On jeudi 17 mai 2018 11:33:40 CEST Bang Pham Huu wrote: > 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?
Hi, You can use gdal.AutoCreateWarpedVRT() which will create a in-memory warped VRT without doing the actual warping. http://gdal.org/java/org/gdal/gdal/gdal.html#AutoCreateWarpedVRT-org.gdal.gdal.Dataset- and query the dimensions of the returned Dataset Even -- Spatialys - Geospatial professional services http://www.spatialys.com
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