[pdal] (no subject)

[Howard Butler]

count includes everything in the interpolation radius.

Use binmode=True on writers.gdal if you want the points only in the pixel. It is discussed in more detail in the docs at https://pdal.io/en/latest/stages/writers.gdal.html 

Howard


> On Dec 14, 2023, at 11:57 AM, lefsky--- via pdal <pdal at lists.osgeo.org> wrote:
> 
> I wrote the following code to calculate point density. While it produces results that have the correct spatial pattern, the absolute values appear to be incorrect. The image is 3938 pixels by 3938 pixels and the mean pixel value is 32.8, so the total number of points from the PDAL calculation is  
> 
> 3938*3938 * 32.8 = 483403808.8 
> 
> but there are only 164022975 points in the original laz file, so the estimate of 483403808.8 is just about 3 times larger than the number of points in the las (2.947 top be exact) 
> 
> Or have I misunderstood something?
> 
> M
> 
> Image Statistics:
> 

> json:
> 
>   "pipeline":[
>     {
>         "type":"readers.las",
>         "filename":"/home/lefsky/time_trials/tile_67_136_sub_2.laz"
>     },
>     {
>         "type":"writers.gdal",   "filename":"/home/lefsky/time_trials/tile_67_136_sub_2_density.tif",          "dimension":"Z",
>         "data_type":"Float32",
>         "output_type":"count",
>         "resolution": 1
>     }
>   ]
> }
> 
> 
> 
> 
> 
> --
> Michael Lefsky (He/His) 
> Home Location: HVHF+GH
> Cell: 970-980-9036
> http://www.researcherid.com/rid/A-7224-2009
> 
> “for being prematurely, and worse, intuitively right — there’s a heavy price. But for being wrong — no, not so long as you’re wrong in a pack." Gary Brecher / Portis
> 
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> 
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