applying delineate_crowns() to lascatalog

[albatty]

I have successfully applied dalponte2016 to a LAScatalog file to segment trees. I am now trying to extract the crowns as polygons and export them as a shape file. However delineate_crowns() does not work with LAScatalog, only on a las/laz file. Is there an alternative to extract the polygons?

Cheers:)
Robin

[Jean-Romain]

Which version of the package are you using? What does "it does not works" means?

[albatty]

I'm using 4.0.1. I am getting the error:

Error in lazyeval::f_capture(func) : Promise has already been forced

In the documentation it states delineate_crowns() takes and 'object of class LAS*'.

[Jean-Romain]

Please show your code. Is func and expression? The doc states LAS* which means LAS, LAScatalog or LAScluster. It also states that this function is deprecated. Yet it should works.

[albatty]

performing the segmentation

opt_output_files(ctg_norm) <- paste0(tempdir(), "/{*}_segmented")
dalponte <- dalponte2016(chm, th_tree = 4, ttops, max_cr = 25)
ctg_segmented <- segment_trees(ctg_norm, dalponte)

this is the line that is giving the error message

dalponte_crowns <- delineate_crowns(ctg_segmented) %>% st_as_sf(dalponte_crowns)

[Jean-Romain]

You found a bug

[Jean-Romain]

See #594 . As a temporary workaround you can compute a dummy metric

dalponte_crowns <- crown_metrics(ctg_segmented, func = ~list(0))