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11 votes
Accepted

Is there a major drawback of working with compressed LAZ vs. the uncompressed LAS?

Although I personally didn't feel a major difference in speed, apparently there IS a major increase of read and write time when using LAZ. Once again the lidR doc is an excellent source of information ...
Honeybear's user avatar
  • 2,464
8 votes

Converting LiDAR files from LAZ to LAS format

For running LASzip from the command prompt window it is also necessary to specify the path of the input file. For example, suppose the laszip.exe file is installed under the drive D: (D:\LASzip\...
Andre Silva's user avatar
  • 10.3k
7 votes

Why did Esri create .zlas compressed LiDAR files instead of adopting .laz?

I can see no technical reason for ESRI's creation of zLAS. A decision was made that - as far as I understand - was quite heavily contested even within the ESRI management to create a format under ...
LAStools's user avatar
  • 1,184
6 votes
Accepted

Accessing raw data from LAZ file in Python with Open Source software?

A convenient way to get point cloud data to Python is to use the PDAL Python extension. PDAL uses the concept of pipelines (much like a GDAL VRT for point clouds instead of rasters) to allow users ...
Howard Butler's user avatar
4 votes

Is there a major drawback of working with compressed LAZ vs. the uncompressed LAS?

@Honeybear's answer is the right one, but with one important caveat – use LAS if you need to touch all of the points. If you don't need to touch all of the points, LAZ-based COPC can be much better. ...
Howard Butler's user avatar
4 votes
Accepted

Convert .LAZ to .LAS without LAStools or command line (QGIS 3.22.4)?

I believe it will be possible when PDAL 2.4.0 is released and when QGIS starts to use it. From the PDAL mailing list: We are now in the release freeze period for the PDAL 2.4.0 release. Some upcoming ...
user30184's user avatar
  • 67k
3 votes
Accepted

PDAL crashes when trying to filter noise points from outliers filter

This file is strange. First, an EPSG code of 0 isn't valid. LOCAL_CS["unnamed",AUTHORITY["EPSG","0"]] Second, SMRF is designed for aerial LiDAR data, not this (bridge superstructure?). Third, ...
Howard Butler's user avatar
2 votes

Finding the origin in .laz file with LAStools

The sample record you show is in projected coordinates and the two values for longitude and latitude listed in the Coordinate Reference System (CRS) are part of the parameters that defined the ...
LAStools's user avatar
  • 1,184
2 votes

Converting LiDAR files from LAZ to LAS format

To run laszip in a command prompt in Windows you need to use the "-i" paremeter to specify your input files: laszip -i lidar.laz or laszip -i *.laz To run the above commands Laszip must be in your ...
berniejconnors's user avatar
2 votes

Converting LiDAR data (.laz) to DSM in .asc format

One caveat to using FUSION: it truncates the precision of the output coordinates to only 4 decimal places, and I required 6. I really wanted to use WhiteBox GAT, however I was unable to get it to ...
CableBox's user avatar
2 votes
Accepted

LAS/LAZ parser for NodeJS

https://github.com/hobu/laz-perf contains an alternative implementation of LASzip that can be compiled to WASM and JavaScript using Emscripten. It is used by Potree and PlasioJS to provide LAZ support ...
Howard Butler's user avatar
2 votes

Add default classification to Esri ASCII Raster?

The Welsh website allows you to download DTM and DSM in ASCII format. It is not raw lidar data. Classification of lidar data as I understand it is found in data that is in LAS format not ASCII. ESRI ...
Hornbydd's user avatar
  • 43.8k
2 votes

Writing LAZ file using laspy

https://github.com/grantbrown/laspy says Laspy is a pythonic library for reading, modifying and writing LAS files. Support for LAZ is limited to reading LAS version 1.0-1.3 files. laspy does not ...
bugmenot123's user avatar
  • 10.9k
2 votes

Laspy - Laszip & TypeError

There is some kind of a recession with the latest numpy. See https://github.com/laspy/laspy/issues/112#issuecomment-583180711 for details.
Howard Butler's user avatar
2 votes
Accepted

What is the most efficient way to write COPC files with PDAL

Your definition of efficient is memory efficient. Untwine spools a disk cache instead of using memory to sort and build the COPC file. You can control how much disk cache it uses by selecting which ...
Howard Butler's user avatar
1 vote
Accepted

Loading laz point cloud in QGIS error: Invalid Data Source

I also couldn't load "bad" into QGIS 3.22.16. I drag-n-dropped into and then re-saved "bad" in CloudCompare, compressed to LAZ in Las2Las(this step probably unneccessary), and then ...
Pointdump's user avatar
  • 1,055
1 vote
Accepted

Converting LAZ to LAS using laspy

This isn't a python fix, but in ArcPro you can just use the Convert LAS tool. I find even though its an optional parameter, you just need to make sure the coordinate system is set and it works great!
Jessica's user avatar
  • 96
1 vote

GRASS GIS problem with r.in.pdal

Yes, you spotted a bug which we have fixed a few days ago (commit reference). Simply reinstall the r.in.pdal command with g.extension to fetch the updated version.
markusN's user avatar
  • 13k
1 vote

Error when unzipping LiDAR data with LAStools

Might be a very basic one, but I just ran into it. I forgot to unzip the LASTools files in C:\ (hence the C:\LASTools folder didn't exist) before I installed it as a QGIS plugin. After unzipping ...
Márton Deák's user avatar
1 vote

Further compression of LiDAR data besides LASZip

There are things you can do to the files before you compress them to make the LAZ compression more efficient. Sort them based on GPSTime if you have that attribute. Sort them along a space-filling ...
Howard Butler's user avatar
1 vote

Further compression of LiDAR data besides LASZip

To answer your first question: No. The tools and supporting documentation over at LASzip.org covers the details. A lossless compression is absolutely critical with LAS data and this group has ASPRS ...
user23715's user avatar
  • 792
1 vote
Accepted

Optimizing workflow for FUSION's PolyClipData?

Use Fusion's LTKProcessor to speed up performance of PolyClipData. It is described in Appendix C from Fusion's manual (emphasis mine): Using LTKProcessor to Process Data for Large Acquisitions ...
Andre Silva's user avatar
  • 10.3k
1 vote

error: Compression support not enabled in liblas configuration

The way I see liblas installed from brew, it does not include flags WITH_LASZIP or WITH_STATIC_LASZIP on build. See: https://github.com/Homebrew/homebrew-core/blob/master/Formula/liblas.rb
winsent's user avatar
  • 366
1 vote
Accepted

Converting LiDAR data (.laz) to DSM in .asc format

As mentioned by Aaron, the CanopyModel tool from Fusion can build Digital Surface Models (DSM). In order to directly use the compressed LiDAR files .laz as input of CanopyModel, it is necessary to ...
Andre Silva's user avatar
  • 10.3k
1 vote

Batch processing las files with LASzip from QGIS?

Check this tutorial on Batch Processing using Processing Framework. For loading multiple files, the key is In the Batch Processing dialog, the first tab is Parameters where we define out inputs....
underdark's user avatar
  • 84.2k
1 vote

Difference in the elevations for the same building on two DSMs saved in *.asc and *.laz formats

I couldn't even reproduce the inconsistency in the heights between the .laz and the .asc files, as the .laz file opened in ENVI LiDAR is now showing elevation values consistent with what shown in QGIS ...
Hakim's user avatar
  • 956
1 vote

Converting LiDAR files from LAZ to LAS format

It seems you are running on windows. Simply double-click the laszip.exe program and operate it via the GUI. You can browse to the folder you want to decompress via the 'browse...' rollout on the left ...
LAStools's user avatar
  • 1,184
1 vote

Laz LiDAR files displaying extremely long thin line of points

I experienced the same problem with .laz files distributed on NOAA's S3 server for example https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/6325/Delivery_1/44123D8224.laz, which I ...
Max Ogden's user avatar
  • 152

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