[Geoserver-users] WCS (1.1.1) reprojection parameters?

List:

Having "gifted" myself a copy of GeoServer for Christmas, I've been doing some WCS experimentation with the "nurc:Pk50095" coverage that comes in the sample dataset.

I successfully added the EPSG:4326 to the list of supported projections of this coverage. Thus, using the WCS 1.1.1 standard, I was able to request a subset of the image using EPSG:4326 coordinates:

http://localhost:8080/geoserver/wcs?
request=GetCoverage&
version=1.1.1&
identifier=nurc:Pk50095&
SERVICE=wcs&
FORMAT=image/geotiff&
BOUNDINGBOX=46.75,13.05,46.85,13.25,urn:ogc:def:crs:EPSG::4326

The resulting GeoTIFF is in the native projection of the coverage (EPSG:32633)--as expected.

My experiments ground to a halt when trying to figure out how to get my requested image back in the EPSG:4326 projection. Digging into the OGC documentation (OGC -7-067r5), in Table 28 I see that if I make a request for a projection other than a coverage's native projection, I see a number of promising parameters--

GridBaseCRS
GridType
GridCS

But no luck in figuring out the magic combination.

Any pointers on what I need to get my requested coverage back in the 4326 projection would be greatly appreciated.

Brian

--

Hi Brian,

After adding EPSG:4326 to the set of accepted projections and appending "&gridbasecrs=EPSG:4326" to the request you specified below what i get back appears to be a reprojected coverage.

I compared to result to a manual reprojection with gdalwarp and the two appear to line up (although the result from gdalwarp appears to be flattened somewhat).

Feel free to attach or post a screen shot of what you are getting back from the server.

-Justin

Brian Timoney wrote:

List:

Having "gifted" myself a copy of GeoServer for Christmas, I've been doing some WCS experimentation with the "nurc:Pk50095" coverage that comes in the sample dataset.

I successfully added the EPSG:4326 to the list of supported projections of this coverage. Thus, using the WCS 1.1.1 standard, I was able to request a subset of the image using EPSG:4326 coordinates:

http://localhost:8080/geoserver/wcs?
request=GetCoverage&
version=1.1.1&
identifier=nurc:Pk50095&
SERVICE=wcs&
FORMAT=image/geotiff&
BOUNDINGBOX=46.75,13.05,46.85,13.25,urn:ogc:def:crs:EPSG::4326

The resulting GeoTIFF is in the native projection of the coverage (EPSG:32633)--as expected.

My experiments ground to a halt when trying to figure out how to get my requested image back in the EPSG:4326 projection. Digging into the OGC documentation (OGC -7-067r5), in Table 28 I see that if I make a request for a projection other than a coverage's native projection, I see a number of promising parameters--

GridBaseCRS
GridType
GridCS

But no luck in figuring out the magic combination.

Any pointers on what I need to get my requested coverage back in the 4326 projection would be greatly appreciated.

Brian

--
Justin Deoliveira
OpenGeo - http://opengeo.org
Enterprise support for open source geospatial.

Justin:

You're suggestion worked like a charm--

http://localhost:8080/geoserver/wcs?request=GetCoverage&version=1.1.1&
identifier=nurc:Pk50095&
SERVICE=wcs&
FORMAT=image/geotiff&
BOUNDINGBOX=46.75,13.05,46.85,13.25,urn:ogc:def:crs:EPSG::4326&
gridbasecrs=EPSG:4326

It's always heartening when problems have simpler answers than you originally imagined.

Cheers,

Brian

Justin Deoliveira wrote:

Hi Brian,

After adding EPSG:4326 to the set of accepted projections and appending "&gridbasecrs=EPSG:4326" to the request you specified below what i get back appears to be a reprojected coverage.

I compared to result to a manual reprojection with gdalwarp and the two appear to line up (although the result from gdalwarp appears to be flattened somewhat).

Feel free to attach or post a screen shot of what you are getting back from the server.

-Justin

Brian Timoney wrote:

List:

Having "gifted" myself a copy of GeoServer for Christmas, I've been doing some WCS experimentation with the "nurc:Pk50095" coverage that comes in the sample dataset.

I successfully added the EPSG:4326 to the list of supported projections of this coverage. Thus, using the WCS 1.1.1 standard, I was able to request a subset of the image using EPSG:4326 coordinates:

http://localhost:8080/geoserver/wcs?
request=GetCoverage&
version=1.1.1&
identifier=nurc:Pk50095&
SERVICE=wcs&
FORMAT=image/geotiff&
BOUNDINGBOX=46.75,13.05,46.85,13.25,urn:ogc:def:crs:EPSG::4326

The resulting GeoTIFF is in the native projection of the coverage (EPSG:32633)--as expected.

My experiments ground to a halt when trying to figure out how to get my requested image back in the EPSG:4326 projection. Digging into the OGC documentation (OGC -7-067r5), in Table 28 I see that if I make a request for a projection other than a coverage's native projection, I see a number of promising parameters--

GridBaseCRS
GridType
GridCS

But no luck in figuring out the magic combination.

Any pointers on what I need to get my requested coverage back in the 4326 projection would be greatly appreciated.

Brian

--

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518 17th Street Suite 1000
Denver, CO 80202

Ph: (303) 929-3722
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