Holes in my DTM

[floraproj...@gmail.com]

Hello

How can I remove these little holes from my dtm. The data is from drone photos. I have open areas for which I want a high resolution. I can't use all the points because there are trees overhanging the edges sometimes.

Any suggestions?

Regards

Cam

lastile -i *.laz -rescale 0.01 0.01 0.01 -tile_size 100 -buffer 10 -odir poop -olaz -cores 23

lassort -i poop/*.laz -odix _s -olaz -cores 23

lasground_new -i poop/*_s.laz -wilderness -compute_height -odix g -olaz -cores 23

lasclassify -i poop/*_sg.laz -odix c -olaz

lastile -i poop/*_sgc.laz -remove_buffer -tile_size 100 -buffer 10 -keep_class 0 1 2 3 9 -odir "k:/uav_process/lastools/bin/poop2" -olaz -cores 23

blast2dem -i poop2/*.laz -step 0.05 -use_tile_bb -obil -cores 23

lasgrid -i poop2/*.bil -merged -step 0.05 -ocut 18  -odix %file_name%_dtm_fine -odir  "k:/uav_process/output/%file_name%" -otif

[Martin Isenburg]

Hello,

wow. You run with '-cores 23' ... ? What kind of monster machine do you have?

(-:

I see that you are keeping several classes '-keep_class 0 1 2 3 9' and some of them seem to be low (or high) noise points that result in these "spikes" that you call "holes". Maybe a lasnoise step will be necessary here. Can you share a sample file?

http://rapidlasso.com/lasnoise

http://lastools.org/download/lasnoise_README.txt

Also, you should not remove the buffers before running blast2dem as this can lead to artifacts along the tile boundary.

https://rapidlasso.com/2015/08/07/use-buffers-when-processing-lidar-in-tiles/

Here an updated (but untested) workflow:

lastile -i *.laz -rescale 0.01 0.01 0.01 -tile_size 100 -buffer 10 -odir poop -olaz -cores 23

lassort -i poop/*.laz -odix _s -olaz -cores 23

lasnoise -i poop/*_s.laz -odix n -olaz -cores 23

lasground_new -i poop/*_sn.laz -ignore_class 7 -wilderness -compute_height -odix g -olaz -cores 23

lasclassify -i poop/*_sng.laz -odix c -olaz -cores 23

blast2dem -i poop/*_sngc.laz -keep_class 0 1 2 3 9 -step 0.05 -use_tile_bb -obil -cores 23

lasgrid -i poop/*_sngc.bil -merged -step 0.05 -ocut 19 -odix %file_name%_dtm_fine -odir "k:/uav_process/output/%file_name%" -otif

Regards,

Martin @rapidlasso

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