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11 votes

What LiDAR processing tools are available in Python?

I have recently released an open-source (MIT) stand-alone (i.e. no dependencies) library called WhiteboxTools for performing many types of geospatial analysis, including LiDAR data processing. The ...
WhiteboxDev's user avatar
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
9 votes

Converting between coordinate systems for LAS file using LASPY

You should check what the scale and offset are for your file. This can be done as follows: van_taken.header.scale van_taken.header.offset This almost looks like an overflow error to me. The lower ...
Grant Brown's user avatar
9 votes
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Converting .las to .pcd file using PDAL?

The PDAL PCD Writer can write .pcd files. For it to work, you must have linked the PCL libraries at compile time. The PDAL OSGeo4W build does not have PCL support. If you are unable to build PDAL with ...
Howard Butler's user avatar
9 votes

Python-PDAL: error reading Format 1.4 LAS File - (readers.las Error) Global encoding WKT flag not set for point format 6 - 10

I hope this provides a bit more context for the original question and helps anyone who comes here in the future: For LAS 1.4 using Point Data Record Format 6 - 10, the Global Encoding (GE) flag must ...
peterwjacko's user avatar
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
8 votes

Explaining laser scanning distortions on water surfaces?

In some cases, water will reflect the LIDAR beam away from the sensor (specular effect at some incidence angle) or absorb all its energy (water has a low reflectance in near Infrared.) As a results, ...
radouxju's user avatar
  • 49.7k
8 votes
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Convert WKT coordinate reference system to PROJ4

Use the rgdal package and showP4: Your string: > ps [1] "COMPD_CS[\"Projected\", PROJCS[\"UTM_10N\", GEOGCS [ \"WGS84\", DATUM [ \"WGS84\", SPHEROID [\"WGS 84\", 6378137.000, 298.257223563 ], ...
Spacedman's user avatar
  • 64.4k
7 votes
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How does the offset values of LAS files relate to their coordinate system?

This got me thinking, how (if any) does the offset of an LAS file relate to the coordinate system that it is projected to? They don't really relate to the coordinate system. The offset (in ...
Howard Butler's user avatar
7 votes
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Rescaling and reoffsetting a point cloud with lidR?

This question is much more complex that it may appears. The LAS format First let's talk about the LAS format defined by the ASPRS. In a las file coordinates are stored as integers with a scale factor ...
JRR's user avatar
  • 9,444
6 votes

Determining bare earth DEM from unclassified LAS file?

This can be done with a pdal filter using either Simple Morphological Filter (SMRF) or Progressive Morphological Filter (PMF) algorithms. Quick pdal ground --cell_size=5 --extract input.laz out-...
matt wilkie's user avatar
  • 28.2k
6 votes

Coordinate transformation in LAStools?

A library that can read LAS data and links with proj.4 is the easiest way to project data and apply datum transformations. Both libLAS and PDAL support this linkage. Assuming the RSO Malaysia ...
Howard Butler's user avatar
6 votes
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Finding the coordinate system info from a LAS/LiDAR file with Python?

In this question: Getting the projection of a LAS file using liblas? Howard Butler (liblas developer) said that: To be honest, I think the easiest way [Getting the projection of a LAS file using ...
xunilk's user avatar
  • 30k
6 votes
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Choosing cell size in LAS Dataset to Raster Tool

Esri provides a guide on how to choose CELLSIZE, Assessing lidar coverage and sample density For sampling, choose CELLSIZE. You might think the average point spacing is a good cell size for the ...
whyzar's user avatar
  • 12.1k
6 votes

Cutting a hole out of a LAS file to omit that area?

PDAL supports a similar workflow, and it allows you to use any OGR-readable data source for the polygons. There is a tutorial on the PDAL website that describes how to do it. You can use Docker to ...
Howard Butler's user avatar
6 votes
Accepted

Erratic results from filters.normal in PDAL?

After all, it made sense. A flat plane can have 2 normals. In this case, the slight wobble of the rotating sensor made some points a little above and some points below the average plane. Hence the ...
tilt's user avatar
  • 3,269
6 votes
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Rescaling LAS file with lidR package in R?

lidR should not throw an error for that, at read time. It is invalid but not corrupted so it is readable. However writeLAS do throw an error. You have two solutions. The first one should be preferred ...
JRR's user avatar
  • 9,444
6 votes
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What is "degenerated ground point"?

If you are trying to create a 2.5D digital terrain model (a height field) from a point cloud then there might be two possible problems. Multiple points in the cloud at the same location don't add any ...
Spacedman's user avatar
  • 64.4k
6 votes
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Get eigenvalues of large point cloud using lidR

Your question is complex but luckily has an answer. For future readers I copy here (parts of) the answer I gave you on SO but that is lost in the sea in absence of appropriated tags on SO. The ...
JRR's user avatar
  • 9,444
5 votes

Shifting LiDAR point clouds that have been incorrectly georeferenced

I assume both point clouds have the same coordinate reference system. Then, if you know the actual tower location in the field, and also know its location in the point clouds; then, yes, one solution ...
Andre Silva's user avatar
  • 10.3k
5 votes

Use laspy to create las file from scratch without opening an existing las file first

The latest version of laspy will generate default file_sig = 'LASF', version_major = 1, version_minor = 2 and data_format_id = 0. However, the header offset and scale have to be specified. The ...
Ting On Chan's user avatar
5 votes

Converting LiDAR point cloud to 3D mesh

Be aware that .las and .obj are not the same type of data, in which the first is composed by points, and the second is a type of surface. So, even processing the point cloud to output a surface it ...
Andre Silva's user avatar
  • 10.3k
5 votes
Accepted

Visualizing LAS with matplotlib

This is a working solution with laspy: import numpy as np import laspy from mpl_toolkits.mplot3d import Axes3D import matplotlib.pyplot as plt # reading las file and copy points input_las = laspy....
zwnk's user avatar
  • 390
5 votes

Extracting projection from each LAS file in directory using ArcPy?

Laspy isn't going to give you convenient access to the SRS in a form you can easily consume. LAS files can have either WKT or GeoTIFF keys as the coordinate system description. For consumption in Esri ...
Howard Butler's user avatar
5 votes
Accepted

Unusual polygon shapes when using tree_hulls?

You found why there is no lastrees methods available for a LAScatalog yet in lidR. You did not consider the continuity of the tree IDs. In each chunk the trees are labeled from 1 to n. So in chunk 1 ...
JRR's user avatar
  • 9,444
5 votes
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Lasclip produces overlap with non-overlapping shapefiles

You are right. When reading a collection of files only the header is read and thus what you are seeing is the bounding box of the files. But the actual point cloud is what you are expecting. ...
JRR's user avatar
  • 9,444
5 votes

PDAL filters reprojection is not changing Z values

UTM 15N EPSG:32615 doesn't technically have a vertical datum, so to do a vertical transformation a vertical datum has to be specified. I changed the input SRS to --filters.reprojection.in_srs="...
TJR's user avatar
  • 1,612
4 votes

Lightweight python modules to convert LAS data formats to text formats?

What about PDAL? There is a Python package here - https://pypi.python.org/pypi/PDAL/1.2.0. Here is an example from the command line documentation: pdal translate input.las output.txt
Brent Edwards's user avatar
4 votes

Classifying raw LAS data as bare earth in ArcGIS for Desktop?

In ArcMap 10.4, there is the ClassifyLASGround tool, from the 3D Analyst toolbox. According to ESRI this tool: Classifies ground points in lidar data. Only the last return of LAS points with class ...
Andre Silva's user avatar
  • 10.3k
4 votes
Accepted

Get Z value from point in LAS Dataset using ArcObjects

This works at 10.2.2. It uses an envelope (constructed around a mouse-click point) to locate the LAS points. (I have it set as a small square based on map units for demo purposes, but something based ...
Dan Jurgella's user avatar
  • 2,378

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