What are the integer data in UserData column of output from webODM?

The odm_georeferenced_model.las output from webODM reconstruction of RGB drone images (not lidar) has all zeros in the classification column (even though my input settings set pc-classify = TRUE). The UserData column has non-zero data. I do not know what these UserData represent? They look like they might classification of ground, vegetation, etc?

Sample output in the odm_georeferenced_model.las is pasted below

lasGroundPMF_Q1@data[[“UserData”]]
[1] 2 2 2 3 3 2 2 3 2 2 4 3 2 2 3 2 2 3 2 3 2 2 2 2 2 2 3 2 2 2 5 2 2 3 6 2 2 2 7 2 2 2 2 2 2 3 2 2 3 3 2 2
[53] 2 3 2 2 2 4 3 5 3 2 2 3 2 3 2 6

For non-lidar sensors, I am assuming, that the output from webODM is not going to have any classification?

Thank you any help or guidance you can provide,

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Welcome!

The --pc-classify tag is influenced by the Simple Morphological Filter that is used to generate the DTM. I think you’ll find with the default settings you’re mostly going to have Unclassified/0 for most of it, unless your dataset has some really dynamic elevation and structure changes.

https://docs.opendronemap.org/arguments/pc-classify/

As for the userdata column, I am not sure at the moment.

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Yes, to better understand smrf, check out the PDAL documentation on it:
https://pdal.io/stages/filters.smrf.html

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UserData contains the number of views (cameras) that a point has been seen by. It’s mostly used internally to generate our coverage report diagram.

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Thank you everyone for the great help in explaining what the UserData column data in the output .las file means, and the classification values for photogrammetry.

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