[pdal] count option with .ept files

[Connor Manning]

The EPT reader currently doesn't respect the `count` option at all.  This
is a default reader option inherited by all readers, which is why it
appears in the docs even though the EPT reader itself doesn't use it.

For now, the only possibility would be limiting EPT reads by bounds or
resolution, and then using the head filter to limit the point count exactly.

This would be worthy of an issue on PDAL's github if you'd like to track
the status of adding support for the `count` option by the EPT reader.

- Connor

On Thu, Feb 21, 2019 at 6:24 PM Matt Beckley <beckley at unavco.org> wrote:

> Hello all,
>
> I would like to limit the number of points read from a .ept file - or at
> least get a notification if the number of points is greater than a certain
> number.  The "count" option seems to be what I want, but it doesn't seem to
> work as I expected.  Here is my pipeline:
>
> {
>>   "pipeline": [
>>     {
>>       "type": "readers.ept",
>>         "filename": "ept://
>> https://s3-us-west-2.amazonaws.com/usgs-lidar-public/USGS_LPC_MD_VA_Sandy_NCR_2014_LAS_2015
>> ",
>>         "bounds": "([-8577627, -8575100], [4705400,4706300])",
>>       "count":"25"},
>>       "test_DC_25Pts.laz"
>>   ]
>> }
>
>
> This will run without errors, but the "count" option never seems to be
> read.  I've tried with and without quotes.
>
> However, when I run a similar pipeline on a local las file, I am able to
> limit the number of points in the output file.  For example:
>
> {
>>   "pipeline": [
>>     {
>>       "type": "readers.las",
>>         "filename": "C02_ns.las",
>>       "count":250},
>>       "test_250Pts.laz"
>>   ]
>> }
>
>
> This produces an output LAZ file with only 250 pts - as I expected.
>
>
> When using reader.ept does the count refer to the number of tiles, and not
> actual data points?
>
>
> Any info would be appreciated.  Thanks for your time,
>
>
> matt.
>
>
> ---------------------------
> Matthew Beckley
> Data Engineer
> UNAVCO/OpenTopography
> beckley at unavco.org
> 303-381-7487
> _______________________________________________
> pdal mailing list
> pdal at lists.osgeo.org
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