[pdal] Performance Question

[Howard Butler]

> On May 21, 2024, at 1:57 AM, Dan Mullins via pdal <pdal at lists.osgeo.org> wrote:
> 
> Hello - 
> 
> We would like to store our data (points + point specific data) in an Entwine point cloud. We've been testing a subset (~35m points) and noticed some strange performance. When we give the reader.ept a polygon, the response time for just X/Y/Z data is really fast. It returns ~15k points in 1s. When we create the ept with our additional data attributes (8 total), it slows down to 6s. Is this expected? If so, are there ways to improve the performance?

Extra byte dimensions in LAZ are poorly compressed, so it might be that you're simply fetching a lot more bytes. Maybe it makes more sense to use EPT Addons https://pdal.io/en/latest/stages/writers.ept_addon.html instead of extra byte dimensions.

> Can we pick which columns of data we want returned?

Selective access and decompression is something that's possible but not yet implemented. 

Howard

PS, do note that you are going to quite quickly move from help-us-with-open-source-software to consult-with-us-to-tell-us-how-to-exploit-this-software-the-best with this topic. 
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