Invalid polygons

[djes]

Hello,

When using crown_metrics() or delineate_crowns() to create convex or concave polygons, I sometimes encounter the 'invalid polygon created. They likely correspond to trees with aligned points.' problem coming from the metrics_crowns.R code, and processing halts. As I have tried everything to filter out problematic data and all parameters, I'm stuck to manual edition.

Does someone have an idea? I've tried to create my own function but I'm not at ease with R.

I also wonder if it could be possible to use the st_make_valid() somewhere in the metrics_crowns.R code to, at least, not stop the processing ?

Regards,

J.B.

crown bug example

[Jean-Romain]

Please report a minimal reproducible example.

[djes]

Of course

las <- readLAS("probleme.laz")
pol = crown_metrics(las, func = .stdmetrics, geom = "convex")

With the following file probleme.laz

[Jean-Romain]

I can't see any problem here. You have a indeed message. But it is only a message.

valid <- sf::st_is_valid(pol)
pol[valid,]

[djes]

Sorry, I have not mentioned that the main problem is with a catalog, as the processing stops on the faulty tile and nothing is generated for the faulty tile. I can make a small example with a catalog if you want.

[Jean-Romain]

What is the error ? I mean, you only have a message here no error. Or maybe sf fails at writing the file ?

[djes]

Here is the error message

pol = crown_metrics(ctg, ~list(0, z_max = max(Z)), geom = "convex")

  |                                                                         
  |                                                                   |   0%
  |                                                                         
  |======================                                             |  33%Erreur : Evaluation error: IllegalArgumentException: Invalid number of points in LinearRing found 3 - must be 0 or >= 4.

I've rapidly created a small working example with 3 "small" faulty las files : https://drive.google.com/file/d/1y4w1EqWfNdMMXpW2gfN2QGyWjLzYrAdb/view?usp=share_link

[flottsam]

Did you ever find a solution? I'm receiving a similar error with warning message too:

scan() expected 'a real', got 'IllegalArgumentException:'

Error in any_list[[1]] : subscript out of bounds
In addition: Warning message:
4 invalid polygons created. They likely correspond to trees with aligned points.