LAS/Z to XYZ

[Christopher Schildmeier]

Good morning everyone, this is my first post...and my first encounter with LIDAR data.  I've recently been tasked with getting LIDAR data into PLS-CADD(a program that's also brand new to the company).  So far I've been given a .LAZ file(130Mb), from there I used laszip.exe to decompress the file into a .LAS file(890Mb).  I can, and did successfully create a point cloud in Civil 3D using the .LAS, however that's not my end goal. 

As this LIDAR data and our job is specific to Power poles/lines, I need to get the data into PLS-CADD.

From what I've gathered so far, PLS-CADD only opens .xyz files, or it's specific .pls file format.  I won't pretend to know how to use that program at all, I could definitely be missing something.  That being said...if I could simply get this LIDAR data converted to .xyz I "should" be able to open it easily.  I downloaded the full LAStools package, and tried a few of the different .exe's in there.

This is the error I get when using las2dem(outputs .xyz):

"Please note that LAStools is not "free" (see http://lastools.org/LICENSE.txt)

contact 'martin....@rapidlasso.com' to clarify licensing terms if needed.

las2dem -i "z:\Chris\FE\TL682_Cropped.laz" -elevation -odir "z:\Chris\FE" -o "test.xyz" -sp83 CA_VI -survey_feet -elevation_survey_feet -vertical_navd88

Please note that LAStools is not "free" (see http://lastools.org/LICENSE.txt)

contact 'martin....@rapidlasso.com' to clarify licensing terms if needed.

using state plane 'CA_VI' (NAD83 LCC) 'NAD83 / California zone 6'

WARNING: unlicensed. over 1.5 million points. inserting black diagonal.

ERROR (TINclean): failed malloc for 62112574 TINtriangles.

ERROR: cannot alloc enough TIN triangles to triangulate 31056287 points.

       contact martin....@rapidlasso.com for help on what to do"


Am I even close to the right track?  Is this just a licensing issue?

Thank you very much for any input,

-LIDAR newb 

[Martin Isenburg]

Hello Christopher,

I am not familiar with the PLS-CADD software but I hope it was not too expensive as it cannot even handle LAZ ... (-; Seriously. Can it handle point clouds? The XYZ fomat is often used to refer to a raster that is represented as a gridded point cloud where the (usually implicit) x and y coordinate of each raster center are listed explicitly. Here a simple example that shows that the XYZ file is simply an explicit listing of the 5 by 5 grid as 25 points whose x and y coordinates are on located on a 5 by 5 grid.

E:\LAStools\bin>lasgrid -i ..\data\fusa.laz -average -step 50 -o fusa_lowest_50m.xyz
E:\LAStools\bin>lasgrid -i ..\data\fusa.laz -average -step 50 -o fusa_lowest_50m.asc
E:\LAStools\bin>more fusa_lowest_50m.asc
ncols 5
nrows 5
xllcorner 277750.000000
yllcorner 6122250.000000
cellsize 50.000000
NODATA_value -9999.0
44.58 46.09 46.57 49.34 50.83
44.79 46.14 47.15 50.33 51.82
44.46 45.97 47.09 49.47 50.36
49.85 52.59 47.20 49.35 50.22
45.68 45.52 47.70 49.28 50.00
E:\LAStools\bin>more fusa_lowest_50m.xyz
277775,6122475,44.58
277825,6122475,46.09
277875,6122475,46.57
277925,6122475,49.34
277975,6122475,50.83
277775,6122425,44.79
277825,6122425,46.14
277875,6122425,47.15
277925,6122425,50.33
277975,6122425,51.82
277775,6122375,44.46
277825,6122375,45.97
277875,6122375,47.09
277925,6122375,49.47
277975,6122375,50.36
277775,6122325,49.85
277825,6122325,52.59
277875,6122325,47.20
277925,6122325,49.35
277975,6122325,50.22
277775,6122275,45.68
277825,6122275,45.52
277875,6122275,47.70
277925,6122275,49.28
277975,6122275,50.00

If your PLS-CADD software can handle *any* point cloud in ASCII format where the coordinates are listed XYZ then simply use las2txt instead:

E:\LAStools\bin>las2txt -i ..\data\fusa.laz -o fusa.xyz -sep comma
E:\LAStools\bin>more fusa.xyz
277999.97,6122342.20,64.35
277999.97,6122342.53,64.30
277999.52,6122339.74,63.09
277999.55,6122340.05,62.88
277999.53,6122340.41,63.00
277999.53,6122340.75,63.04
277999.55,6122341.07,62.86
[...]

If it can handle only gridded points (aka rasters) then try using the BLAST extension of LAStools.

http://rapidlasso.com/BLAST
http://rapidlasso.com/blast2dem
http://lastools.org/download/blast2dem_README.txt

The ERROR you are seeing has to do with the fact that las2dem is limited to 20 million points per file:

blast2dem -i "z:\Chris\FE\TL682_Cropped.laz" -elevation -odir "z:\Chris\FE" -o "test.xyz"

But there is no need for -sp83 CA_VI -survey_feet -elevation_survey_feet -vertical_navd88 to generate this XYZ tile. This would only be needed if you also need a corresponding PRJ file.

Regards,

Martin @rapidlasso

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