[pdal] "resolution" keyword in

[Jim Klassen]

My understanding is that it isn't griding or making up new points or aggregating points or anything like that.  It returns a subset of the original points.  Which points it returns depends on what level of the ept tree that each of the original points was placed into when the tree was created.  The resolution parameter determines how many levels of the tree PDAL pulls points from.

As far as I can tell it takes no regard for non-spatial dimensions such as classification.  So, there isn't a direct way to for example query for only ground points at a certain resolution.  You have to query for all points and then filter out the ones that aren't ground (which will likely leave you with a lower resolution than you initially queried for in your final result).

On 3/25/19 1:48 PM, Matt Beckley wrote:
> Is there more information available regarding how the 'resolution' keyword works for the latest version of readers.ept?  Is it "gridding" the data at a specified cell size?  If so, how does it handle nominal class data such as lidar classifications?  Is it taking the first, last, or a random sample to assign as the classification for each cell(assuming a scenario where there are multiple classifications that fall within a given cell).  In other words, how is the defining classification assigned for each cell given a sample of points with varied classification values?
>
> https://github.com/PDAL/PDAL/blob/master/doc/stages/readers.ept.rst
>
> Thanks!
>
> matt.
>
> ---------------------------
> Matthew Beckley
> Data Engineer
> UNAVCO/OpenTopography
> beckley at unavco.org <mailto:beckley at unavco.org>
> 303-381-7487
>
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