[pdal] About litree filter: too much computation time, and other questions.

[Ulises Ibarra]

Hello everyone:
I have a few questions about the "litree" filter and the computation time.

After reading the paper: "2021-Li-PERS.pdf" which talks about the "litree"
filter to segment trees, I thought I understood the mechanics of the
"litree" filter, but most likely not.

When applying filters.litree to a file
"L3_0+L3_1_sample_cada_4cm_suelo_dalaunay.las" with 2 million points, the
processing time I have so far is a little over 72 hours.

My pipeline is the following:
{
"pipeline":
[
        {
        "type":"readers.las"
        },
    {
        "type":"filters.litree",
        "min_points":3000,
        "min_height":3.0,
        "radius":2.0
    },
    {
        "type":"writers.las",
        "minor_version":4,
        "scale_x":"0.001",
        "scale_y":"0.001",
        "scale_z":"0.001",
        "extra_dims":"all"
    }
]
}

But I applied previous pipelines to identify where in the process I'm
missing:

L3_0.las +L3_1.las
|
(filters.merge) (1)
|
L3_0+L3_1.las
|
(filters.sample) (2)
|
L3_0+L3_1_sample_cada_4cm.las
|
(filters.elm+filters.outlier+filters.smrf) (3)
|
L3_0+L3_1_sample_cada_4cm_suelo.las
|
(filters.hag_delaunay+filters.sort,dimension:HeihtAboveGround,order:DESC)
(4)
|
L3_0+L3_1_sample_cada_4cm_suelo_dalaunay.las (Here is where I am)
|
(filteres.litree) (5)
|
L3_0+L3_1_sample_cada_4cm_suelo_dalaunay_litree.las (This is where I want
to arrive)

*Questions:*

1. What could I be doing wrong?
2. Does the "radius" option refer to the "spacing threshold" they talk
about in the paper? I set radios:2. May be I wil  a get a
3. I set the value of min_points to 3000, thinking that any cluster of
points better than that value would not be considered and would facilitate
the computation. I'm wrong?


I hope you can help me. I feel really confused.

Tthak you.

Ulises M. Ibarra
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