Hi Zack, Your function sounds great. We've tried to implement something similar last summer but couldn't get it to work properly. I have no authority to say if this should be implemented in GDAL or not, but you've got my vote ;)
Thanks, Paul *Paul Meems * Release manager, configuration manager and forum moderator of MapWindow GIS. www.mapwindow.org Owner of MapWindow.nl - Support for Dutch speaking users. www.mapwindow.nl 2014/1/9 Zachary L. Stauber <zach...@stauber.org> > Dear developers, > I would like to contribute some code to the project. I have a > utility I call gdal_clip I wrote wrote in C++, which I used to compile > against the FWTools gdal .lib file and later Mr. Szekeres .lib files, which > will "clip" an image. It uses an input image and an input polygon > shapefile, and where the polygons in the shapefile overlap the image, it > will fill them in with a chosen color (defaults to black). It will NOT > resize the output image in any way. > This was useful for me to black out, or white out areas of tiles in > orthophoto projects that were outside the project boundary (outside of > control network and therefore of low accuracy). I am out of the > photogrammetry business, but I have photogrammetry colleagues who wish for > me to recompile this every time there is a new set of builds on > gisinternals.com/sdk, so it may be useful to build it into GDAL's code. > It is pretty optimized, not doing a pixel-in-polygon check for EVERY > pixel, but breaking the image into tiles and then breaking those tiles into > quarters only if they intersect the polygons, and so forth down to > individual pixels. It works correctly with doughnut polygons and rotated > images. I probably need to pretty up the code in some way friendly to > Doxygen, but otherwise it is ready to go. > In the future I'd like to generalize the code to deal with polygons > from any vector data source that OGR reads, and optionally resize an image > to cut it down if large parts are clipped. It would also be nice to make > it smart enough to reproject the input polygons to the image's coordinate > reference system if they are not the same. I also think right now it only > reads in and outputs TIFF images. But again, I think it is useful right > now. Please let me know if you all think this would be useful or would > like the code to see. > It is all MIT license right now, but could be changed to GDAL's > standard license if necessary. > > -Zack Stauber > Albuquerque, New Mexico > United States > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev >
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