[gdal-dev] WMS Psuedo GetMap Request and image resolution

[Kyle Shannon]

Hello,
I am trying to use WMS to obtain some elevation data from the USGS seamless
server.  I use the following syntax:

gdalinfo "WMS:
> http://imselev.cr.usgs.gov:80/wmsconnector/com.esri.wms.Esrimap/USGS_EDC_Elev_NED?REQUEST=GetMap&VERSION=1.1.0&LAYERS=NED.CONUS_NED&SRS=EPSG:4326&FORMAT=image/tiff&BBOX=-113.0,44.5,-112.75,44.75&WIDTH=600&HEIGHT=600
> "
>

The output is:

WMS: Opening WMS :
> <GDAL_WMS>
>   <Service name="WMS">
>     <Version>1.1.0</Version>
>     <ServerUrl>
> http://imselev.cr.usgs.gov:80/wmsconnector/com.esri.wms.Esrimap/USGS_EDC_Elev_NED
> ?</ServerUrl>
>     <Layers>NED%2ECONUS_NED</Layers>
>     <SRS>EPSG:4326</SRS>
>     <ImageFormat>image/tiff</ImageFormat>
>     <Transparent>FALSE</Transparent>
>   </Service>
>   <DataWindow>
>     <UpperLeftX>-113.0</UpperLeftX>
>     <UpperLeftY>44.75</UpperLeftY>
>     <LowerRightX>-112.75</LowerRightX>
>     <LowerRightY>44.5</LowerRightY>
>     <SizeX>1073741824</SizeX>
>     <SizeY>1073741824</SizeY>
>   </DataWindow>
>   <BandsCount>3</BandsCount>
>   <BlockSizeX>1024</BlockSizeX>
>   <BlockSizeY>1024</BlockSizeY>
>   <OverviewCount>20</OverviewCount>
> </GDAL_WMS>
>
> GDAL: GDALOpen(WMS:
> http://imselev.cr.usgs.gov:80/wmsconnector/com.esri.wms.Esrimap/USGS_EDC_Elev_NED?REQUEST=GetMap&VERSION=1.1.0&LAYERS=NED.CONUS_NED&SRS=EPSG:4326&FORMAT=image/tiff&BBOX=-113.0,44.5,-112.75,44.75&WIDTH=600&HEIGHT=600,
> this=0xf9f7e0) succeeds as WMS.
> Driver: WMS/OGC Web Map Service
> Files: none associated
> Size is 1073741824, 1073741824
> Coordinate System is:
> GEOGCS["WGS 84",
>     DATUM["WGS_1984",
>         SPHEROID["WGS 84",6378137,298.257223563,
>             AUTHORITY["EPSG","7030"]],
>         AUTHORITY["EPSG","6326"]],
>     PRIMEM["Greenwich",0,
>         AUTHORITY["EPSG","8901"]],
>     UNIT["degree",0.0174532925199433,
>         AUTHORITY["EPSG","9122"]],
>     AUTHORITY["EPSG","4326"]]
> Origin = (-113.000000000000000,44.750000000000000)
> Pixel Size = (0.000000000232831,-0.000000000232831)
> Image Structure Metadata:
>   INTERLEAVE=PIXEL
> OGRCT: Source: +proj=longlat +datum=WGS84 +no_defs
> OGRCT: Target: +proj=longlat +datum=WGS84 +no_defs
> Corner Coordinates:
> Upper Left  (-113.0000000,  44.7500000) (113d 0' 0.00"W, 44d45' 0.00"N)
> Lower Left  (-113.0000000,  44.5000000) (113d 0' 0.00"W, 44d30' 0.00"N)
> Upper Right (-112.7500000,  44.7500000) (112d45' 0.00"W, 44d45' 0.00"N)
> Lower Right (-112.7500000,  44.5000000) (112d45' 0.00"W, 44d30' 0.00"N)
> Center      (-112.8750000,  44.6250000) (112d52'30.00"W, 44d37'30.00"N)
> Band 1 Block=1024x1024 Type=Byte, ColorInterp=Red
>   Overviews: 536870912x536870912, 268435456x268435456, 134217728x134217728,
> 67108864x67108864, 33554432x33554432, 16777216x16777216, 8388608x8388608,
> 4194304x4194304, 2097152x2097152, 1048576x1048576, 524288x524288,
> 262144x262144, 131072x131072, 65536x65536, 32768x32768, 16384x16384,
> 8192x8192, 4096x4096, 2048x2048, 1024x1024
> Band 2 Block=1024x1024 Type=Byte, ColorInterp=Green
>   Overviews: 536870912x536870912, 268435456x268435456, 134217728x134217728,
> 67108864x67108864, 33554432x33554432, 16777216x16777216, 8388608x8388608,
> 4194304x4194304, 2097152x2097152, 1048576x1048576, 524288x524288,
> 262144x262144, 131072x131072, 65536x65536, 32768x32768, 16384x16384,
> 8192x8192, 4096x4096, 2048x2048, 1024x1024
> Band 3 Block=1024x1024 Type=Byte, ColorInterp=Blue
>   Overviews: 536870912x536870912, 268435456x268435456, 134217728x134217728,
> 67108864x67108864, 33554432x33554432, 16777216x16777216, 8388608x8388608,
> 4194304x4194304, 2097152x2097152, 1048576x1048576, 524288x524288,
> 262144x262144, 131072x131072, 65536x65536, 32768x32768, 16384x16384,
> 8192x8192, 4096x4096, 2048x2048, 1024x1024
> GDAL: GDALClose(WMS:
> http://imselev.cr.usgs.gov:80/wmsconnector/com.esri.wms.Esrimap/USGS_EDC_Elev_NED?REQUEST=GetMap&VERSION=1.1.0&LAYERS=NED.CONUS_NED&SRS=EPSG:4326&FORMAT=image/tiff&BBOX=-113.0,44.5,-112.75,44.75&WIDTH=600&HEIGHT=600,
> this=0xf9f7e0)
> GDAL: In GDALDestroy - unloading GDAL shared library.
>

Fair warning/apology, this is the first time I have used WMS.  But I would
think that my image would be 600x600 as specified in the request, and have a
much larger pixel resolution.  Am I doing something wrong?  Thanks.

kss

/**
 *
 * Kyle Shannon
 * ksshannon at gmail.com
 *
 */
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