[pdal] (no subject)

[lefsky at gmail.com]

Thanks for the clarification.

On Thu, Dec 14, 2023 at 11:00 AM Howard Butler <howard at hobu.co> wrote:

> 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:
>
> [image: image.png]
>
> 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*
>
> *I acknowledge that I live and work on stolen land. This is the land of
> the Cheyenne, Arapaho, Ute, and Ocheithi Sakowin people. To learn more
> about these nations, please visit;
> http://www.utemountainutetribe.com/
> http://www.cheyennenation.com/
> https://cheyenneandarapaho-nsn.gov/
> https://native-land.ca/
>
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>

-- 
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*

*I acknowledge that I live and work on stolen land. This is the land of the
Cheyenne, Arapaho, Ute, and Ocheithi Sakowin people. To learn more about
these nations, please visit;
http://www.utemountainutetribe.com/
http://www.cheyennenation.com/
https://cheyenneandarapaho-nsn.gov/
https://native-land.ca/
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