[Geoserver-devel] On the fly raster reprojection issue

GeoServer GeoServer Developer
,
1

Hi list,

I’m trying to display a raster with global extent in conic and polar projection.
The rasters native projection is EPSG:4326.
Here is an example of gtopo raster in its native projection:
http://basemap.ru/gstest/rst/wms?service=WMS&version=1.1.0&request=GetMap&layers=rst:gtopo_hsh&styles=&bbox=-180.0,-84.00095511048,180.00281055284,83.62424716066&width=708&height=330&srs=EPSG:4326&format=application/openlayers

When I display it in example in EPSG:3411 I get a huge artifact at the pole and an artifact at a dateline meridian, which looks different depending on a zoom level:
http://basemap.ru/gstest/rst/wms?service=WMS&version=1.1.0&request=GetMap&layers=rst:gtopo_hsh&styles=&bbox=-3.067681275187825E8,-3.067681264858888E8,3.0676812855167615E8,3.0676812545299506E8&width=512&height=511&srs=EPSG:3411&format=application/openlayers

This happens with all rasters I try to reproject on the fly.
I guess this is a bug. Can it be fixed somehow?

I know I have a workaround by pre-projecting rasters in some desktop gis or gdal before publishing on geoserver, but I need on-the-fly reprojection, because my client app has an instrument to change map projection.
I’ve got lots of raster layers generated every day, so preprojecting them all to 4 of available projections (which means number of layers on gs *4) and then rewriting the app code to modify getmap request for a different layer depending on chosen projection is a very bad option.

Nick

2

On Wed, Apr 10, 2013 at 1:31 PM, Gis Mage <gismage@anonymised.com> wrote:

Hi list,

I'm trying to display a raster with global extent in conic and polar
projection.
The rasters native projection is EPSG:4326.
Here is an example of gtopo raster in its native projection:

http://basemap.ru/gstest/rst/wms?service=WMS&version=1.1.0&request=GetMap&layers=rst:gtopo_hsh&styles=&bbox=-180.0,-84.00095511048,180.00281055284,83.62424716066&width=708&height=330&srs=EPSG:4326&format=application/openlayers

When I display it in example in EPSG:3411 I get a huge artifact at the
pole and an artifact at a dateline meridian, which looks different
depending on a zoom level:

http://basemap.ru/gstest/rst/wms?service=WMS&version=1.1.0&request=GetMap&layers=rst:gtopo_hsh&styles=&bbox=-3.067681275187825E8,-3.067681264858888E8,3.0676812855167615E8,3.0676812545299506E8&width=512&height=511&srs=EPSG:3411&format=application/openlayers

This happens with all rasters I try to reproject on the fly.
I guess this is a bug. Can it be fixed somehow?

The issue has been known for a while, to fix it several changes in GeoTools
are needed, that's why it has not been fixed so far (it's days of work).
We're basically waiting for funding to tackle this one.

Cheers
Andrea

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