[mapserver-dev] problems serving DTED data via WCS

[Frank Warmerdam]

Jim,

The GDAL DTED driver is rather peculiar and only works for certain
very specific products.  This is briefly addressed in the document at:

  http://www.gdal.org/frmt_dted.html

But in brief, you should not depend on this driver for producing
files with arbitrary bounds, resolution and coordinate system.

Best regards,
Frank

On Tue, Aug 23, 2011 at 12:58 PM, Jim Hammack <hammack at gotslack.org> wrote:
> I am trying to serve DTED data in its native format using WCS with mapserver
> 6.0.0 on Slackware 13.1.   If I serve the data as a 16-bit GeoTIFF or do a
> WCS 2.0.0 GetCoverage with a PNG output, the images look good.  But when I
> serve the same data using the GDAL/DTED driver the .dt1 file contains only 0
> values for the data when using GetCoverage.  Interestingly, shp2img gives me
> a file with nothing but 21074 (0x5252) for the data values.  In both cases
> the output of gdalinfo looks okay.
>
> So it seems like mapserver is finding the data okay, but gdal (1.8.0) is not
> writing the dt1 file properly.
>
> Am I missing something in the WCS configuration or is gdal confused?
>
>                                                                Thanks,
>                                                                    Jim
>
>
> ------------------------
> # this works
> OUTPUTFORMAT
>  NAME "GEOTIFFINT16"
>  DRIVER "GDAL/GTiff"
>  MIMETYPE "image/tiff"
>  IMAGEMODE "INT16"
>  EXTENSION "tif"
> END
>
> shp2img -m dted1.map -i PNG -l "elevation" -o fred.dt1 -e -90.0 30.0 -89.0
> 31.0  # works
>
> http://localhost/cgi-bin/mapserv?map=/mapserver/dted1.map&SERVICE=WCS&VERSION=2.0.0&REQUEST=GetCoverage&coverageid=elevation&format=png&subset=lon_axis,http://www.opengis.net/def/crs/EPSG/0/4326(-90.0,-89.0)&subset=lat_axis,http://www.opengis.net/def/crs/EPSG/0/4326(30.0,31.0)
>
> ---------------------------
> # this does not
> OUTPUTFORMAT
>    NAME "DTED"
>    DRIVER "GDAL/DTED"
>   IMAGEMODE "INT16"
>    EXTENSION "dt1"
> END
>
> shp2img -m dted1.map -i DTED -l "elevation" -o fred.dt1 -e -90.0 30.0 -89.0
> 31.0  # contains 0x5252 values only
>
> http://localhost/cgi-bin/mapserv?map=/mapserver/dted1.map&SERVICE=WCS&VERSION=2.0.0&REQUEST=GetCoverage&coverageid=elevation&format=DTED&subset=lon_axis,http://www.opengis.net/def/crs/EPSG/0/4326(-90.0,-89.0)&subset=lat_axis,http://www.opengis.net/def/crs/EPSG/0/4326(30.0,31.0)
>  # contains zero values only
>
> ---------------------------
>
> mojo:/mapserver> gdalinfo fred.dt1
> Driver: DTED/DTED Elevation Raster
> Files: fred.dt1
>       fred.dt1.aux.xml
> Size is 1201, 1201
> Coordinate System is:
> GEOGCS["WGS 84",
>    DATUM["WGS_1984",
>        SPHEROID["WGS 84",6378137,298.257223563]],
>    PRIMEM["Greenwich",0],
>    UNIT["degree",0.0174532925199433],
>    AUTHORITY["EPSG","4326"]]
> Origin = (-90.000416666666666,31.000416666666666)
> Pixel Size = (0.000833333333333,-0.000833333333333)
> Metadata:
>  DTED_VerticalAccuracy_UHL=NA
>  DTED_VerticalAccuracy_ACC=NA
>  DTED_SecurityCode_UHL=U
>  DTED_SecurityCode_DSI=U
>  DTED_UniqueRef_UHL=
>  DTED_UniqueRef_DSI=000000000000000
>  DTED_DataEdition=01
>  DTED_MatchMergeVersion=A
>  DTED_MaintenanceDate=0000
>  DTED_MatchMergeDate=0000
>  DTED_MaintenanceDescription=0000
>  DTED_Producer=
>  DTED_VerticalDatum=MSL
>  DTED_HorizontalDatum=WGS84
>  DTED_DigitizingSystem=
>  DTED_CompilationDate=
>  DTED_HorizontalAccuracy=NA
>  DTED_RelHorizontalAccuracy=NA
>  DTED_RelVerticalAccuracy=NA
>  DTED_OriginLatitude=0300000N
>  DTED_OriginLongitude=0900000W
>  DTED_NimaDesignator=DTED1
>  AREA_OR_POINT=Point
>  TIFFTAG_XRESOLUTION=72.000000
>  TIFFTAG_YRESOLUTION=72.000000
>  TIFFTAG_RESOLUTIONUNIT=2
> Corner Coordinates:
> Upper Left  ( -90.0004167,  31.0004167) ( 90d 0' 1.50"W, 31d 0' 1.50"N)
> Lower Left  ( -90.0004167,  29.9995833) ( 90d 0' 1.50"W, 29d59'58.50"N)
> Upper Right ( -88.9995833,  31.0004167) ( 88d59'58.50"W, 31d 0' 1.50"N)
> Lower Right ( -88.9995833,  29.9995833) ( 88d59'58.50"W, 29d59'58.50"N)
> Center      ( -89.5000000,  30.5000000) ( 89d30' 0.00"W, 30d30' 0.00"N)
> Band 1 Block=1x1201 Type=Int16, ColorInterp=Undefined
>  NoData Value=-32767
>  Unit Type: m
>
>
>
>
>
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>



-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Software Developer