laslazlidarnode-js
I cannot find any popular libraries for parsing (reading into memory) of LAS or LAZ (lidar data) files in NodeJS (desktop Javascript)
https://github.com/yuyou/liblas4node/blob/master/lib/liblas.js
This depends on liblas which is deprectaed/replaced by PDAL, for which, no js bindings exist. Are there any other libs out there? npm search is a little clusmy, since 'las' is found in many completely non related packages
This is because csc.noaa.gov lidar files are stored with the .laz file format extension. It is a compressed version for .las extension.
Read this* article to know more about compressed las files (.laz).
In order to correctly visualize these types of files, you need to retransform them from .laz to .las. Use the open-source LiDAR compressor LASzip to accomplish this task.
Here is one example:
Suppose that LASZip is installed under the drive C:, and the .laz file is stored under a fold named project (C:\project). Do the following:
c:\LASZip\laszip -i c:\project\aaa.laz -o c:\project\aaa.las
aaa is just a name for the file which I have made up. Here is more some tips from Bruce Simonson about potentializing the use of LasZip .
*Reference
ISENBURG, M. LASzip: lossless compression of LiDAR data, 2012.
Examples
See below some examples about how .laz files become disfigured in comparison with its uncompressed version .las.:
This is the Fugro Viewer. While the dots in the .las file are concentrated in the upper and lower layers in the z direction (left panel), the dots in the .laz version are more homogeneously spread (right panel).
This is the Quick Terrain Reader. The dots in the .laz file are flattened in the z direction (right panel).
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\laszip.exe) and that the .laz files are stored in D:\lidar.
Then, type:
D:\LASzip\laszip D:\lidar\*.laz
It will decompress all LAZ files in the current folder overwriting any existing file. The output files will have same name as the input files (but with extension .las).
Some remarks:
-i for input parameter, but it is optional: D:\LASzip\laszip -i D:\lidar\*.laz.-odir can be used to specify a different output folder: D:\LASzip\laszip -i D:\lidar\*.laz -odir D:\lidar\output. It will save all .laz files with the same file names (except for .las extension) in the specified output folder. See Saving LAZ files to different location from input (LAS) files?.-odix to append to output file names: D:\LASzip\laszip -i D:\lidar\*.laz -odir D:\lidar\output -odix _decompressed. It means if the input file name is point_cloud_27.laz, the output file name will be point_cloud_27_decompressed.las.See more examples here.
Another option (in relation to first example) is to proceed as suggested by Barbarossa, i.e., open the cmd from the input file folder and write the command as in your first attempt.
REM move to folder where the input file is, then run laszip.
cd D:\lidar
D:\LASzip\laszip *.laz
If you want to call laszip directly from any folder without specifying the program path, then, berniejconnors's answer gives a good hint to add it in the environment variables (see here).
laszip D:\lidar\*.laz
All examples here work the other way around, i.e., converting from .las files to .laz.
Best Answer
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 in JavaScript.