GeoTiff from LAS Gap handling...

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gphysono
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Joined: Fri Oct 06, 2017 1:57 pm

GeoTiff from LAS Gap handling...

Postby gphysono » Tue Oct 10, 2017 10:03 pm

I have been rasterizing some las files and found something odd. All my geoTiffs have a lot of pixels that are defaulting to min height value - despite me setting options otherwise. Basically it seems that if a GeoTiff pixel doesn't have any Lidar sample points that fall within it, it gets assigned min value?

What I would like is a geoTiff where all pixels have some value, but no matter how I set the options I always get "dead points" in the result.
What is the procedure for making a geotiff where all the height pixels are derived from nearby sample points? I've tried resampling, different sizes and even tried to convert a mesh to Geotiff.. Arg!

Thanks

daniel
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Re: GeoTiff from LAS Gap handling...

Postby daniel » Wed Oct 11, 2017 7:06 am

Indeed, when exported to geotiff, empty cells are set to something close to the minimum height (must be 'min height - 1' if I remember well) and we also set the 'empty cell value' of the geotiff to this value (so that softwares that handle this (non standard) parameter can properly handle the corresponding cells.

If you want to avoid this, you have to set the 'fill empty cell values' option of the Rasterize dialog to 'interpolate'. However it only works inside the convex hull of the raster (there's no clean way to handle the points outside).
Daniel, CloudCompare admin


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