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2

You are looking for GDALRasterBand::RasterIO. For efficiency, if you are indexing multiple points, you will want to read data in blocks then index into the resulting array


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You can do something similar using gdal_calc.py, e.g.: gdal_calc.py -A dtm.tif --calc='((A>=100)*(A<=200))*A+((A<100)*0)+((A>200)*0)' --outfile=dtm_reclass.tif --NoDataValue=-32767 This calc expression would: Assign a value of 0 to all pixel values less than 100 ((A<100)*0) Assign a value of 0 to all pixel values greater than 200 ((A>...


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First of all, if you want to work with heights, normalize the LiDAR point cloud. You have a dense point cloud (4 pts/m²) and also high resolution aerial photos, hence, as you said getting the outside roof perimeter is not an issue. Therefore, assuming you'll manage to have a shapefile with the outer roof boundaries, use it to horizontally clip the point ...


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I've done some environmental consultation on that area and the best available resolution for a DEM there is probably the ASTER GDEM 30m. Even then, that data isn't processed/cleaned so you might run into problems with clouds/reflective surfaces giving you false values. The thing with Lidar is that it costs quite a bit of money to produce and while some ...


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I would try to add a low resolution DEM (e.g. SRTM 30m) to fill the gaps where your high resolution DEM is not available. The problem with a crop before orthorectification is that the RPC link image coordinates with ground, so if your image is not georeferenced and you crop it, this relationship will be detroyed.


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If you have SAGA installed, try to use Fill Sinks as an alternative, and see if this tool can solve your problem. The tool can be accessed from Processing Toolbox -> SAGA -> Terrain Analysis -> Hydrology -> Fill Sinks.


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You can use Saga "Upslope area" geoalgorithm. You must install Saga and configure the path where you installed Saga inside QGIS in Processing->Options or Ctrl+Alt+C. Then expand Providers->Saga, set up the folder and mark Active. If you installed through osgeo4w you just need to restart qgis and you should be done. Then open up the toolbox Ctrl+Alt+...


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I used GIMP plugin wavelet noise reduction tool and I get good results and fast: GIMP Plugin Wavelet noise reduction


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I'm not sure if you can do this with any of the gdal cli tools, but I wrote something in python which accomplishes it: from osgeo import gdal from osgeo.gdalconst import GDT_Float32 import sys import numpy as np def fix_dem_nodata(raster_input, raster_output, nodata=0, threshold=-900): try: in_data, out_data = None, None # open ...


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So just in case someone else encounters the same problem: this seems to work ! CREATE OR REPLACE FUNCTION drape(my_wkt text) RETURNS geometry AS $$ DECLARE geom3d geometry; BEGIN WITH line AS (SELECT my_wkt::geometry as geom), linemesure AS -- Add a mesure dimension to extract ...



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