You could use osr's CoordinateTransformation to evaluate the new location of the four corners in the destination spatial reference: http://gdal.org/python/osgeo.osr.CoordinateTransformation-class.html
From there a min/max on the four coordinates will give you the extent of the new image space. If the input and output CRS are very dissimilar you might want to evaluate a regular grid instead to get a more representative extent. Benjamin Deschamps Physical Sciences Specialist Canadian Ice Service, Meteorological Service of Canada Environment and Climate Change Canada / Government of Canada [email protected] / Tel: 613-943-4293 Spécialiste des sciences physiques Service Canadien des Glaces, Service Météorologique du Canada, Environnement et Changement climatique Canada / Gouvernement du Canada [email protected] / Tél. : 613-943-4293 -----Original Message----- From: Bang Pham Huu [mailto:[email protected]] Sent: May 17, 2018 5:34 AM To: [email protected] Subject: [gdal-dev] How to estimate the width/height size of output image in a target CRS without running gdalwarp? Hi, I have a hard problem to find the width/height of a 2D GeoTiff file which is reprojected from a source CRS (e.g: EPSG:4326) to target CRS (e.g: EPSG:3857) without running gdalwarp. Because, the file could be large (GBs) and I don't need the projected output file, just need the width/height of it. What could be done with gdalwarp is: gdalwarp -s_srs EPSG:4326 -t_srs EPSG:3857 full.tif full_3857.tif gdalinfo full_3857.tif Size is 879, 811 (width/height). I've searched a lot and what seems to be good without doing the real projection is this gdal function: GDALSuggestedWarpOutput2 https://github.com/OSGeo/gdal/blob/106c8288e7a05f4efc1a588c5a3b2da7ec52d915/gdal/alg/gdaltransformer.cpp#L354. However, it doesn't help because my application developed in Java and it uses gdal-java (GDAL JNI) https://search.maven.org/#artifactdetails%7Corg.gdal%7Cgdal%7C1.11.1%7Cpom as library. Unfortunately, I cannot find this GDALSuggestedWarpOutput2() from gdal-java http://gdal.org/java/overview-summary.html then cannot invoke this C++ function from my application to test. Can anyone please give me a hint to solve this problem? Thanks, _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
