I don't understand the problem :)

Maybe it's because I ran gdalinfo on the WCS first.

For the gdallocationinfo I get

gdallocationinfo "WCS:https://elevation.nationalmap.gov:443/arcgis/services/3DEPElevation/ImageServer/WCSServer?version=2.0.1&coverage=DEP3Elevation"; -wgs84 -122.086 42.948
Report:
  Location: (6446955P,13504941L)
  Band 1:
    Value: 1882.00549316406

Ari

Rahkonen Jukka (MML) kirjoitti 21.10.2021 klo 21.56:

Hi,

I wonder if the problem is in the multipart response that the nationalmap.gov server is sending. The result is not too big tiff (1023x511 pixels as revealed by <gml:high>1023 511</gml:high>) but perhaps GDAL does not know how to extract it from the multipart envelope. I do not know either. I thought that multipart was only an issue with WCS 1.1.x but obviously it can be used also with WCS 2.0. I do understand how brilliant idea multipart response is in theory but unfortunately it is a pain for the users.

This is the beginning of the response:


--wcs

Content-Type: text/xml

Content-ID: GML-Part

  <gml:boundedBy>

    <gml:Envelope srsName=http://www.opengis.net/def/crs/EPSG/0/3857 <http://www.opengis.net/def/crs/EPSG/0/3857> axisLabels="x y" uomLabels=" " srsDimension="2">

      <gml:lowerCorner>3005564.702644 10446506.055425</gml:lowerCorner>

      <gml:upperCorner>3006588.702633 10447018.055420</gml:upperCorner>

    </gml:Envelope>

  </gml:boundedBy>

  <gml:domainSet>

    <gml:RectifiedGrid dimension="2" gml:id="grid_Coverage1">

      <gml:limits>

        <gml:GridEnvelope>

          <gml:low>0 0</gml:low>

          <gml:high>1023 511</gml:high>

        </gml:GridEnvelope>

      </gml:limits>

<gml:axisLabels>band_1</gml:axisLabels>

      <gml:origin>

        <gml:Point gml:id="grid_origin_Coverage1" srsName=http://www.opengis.net/def/crs/EPSG/0/3857 <http://www.opengis.net/def/crs/EPSG/0/3857>>

          <gml:pos>3005564.702644 10446506.055425</gml:pos>

        </gml:Point>

      </gml:origin>

      <gml:offsetVector srsName=http://www.opengis.net/def/crs/EPSG/0/3857 <http://www.opengis.net/def/crs/EPSG/0/3857>>XOFFSET1.000000XOFFSET 0 </gml:offsetVector>

      <gml:offsetVector srsName=http://www.opengis.net/def/crs/EPSG/0/3857 <http://www.opengis.net/def/crs/EPSG/0/3857>>0 YOFFSET1.000000YOFFSET </gml:offsetVector>

    </gml:RectifiedGrid>

  </gml:domainSet>

  <gml:rangeSet>

    <gml:File>

      <gml:rangeParameters xlink:href=cid:Coverage1.tif <cid:Coverage1.tif> xlink:role=http://www.opengis.net/spec/WCS_coverageencoding_geotiff/1.0/ <http://www.opengis.net/spec/WCS_coverageencoding_geotiff/1.0/> xlink:arcrole="fileReference"/>

      <gml:fileReference>cid:Coverage1.tif</gml:fileReference <cid:Coverage1.tif%3c/gml:fileReference>>

      <gml:fileStructure/>

<gml:mimeType>image/tiff</gml:mimeType>

    </gml:File>

  </gml:rangeSet>

  <gmlcov:rangeType>

    <swe:DataRecord>

      <swe:field name="band_1">

        <swe:Quantity>

<swe:description>band_1</swe:description>

          <swe:uom code="unknown"/>

          <swe:constraint>

            <swe:AllowedValues>

              <swe:interval>3.4E-38 3.4E+38</swe:interval>

            </swe:AllowedValues>

          </swe:constraint>

        </swe:Quantity>

      </swe:field>

    </swe:DataRecord>

  </gmlcov:rangeType>

</gmlcov:RectifiedGridCoverage>

--wcs

Content-Type: image/tiff

Content-Description: coverage data

Content-Transfer-Encoding: binary

Content-ID: 1.tif

…

-Jukka Rahkonen-

*Lähettäjä:* gdal-dev <[email protected]> *Puolesta *Carl Godkin
*Lähetetty:* torstai 21. lokakuuta 2021 18.47
*Vastaanottaja:* [email protected]
*Aihe:* [gdal-dev] gdallocationinfo + WCS question...

Hi,

I am trying to use gdallocationinfo to query point locations from a WCS server and not having any luck. I don't see anything in the docs that says this is unsupported but I can't make it work.

First of all, is there a better way to get an elevation from a given lat,lon using WCS?

Here's an example query using the USGS National Map server:

gdallocationinfo "WCS:https://elevation.nationalmap.gov:443/arcgis/services/3DEPElevation/ImageServer/WCSServer?version=2.0.1&coverage=DEP3Elevation <https://elevation.nationalmap.gov:443/arcgis/services/3DEPElevation/ImageServer/WCSServer?version=2.0.1&coverage=DEP3Elevation>" -wgs84 -122.086 42.948 --debug ON

This is a point in the middle of Crater Lake which I picked since it's flat and I know what to expect.

Anyway, looking at the debug output it appears that the program is querying for a GeoTIFF of a VERY large area and that's failing.

I actually want to do this with my own WCS server but thought it might be mis-configured somehow so I tried the USGS server.  With my own server, gdallocationinfo seems to be requesting a strange shape from the server (as I can see through the debug output).

Thanks for any help,

carl


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