Dear Geotools developers, we still have problems when reprojecting raster data, which we basically already described in
http://www.nabble.com/Raster-file-reprojection-problems-tf3180801.html#a8826611 Unfortunately, we have not yet received any feedback on this. The current behaviour of our application is as follows: We have a world map containing a layer with geometries taken from a shapefile, a layer with lat/lon lines, and a layer containing a grid coverage (raster data from a jpg file (an underlying NASA Bluemarble image)). We now use the StreamingRenderer for this, which basically does the job. We now reproject from a rectangular CRS into a target CRS using an AzimuthalEquidistant projection. We implemented this as a new projection, following the Geotools tutorial "How to add new projections". Basically, everything works fine for the shapefile layer, but not for the raster data layer. Parts of the image data get lost in a way which we hardly understand. It is somehow dependent on the view settings (latitude/longitude of origin, and view angle). We can reproduce the behaviour, but we cannot really see a system in it when we change the view settings. We now tried two more things: 1) We tried all the same, but changed the projection from the AzimuthalEquidistant to a PolarStereographic, which was already available in the Geotools collection of projections. We found a very similar errorneous behaviour, so the problems do not seem to be related to the projection part. 2) This was confirmed by a further test: We set up a "grid layer" consisting of points (com.vividsolutions.jts.geom.Point ) located on a lat/lon grid from [-180, 180], [-90,90] with 1 deg. resolution. This data is reprojected correctly. As an illustration, we attached the following screenshots: - image_shape_grid_rect.PNG : all data correctly displayed in an EquidistantRectangular projection - image_shape_grid_azim_*.PNG: raster data incorrectly displayed in AzimuthalEquidistant projection - image_shape_grid_stereo_45.PNG: raster data incorrectly displayed in PolarStereographic projection - *test*.png: same images as before, but with the test "grid layer", displayed as magenta-coloured circles We would really appreciate if anyone of you could find a bit of time to think about this problem, since this is really a blocker for our project. Maybe it is something which you already know about? Our company has some experience and knowledge in processing image data, so perhaps we could further work on this and provide a solution once we get some hints where to search what causes the problems. A candidate might be the GridCoverageRenderer where obviously several steps of data manipulation are carried out? Thanks in advance for any help! Olaf Rectangular projection: http://www.nabble.com/file/7446/image_shape_grid_rect.PNG http://www.nabble.com/file/7451/image_shape_grid_test_rect.PNG Azimuthal-equidistant projection: http://www.nabble.com/file/7443/image_shape_grid_azim_1.PNG http://www.nabble.com/file/7444/image_shape_grid_azim_2.PNG http://www.nabble.com/file/7445/image_shape_grid_azim_45.PNG http://www.nabble.com/file/7448/image_shape_grid_test_azim_1.PNG http://www.nabble.com/file/7449/image_shape_grid_test_azim_2.PNG http://www.nabble.com/file/7450/image_shape_grid_test_azim_45.PNG Polar-stereographic projection: http://www.nabble.com/file/7447/image_shape_grid_stereo_45.PNG http://www.nabble.com/file/7452/image_shape_grid_test_stereo_45.PNG -- View this message in context: http://www.nabble.com/Still-problems-with-reprojecting-raster-data-tf3472146.html#a9689563 Sent from the geotools-devel mailing list archive at Nabble.com. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Geotools-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-devel
