[gdal-dev] [Geoserver-devel] GML lat-lon coverages and interoperability

[jratike80]

Peter Baumann wrote
> Hi all,
> 
> why not simply check against the compliance tests of WCS 2 and maybe a
> reference
> implementation? Might be the easiest for answering all such questions.
> 
> cheers,
> 
> Peter

Hi,

I could not find exact match for raster image (GeoTIFF) case from
http://cite.opengeospatial.org/teamengine/about/wcs/2.0.1/site/ or
http://schemas.opengis.net/wcs/2.0/examples/.


When it comes to reference implementation, by following the link
http://standards.rasdaman.org/ to the WCS endpoint demo using service
http://ows.rasdaman.org/rasdaman/ows and then to coverage BlueMarbleCov I
can read that DescribeCoverage contains this:

    <coverageFunction>
      <GridFunction>
        <sequenceRule axisOrder="+2 +1">Linear</sequenceRule>
        <startPoint>0 0</startPoint>
      </GridFunction>
    </coverageFunction>
    <gmlcov:metadata/>
    <domainSet>
      <RectifiedGrid dimension="2" gml:id="BlueMarbleCov-grid">
        <limits>
          <GridEnvelope>
            <low>0 0</low>
            <high>17999 8999</high>
          </GridEnvelope>
        </limits>
        <axisLabels>Lat Long</axisLabels>
        <origin>
          <Point gml:id="BlueMarbleCov-origin"
srsName="http://ows.rasdaman.org/def/crs/EPSG/0/4326">
            <pos>89.99 -179.99</pos>
          </Point>
        </origin>
        <offsetVector
srsName="http://ows.rasdaman.org/def/crs/EPSG/0/4326">-0.02 0</offsetVector>
        <offsetVector
srsName="http://ows.rasdaman.org/def/crs/EPSG/0/4326">0 0.02</offsetVector>
      </RectifiedGrid>

So both the Rasdaman demo and Geoserver are using gridFunction axisOrder +2
+1 with EPSG:4326. However, on April 4th you wrote on this mailing list:

"So it is not necessary to use GridFunctions for this purpose. My personal
opinion is that such mechanisms are not optimal for fiddling with coordinate
positions as they make it unnecessarily
difficult to determine the final pixel position."

I am not yet sure what is the conclusion.

-Jukka Rahkonen-






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