clip LiDAR data by plot

[Dwight Crouse]

Hi Martin,

When doing a lasclip command, is there a way to retain a plot-id in the that is stored in a shapefile attribute field, putting that plot-id in the resulting filename of the clipped LiDAR data?  Looking at the read-me file maybe I just missed something?  Seems like something that would be extremely helpful.

Dwight

[Tobias K Kohoutek]

I would like to give this topic a push and add lascanopy to also name the resulting files (if one choses height metrics for -lop or each file is a plot) to name the files with an attribute or with the same filename. Right now it counts from 1 to X

Cheers,

Tobias

[Irf]

Hi Tobias,

I have yet to test it using lasclip, but I am sure about 'lascanopy' that you can get names in the output files. All you need to add is '-names' in the command line. It should look something like (also given in the README file):

lascanopy -i *.laz -files_are_plots -int_avg -int_std -cov -gap -names -o output.csv  

Regards,

Irf

[Tobi]

Hey Irf,

cool, I didn't know that. (probably Martin has it in his readme file and I didn't check for it)

Thanks for the hint!

Cheers,

Tobias

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[Paul Magdon]

Hi everyone,

I also like to push this issue. Lasclip runs excelent but when we have a large set of plots e.g. 100 we need to have an option to name the output lasfiles according to an attribute of the polygones e.g. plot_id.

I tested the suggestion to use '-names' but this is not available for lasclip.

Any suggestions?

Greetins Paul

[Martin Isenburg]

Hello from Melbourne,

Good timing. I just finished implementing this and you can help beta-testing this new functionality. Download the updated tool here:

https://www.dropbox.com/s/ljtgi1hrqlb6wzo/lasclip.exe

And then

lasclip -i lotsoflidar/*.laz -merged ^

           -poly myplots.shp ^

           -split SomeName ^

           -odir outputplots ^

           -olaz

Or

lasclip -i lotsoflidar/*.laz -merged ^

           -poly myplots.shp ^

           -split 3 ^

           -odir outputplots ^

           -olaz

Where SomeName is the name of the string field with the output file name or 3 is the index of the string field (count starts at 0) in the DBF file.

Regards,

Martin

[Susana Gonzalez]

Martin,

I have run your script, works great!

Thanks

Susana

[cai...@vicforests.com.au]

Hi Martin,

I did try lasclip using multi plots. The question is that is it possible to name the out put laz file as the same as the clip shapefile's ID?



Regards

Cai Li  I  GIS Analyst, Resources  I  VicForests

Level 12, 461 Bourke Street, Melbourne  Vic  3000  I  G P O Box 191, Melbourne   Vic   3001
T:  +61 03 9608 9571  I   F:  +61 03 9608 9566  I  E:  cai...@vicforests.com.au

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[Susana Gonzalez]

Hi Cai,

Have a look in this email from Martin.

Cheers

Susana

[cai...@vicforests.com.au]

Hi Martin,

When doing a lascanopy command, is there way to put laz filename of input Lidar data in the output csv file?

Regards

Cai Li  I  GIS Analyst, Resources  I  VicForests

Level 12, 461 Bourke Street, Melbourne  Vic  3000  I  G P O Box 191, Melbourne   Vic   3001
T:  +61 03 9608 9571  I   F:  +61 03 9608 9566  I  E:  cai...@vicforests.com.au

[Susana Gonzalez]

Hi again,

You could use the plot name without clipping them

 

Plot list in a txt file: PlotName X Y Radius (space between columns)

 

C:\LAStools\bin\lascanopy.exe -v -i %NORMALISE%\*.laz ^

-names -loc %PLOTS%\Plots.txt ^

-p 25 75 95 ^

-fractions ^

-o %PLOTMETRICS%\Plots_metrics.csv

 

Cheers

Susana

 

From: last...@googlegroups.com [mailto:last...@googlegroups.com] On Behalf Of cai...@vicforests.com.au

Sent: Thursday, 30 November 2017 4:26 PM
To: last...@googlegroups.com

--

[cai...@vicforests.com.au]

Thank you Susana,

Actually, I am using irregular shape polygons to test a lascanopy tool, so have to use clipped lidar point file that named as polygon id.

if without -name and input polygon shape file, the result likes

lascanopy -lof file_list.3192.txt -files_are_plots ^

-all -min -max -avg -std -ske -kur -qav -p ... 25 50 75 90 95 99 ^

-fractions -odir %outputcsv% -ocsv

if i try -name .... as blow

lascanopy -lof file_list.3192.txt -files_are_plots ^

-all -min -max -avg -std -ske -kur -qav -p ... 25 50 75 90 95 99 ^

-fractions -odir %outputcsv% -ocsv ^

-names -lop %polygon%\polyg.shp

the result likes

Regards

Cai Li  I  GIS Analyst, Resources  I  VicForests

Level 12, 461 Bourke Street, Melbourne  Vic  3000  I  G P O Box 191, Melbourne   Vic   3001
T:  +61 03 9608 9571  I   F:  +61 03 9608 9566  I  E:  cai...@vicforests.com.au

From:        Susana Gonzalez <susana....@interpine.nz>
To:        "last...@googlegroups.com" <last...@googlegroups.com>,

[Iain Clarke]

Hi Martin,

I'm also keen to beta-test this mod, but I can't access the link due to the UTAS security systems.

Would you be able to place in a Google Drive folder and forward me the link please? Or some other method to

access the new lasclip.exe?

Cheers,

Iain Clarke

PhD Candidate

University of Tasmania

---

From: last...@googlegroups.com <last...@googlegroups.com> on behalf of Susana Gonzalez <susana....@interpine.nz>
Sent: Thursday, 30 November 2017 7:40 AM
To: last...@googlegroups.com
Subject: RE: [LAStools] Naming clip LiDAR data as plot id

 

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[Martin Isenburg]

Hello Iain,

that tools is already updated in the latest release of LAStools (171124) along with these changes:

24 November 2017 -- lascanopy: use option '-height_in_attribute 0' if height is stored as additional attribute

22 November 2017 -- las2txt: parse extra bytes attributes with indices larger than 9 by bracketing (12) them 

21 November 2017 -- txt2las: allow adding up to 32 (from 10) additional extra bytes attributes

21 November 2017 -- lasclip: use output file name from DBF attribute of SHP file with '-split Plot_Name'

17 November 2017 -- LASlib: new transform '-copy_intensity_into_NIR' (makes only sense for point type 8)

7 November 2017 -- lasthin: new '-gps_time 0.01' thins per 0.01 sec intervals instead of per spatial cells

30 October 2017 -- las2las: new option '-vertical_evrf2007' for European Vertical Reference Frame 2007

26 October 2017 -- lasthin: optional minimum number of points needed for option '-percentile 40 10'

15 October 2017 -- lasclassify: use height above ground from additional attribute with '-height_in_attribute 0'

14 October 2017 -- lasinfo: new WARNING when bounding box in LAS header miss-matches coordinate resolution

reminder again on how to use this new option in lasclip:

 

lasclip -i lotsoflidar/*.laz -merged ^

           -poly myplots.shp ^

           -split SomeName ^

           -odir outputplots ^

           -olaz

 

Or

 

lasclip -i lotsoflidar/*.laz -merged ^

           -poly myplots.shp ^

           -split 3 ^

           -odir outputplots ^

           -olaz

 

Where SomeName is the name of the string field with the output file name or 3 is the index of the string field (count starts at 0) in the DBF file.

[Martin Isenburg]

Hello Cai,

to add the input file name to the output CSV simply add '-names' to the command line.

E:\LAStools\bin>dir plots_0000*.laz

12/16/2017  05:40 AM           161,636 plots_000000.laz

12/16/2017  05:40 AM           112,384 plots_000001.laz

12/16/2017  05:40 AM           119,599 plots_000002.laz

12/16/2017  05:40 AM           164,300 plots_000003.laz

12/16/2017  05:40 AM           131,650 plots_000004.laz

12/16/2017  05:40 AM           120,251 plots_000005.laz

12/16/2017  05:40 AM           127,704 plots_000006.laz

12/16/2017  05:40 AM           100,868 plots_000007.laz

E:\LAStools\bin>lascanopy -i plots_0000*.laz ^

                                            -files_are_plots ^

                                            -names ^

                                            -all -min -max -ske ^

                                            -o plots.csv

E:\LAStools\bin>more plots.csv

file_name,all,min,max,ske

plots_000000.laz,32191,1.37,42.3,-0.86

plots_000001.laz,22234,1.37,39.54,0.47

plots_000002.laz,23827,1.37,38.69,-0.79

plots_000003.laz,32548,1.37,41.92,-1.05

plots_000004.laz,26330,1.37,26.09,-0.72

plots_000005.laz,24508,1.6,43.91,-0.91

plots_000006.laz,25374,1.37,42.06,-0.1

plots_000007.laz,20186,1.39,32.04,-0.51

Regards,

Martin @rapidlasso

[Silvia Losada]

Hello Martin,

I am using LasCanopy GUI and I am having the same issue as Cai.  I have 87 forestry plots that need to be distinguished by plot ID, and I would like the output of lasCanopy to be a single csv file with 87 rows, one row per plot and also have the plot IDs displayed in a column so I can generate correlations with field plots. I have clipped the LiDAR point cloud using a shapefile of the plots so that I have 87 individual las files for each plot. The name of each las file has the corresponding Plot ID. 

When I used the "process all files",  "files_are_plots" and "merged" command, the output of lasCanopy results in a csv file with a single row, it seems like the tool ends once it processes the first las file. So I tried using your suggestion of adding "-names" into the command line but that results in the same thing, except the first column shows the file path of the first las file. If I don't use the "merged" command, the output generates 87 separate csv files with one row each, each csv file name is the plot ID. So I would have to manually copy paste each separate row into a single csv file.

  

On the other hand, I also tried using the plot shapefile instead using the "lop" feature in the following way:  (-lop "E:\\All_Plots.shp"), and the output csv file has all the plots in a single file but does not show the ID numbers (Column A).

 As per the documentation, I also tried using the index number of the ID column of the shapefile's DBF file, with the index being 1, (-lop "E:\\All_Plots.shp" 1) but for some reason lasCanopy cannot read it, I get an error that says: "cannot understand argument '1'. " I suspect this is happening because the 1 is outside the parenthesis, but i also tried with the 1 inside the parenthesis and the error indicates that the file cannot be open. I also used the name of the ID column but the same issue occurs.

Is there a way I can work around this so that I can have a Plot ID column along with the metrics extracted from lasCanopy in a single csv file?

Thank you in advance for your help.

Best regards,

Silvia Losada

On Thu, Nov 30, 2017 at 5:43 AM, <ca...@vicforests.com.au> wrote:

Thank you Susana,

Actually, I am using irregular shape polygons to test a lascanopy tool, so have to use clipped lidar point file that named as polygon id.

if without -name and input polygon shape file, the result likes

lascanopy -lof file_list.3192.txt -files_are_plots ^

-all -min -max -avg -std -ske -kur -qav -p ... 25 50 75 90 95 99 ^

-fractions -odir %outputcsv% -ocsv

if i try -name .... as blow

lascanopy -lof file_list.3192.txt -files_are_plots ^

-all -min -max -avg -std -ske -kur -qav -p ... 25 50 75 90 95 99 ^

-fractions -odir %outputcsv% -ocsv ^

-names -lop %polygon%\polyg.shp

the result likes

Regards

Cai Li  I  GIS Analyst, Resources  I  VicForests

Level 12, 461 Bourke Street, Melbourne  Vic  3000  I  G P O Box 191, Melbourne   Vic   3001

T:  +61 03 9608 9571  I   F:  +61 03 9608 9566  I  E:  ca...@vicforests.com.au

[Irf]

Hi Silvia,

To be able to extract canopy metrics, you do not need to clip your point cloud data to plot boundaries. You can use the following line of code to get your desired output.

lascanopy -cpu64 -i pointcloud.laz -merged -files_are_plots -names -lop your_shapefile_with_all_plots.shp Plot_No -centroids -height_cutoff 0.1 -abv -all -odir path_to_output_directory/ -o output.csv

merged: if you have a tiled or split-by-plot point cloud - observe caution when using tiled point clouds (ref: https://rapidlasso.com/2015/08/07/use-buffers-when-processing-lidar-in-tiles/)

lop: polygon shapefile

Plot_No: name of the field containing plot IDs as it appears in your_shapefile_with_all_plots.shp. An index can be used but that in your case, I believe, might not be 1.

centroids: writes the centre coordinates for each of your plots to the output csv

height_cutoff 0.1: usually a height_cutoff of 1.3 or 2 is used; not sure why you would use a height_cutoff that is below ground. If your point cloud is normalised, which I believe should be, then use a height_cutoff greater than zero.

I hope this helps.

Regards,

Irf