On mardi 25 juin 2019 19:57:11 CEST LEGGE Melvin wrote: > Hi > > I am a relative newbie to GIS programming so forgive me if I use the wrong > terminology or don't state my problem in the most efficient GIS terms. > Anyway, I have inherited a project written by an actual GIS person who is > no longer with the company. > > The DTED data consists of 4 GDalDatasets with actual DTED elevation data not > reaching the boundaries of GDalDatasets - i.e., GDalDatasets are bigger > than the actual DTED data. Our program reads the elevation data along a > bearing line from a given point to some requested distance, at regular > intervals, by repeatedly calling GDALRasterBand->RasterIO for a specified > distance. What I am seeing is that elevation values of 0 are returned for > points between the end of the DTED data and the end of the tile. > > Is there any way I can distinguish between the situation above and an actual > elevation of 0?
No this looks like a "bug" in the data production itself. You could probably add your own custom logic to detect that situation and fix those 0 on the edges of the product to nodata (nearblack might be of help for this) Even -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
