[gdal-dev] WCS driver work

[Ari Jolma]

I've got very close to being able to get valid data (visual comparison 
in QGIS) from various server types and WCS versions.

I've documented the results here: 
https://trac.osgeo.org/gdal/wiki/WCS%2Binteroperability

It seems that I need eight option flags to cover all cases. Mostly the 
problems are with CRS that have inverted axis order. Also it seems to be 
a problem if the server or the standard does not support requesting 
directly tiles of specific size. It is especially a problem since GDAL 
fails the call if the size is not expected.

The only combination that I have not yet managed to get to work is 
GeoServer with version 1.1 and inverted axis order. I can get a decent 
response but the returned geotiff has slightly wrong size (59x38 instead 
of 60x38). The problematic call is below[1].

Also, I have/know only a few servers and I lack some combinations; I've 
also found a server with a combination that I've managed to test ok, but 
whose behavior I can't yet explain[2].

I'm writing documentation and test code but the latter will still take 
some time to be ready for the trunk.

The code is at https://github.com/ajolma/gdal/tree/trunk/gdal/frmts/wcs

I've also made one ticket regarding port code 
https://trac.osgeo.org/gdal/ticket/7141

Ari

[1] 
https://msp.smartsea.fmi.fi/geoserver/wcs?SERVICE=WCS&VERSION=1.1.0&REQUEST=GetCoverage&IDENTIFIER=smartsea%3Aeusm2016-EPSG2393&FORMAT=image%2Ftiff&BOUNDINGBOX=6620001.14539506,3199988.18514013,6670001.21326246,3279980.29051582,urn:ogc:def:crs:EPSG::2393&RangeSubset=contents&GridBaseCRS=urn:ogc:def:crs:EPSG::2393&GridCS=urn:ogc:def:cs:OGC:0.0:Grid2dSquareCS&GridType=urn:ogc:def:method:WCS:1.1:2dGridIn2dCrs&GridOrigin=6670001.21326246,3199988.18514013&GridOffsets=0,1333.20175626157,-1315.79125966838,0

[2] 
https://lists.osgeo.org/pipermail/mapserver-users/2017-November/080339.html