Carmelo, In the code n30.dt0 is some raster image file. Replace it with your image path. The array named 'data' was renamed to pippo. Correct that.
Refer to GDALDataset::GetGeoTransform() method at http://www.gdal.org/classGDALDataset.html Use GDALDataset::RasterIO() or GDALRasterIO while treating the pointer to a double variable as the buffer (pData in the function definition). On Tue, Aug 31, 2010 at 8:41 PM, Carmelo Terrasi <[email protected]>wrote: > Hello everybody, > first of all my apologies cause I'm a newbie with this stuff... > > I'm trying to build a function able to extract altitude from latitude and > longitude as parameters. > Something like that: *double MyElevation(double lat, double lon)* > * > * > I'm using Dted level 0 to get the elevation (I've already read this post: > http://www.osgeo.org/pipermail/gdal-dev/2010-February/023457.html ) > But I got lost... :( > > *GDALAllRegister(); > * > *pointerToDataSet=(GDALDataset*) GDALOpen("n30.dt0", GA_ReadOnly);* > * * > *double data[6];* > *double longitude, latitude;* > * > * > *pointerToDataSet->GetGeoTransform(data);* > * > * > *longitude=???;* > *latitude=???;* > * * > *double x = (longitude - pippo[0]) / pippo[1];* > *double y = (latitude - pippo[3]) / pippo[5];* > * * > *GDALRasterBand* pointerToBand;* > * * > *pointerToBand=pointerToDataSet->GetRasterBand(1);* > * * > *float *elevation;* > * * > *pointerToDataSet->RasterIO(?,?, ... , ?);* > *pointerToBand->RasterIO(?,?, ... , ?);* > > > I supposed I had to store elevation data into the buffer I created, I mean > the float pointer. > I got confused among these: > - the file *.dt0 > - longitude and latitude > - parameters for RasterIO() > > Every tips will be very appreciated, thanks a lot for your patience, > Regards, > Carmelo > > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev > -- Best regards, Chaitanya kumar CH. /tʃaɪθənjə/ /kʊmɑr/ +91-9494447584 17.2416N 80.1426E
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