wcs_bandcount '27'
            wcs_rangeset_axes 'bands'
            wcs_rangeset_label 'Pressure Levels'
            wcs_rangeset_name 'bands'
            wcs_timeposition '2001-01-31T18:00:00' 
            wcs_timeitem 'time'                    
        END
    END        
                
END
    

[nbarker@…]

Having investigated this bug, I am going to close it since (at least for NetCDF
files) the bug seems to be associated with my creation of temporal shapefiles.  

The suggested fix for DEMs worked fine, thanks.

Thanks for your help

[nbarker@…]

Fine for EPSG:4326, tried other EPSG codes and the server either hangs, or a
blank image is still returned.  Sorry about the red herring with the shape
files, we are creating map files from a database with a stylesheet and that was
unrelated error.

It seems to be the case with DEM geotiffs, and are netCDF geotiff, the files are
about 5.5mb and I can attach one if required

[nbarker@…]

built mapserver from source when fixing bugs and it works, so there was a
problem with the binary on our system.  thanks for the help.