[gdal-dev] from projection coordinates to pixel coords
Hi, How can we transform from projection coordinates to pixel coords with gdal c++ ? regards -- Ahmet Temiz Jeoloji Müh. Afet ve Acil Durum Yönetimi Başkanlığı Bilgi İşlem Dairesi Başkanlığı-CBS Grubu Ahmet Temiz Geological Eng. Information Systems - GIS Group Disaster and Emergency Management of Presidency ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] from projection coordinates to pixel coords
Hi Ahmet, I would suggest for your to look into the raster tutorial page and search for all the occurrences of "adfGeoTransform" and read the comments and code related to that. https://gdal.org/tutorials/raster_api_tut.html Another good source code to take a look is the gdal_translate_lib.cpp code where you can search for the same variable name and see how the parameters "-srcwin" and "-srcproj" are handled on that. That is what you need, right? https://github.com/OSGeo/gdal/blob/master/gdal/apps/gdal_translate_lib.cpp Of course you can also check the GDAL API documentation: https://gdal.org/api/gdaldataset_cpp.html Best regards, Ivan From: gdal-dev on behalf of Ahmet Temiz Sent: Wednesday, July 31, 2019 6:56 AM To: gdal-dev Subject: [gdal-dev] from projection coordinates to pixel coords Hi, How can we transform from projection coordinates to pixel coords with gdal c++ ? regards -- Ahmet Temiz Jeoloji Müh. Afet ve Acil Durum Yönetimi Başkanlığı Bilgi İşlem Dairesi Başkanlığı-CBS Grubu Ahmet Temiz Geological Eng. Information Systems - GIS Group Disaster and Emergency Management of Presidency ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] OSRSetPROJSearchPaths in multithreaded application
I apologize for resurrecting this thread, but we are running into the same problem, even after updating the the head of the "release/3.0" branch which contains Even's fix. Previously, we would set PROJ_LIB as an environment variable but after upgrading to 3.x/6.x we now receive thousands of "proj.db not found" errors. After checking out the above branch, I removed the environment variable and call OSRSetPROJSearchPaths before calling GDALAllRegister at the start of my main thread but the problem remains. What's odd is that it only happens if we use a lot of threads, which makes me think there may still be a race condition somewhere in GDAL? If I change my code to be single-threaded, the problem goes away completely. And advice you could offer would be much appreciated. Thanks! On Wed, Jul 17, 2019 at 1:27 PM Dirk Vanden Boer wrote: > > > Op wo 17 jul. 2019 om 17:57 schreef Even Rouault < > even.roua...@spatialys.com> > >> > I did some more investigation, and it seems like the threading is >> > indeed not the issue. >> > The issue seems to be that the geotiff library also creates proj >> > contexts and these contexts do not have >> > the search paths that are passed to the OSRGetProjTLSContext call. >> >> Should be fixed per >> >> https://github.com/OSGeo/gdal/commit/48793b5613cf1bf789125516ba845947dc63098f >> in master >> and >> >> https://github.com/OSGeo/gdal/commit/ffb0ad0c862cf4ef5d6907d1d83cc76fcf8c305b >> in 3.0 branch >> > > Great, thanks for the quick response and fixes! > >> >> ___ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/gdal-dev ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] NetCDF driver getting wrong values if compared to HDF5
On mardi 30 juillet 2019 21:48:45 CEST Ivan Lucena wrote: > Unsupported netCDF datatype (7), treat as Float32. Given that #define NC_UBYTE7 /**< unsigned 1 byte int */ and https://github.com/OSGeo/gdal/blob/master/gdal/frmts/netcdf/netcdfdataset.cpp#L357 it seems you would have a GDAL build against a netCDF build without NC4 support. That said, even with that, I would have expected the ubyte to float32 conversion to be lossless. but according to https://www.unidata.ucar.edu/software/netcdf/docs/group__variables.html#ga0ab808702d73b7f52be14b1e54473902 """ The nc_get_vara() function will read a variable of any type, including user defined type. For this function, the type of the data in memory must match the type of the variable - no data conversion is done. """ So you could get pretty much garbage. Solution: build GDAL against a netCDF build that has NC4 support Even -- Spatialys - Geospatial professional services http://www.spatialys.com ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
[gdal-dev] (no subject)
Hi, I need example c++ code for raster masking and clipping. Do you have any? Regards -- Ahmet Temiz Jeoloji Müh. Afet ve Acil Durum Yönetimi Başkanlığı Bilgi İşlem Dairesi Başkanlığı-CBS Grubu Ahmet Temiz Geological Eng. Information Systems - GIS Group Disaster and Emergency Management of Presidency ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
