Questions tagged [las]

An industry-standard binary file format that maintains information related to lidar data.

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2
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1answer
46 views

Georeference a LAS file with txt2las using a Geomedia coordinate system file (.csf)

I need to transform a file in a .csv file into a LAS file. I have a LiDAR data folder, in this folder I have these files: A .csv file that contains the the point data Some metadata files (schema, ...
4
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1answer
63 views

Lasclip produces overlap with non-overlapping shapefiles

Using a set of non-overlapping polygons (sf object) to clip a LAScatalog or LAS object creates an overlapping set of LAS files. I think the overlap is due to the use of the bounding box of the shapes ...
3
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1answer
67 views

Rescaling and reoffsetting a point cloud with lidR?

I'm trying to analyse a a 3 x 3 metres scan derived from terrestrial photogrammetry (i.e. local coordinates, with 0,0 in the centre of the point cloud) to obtain a DSM. Importing the file in lidR, I ...
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0answers
23 views

Extended Public Header Block + Point Data Records in LAS 1.4 Point Format Number 6 File

I've received a couple of LAS 1.4 PDF# 6 files with extended Public Header Block Records + Point Data Records. I noticed in the example “upgraded” LAS 1.4 file in the URL below, there were extended ...
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1answer
24 views

LAS Point Statistics as Raster in ArcGIS Pro fails to write raster

In the past I was able to use the ArcGIS tool LAS Point Statistics as Raster, but it is failing to work in ArcGIS Pro 2.2 or ArcGIS 10.7 on Windows 10. After creating an LAS dataset, issuing the ...
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0answers
28 views

Reproject LiDAR from Lat/Long to NAD83 with LAStools not working correctly

I'm trying to reproject a NOAA las file from Lat/Long to State Plane NAD83 using las2las. When I unpack the laz file as an las without specifying input or output coordinates it comes into GIS in the ...
2
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1answer
33 views

Intensity Range Correction - How to choose a power value?

I'm using lasrangecorrection from the lidR package to correct my Intensity values for effects of distance from sensor to target. I'm wondering how to best choose the f parameter (exponent for ratio of ...
2
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1answer
48 views

LiDAR: Seeking information about “Return Values”

I do not fully understand LiDAR Return Values, as opposed to Class Codes. Both Arc and LAStools have options for selecting returns based these "values". For example, here is the Arc 10.7.1 Make LAS ...
1
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1answer
29 views

Selection of Standard Range for LiDAR Intensity Range Correction

When correcting LiDAR intensity values for the effects of range (distance from sensor to target) many methods, including the one supplied by the lidR package (https://rdrr.io/cran/lidR/man/...
2
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1answer
55 views

Split LAS data from multi-beam sensors

I'm working with 4 different las datasets, each of which are produced by multi-beam sensors (Leica ALS70-HP and Riegl LMS 1560). In 2 of the datasets (Examples A, and C) the UserData field seems to ...
1
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1answer
45 views

lidR Range Correction Errors

I'm trying to use lidR to range correct the intensity values in my point cloud. I'm running into some trouble with running lasrangecorrection due to producing an unrealistic range value. The mean ...
1
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1answer
68 views

LAS file bounding box is oversized after using lasnoise?

I have a few .las files that I am trying to use further. They have some far away noise points that I removed using LAStools lasnoise. It seems like the noise points are removed, but the bounding box ...
2
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1answer
46 views

Extract the filename from a chunk when processing a LAScatalog

I'm using the R packages lidR and TreeLS to process lidar data and I made a function that takes in a single LAS file and splits out a shapefile, it looks like this: lasfile = 'tile_1.las' las = ...
3
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1answer
47 views

Directional pattern in normalized LiDAR point cloud

I have used the lidR package (https://github.com/Jean-Romain/lidR) to produce a normalized point cloud. I then filter out the points tagged with the overlap bit using: opt_filter(ctg) <- "-...
2
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1answer
33 views

Comprehensive list of filter string options in readLAS

Is there a comprehensive list of string based filters that the lidR package supports in readLAS()? For example: filter = "-drop_z_below 0" filter = "-drop_withheld" I know there are many more ...
2
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1answer
37 views

How do I correctly remove the buffer using catalog_apply?

I'm applying lasnormalize with catalog_apply in lidR with opt_chunk_buffer set to 20 metres. I do not remove the buffer explicitly and the normalized las files, which are returned, include the hits ...
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0answers
23 views

Clipping LAScatalog with polygon in R

I tried variants for lasclip with R: lasclip las file with single polygon and lasclip LAScatalog with the same single las file inside the catalog. Both times I used the same single clipper polygon....
2
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1answer
107 views

Converting las data into xyz with QGIS

I want to use QGIS 3.4.13 to convert las files into xyz-text files. So far I installed the LAStools Toolbox in QGIS and I think I can use the las2txt tool for the conversion. However I get the error ...
2
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0answers
49 views

Extract point cloud data from shapefile with Python

I am trying to plot profiles from LAS data. So my first step is to extract the data using a shapefile. I found this piece of code on the laspy website and thought I could use it to do this : def ...
2
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0answers
50 views

lidR:::catalog_laxindex() - “largest interval gap increased to…” logged

Often when running lidR:::catalog_laxindex() on a catalog of tiles I'm seeing the following log messages: largest interval gap increased to 1554 largest interval gap increased to 3802 largest ...
2
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1answer
55 views

If converting .xyz to .las using e.g. laspy, then how to specify offset and scale?

I have data from Lidar in .xyz format. I read that it could be beneficial to convert it to .las. So that one can use e.g. laspy -library. For example (code copied from an example): import laspy ...
2
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0answers
38 views

Clarification on LAS Overlap Flag

I am somewhat confused on the meaning of the Overlap flag which is present in las spec 1.4. The ASPRS LAS Version 1.4 Spec states: New to LAS 1.4 is the fourth flag, OVERLAP. It is frequently ...
4
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2answers
149 views

Overlapping LAS tiles

I have a las catalog with overlapping tiles. LidR warns me of this, and I'm wondering how concerned I should be. The tiles are in las version 1.2 with point record format 1. None of the points are ...
5
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1answer
152 views

Unusual polygon shapes when using tree_hulls?

The following script uses lidR to segment trees and output tree hulls (i.e. polygons representing individual tree canopies). Input data are a directory of laz files and a catalog is used to manage the ...
2
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1answer
32 views

lidR - Bad scan angle

When reading a las file I'm getting the following error: > readLAS("/tmp/chunk89/u_6300085100_2015.las") Error: Invalid data: ScanAngle greater than -180 degrees. In addition: Warning messages: 1: ...
2
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1answer
62 views

lidR - lasnormalize error handling

When normalizing a lasCatalog, the processing stops early with the following error: An error occurred when processing the chunk 22. Try to load this chunk with: chunk <- readRDS("/tmp/RtmpdcuTUO/...
2
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1answer
78 views

Find optimal chunk size using opt_chunk_size() in lidR catalog?

Is there a way to find the optimal chunk size using opt_chunk_size() when using a lidR catalog? I seem to always randomly choose integer values until the program quits throwing errors at me. For ...
2
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1answer
46 views

LASCatalog - Inconsistent number of VLR

I have a LASCatalog that is producing some funky outputs so I ran a lascheck() on it. The output tells me that catalog has inconsistent number of VLR, but what does this mean? I know that variable ...
0
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1answer
57 views

Getting *.las file data into SAGA las processing tools?

How do I get .las files into SAGA las processing tools? Do I have to convert *.las data to *.sprm format first? If so, how?
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0answers
39 views

ArcGIS Pro tool is failing. “Set LAS Class Codes Using Features”

I'm using ArcGIS Pro and I have a nice LAS Dataset. It came to me with the points already classified. The classifications are off, many buildings are classified as vegetation, for example. I'm trying ...
2
votes
1answer
54 views

Ignoring buffer files in processing

I'm wondering if it is possible to include some las files in a LAScatalog only for the purpose of providing a buffer to other las files. For example, I may only want to normalize 2 las files and use ...
5
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1answer
60 views

Reading remote LASCatalog

Would it be possible to read in a LASCatalog from a URL or vector of URLs? It is not possible with the standard function, readLASCatalog(). The benefit would be that you don't need to download all ...
2
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1answer
151 views

Extracting (big) rocks from LiDAR data

I have a .las file and want to show the outline of the big rocks located in this area. So far I have done the following: Obtain a ground model from the .las file including the rocks. Calculate ...
0
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1answer
71 views

Point cloud - Why don't all the points show up in AGOL or ArcGIS Pro?

Whenever I upload a LAS file in ArcGIS Pro, not all the points are shown. And there are even less points when I upload it to AGOL. Is there a maximum of points ArcGIS Pro and AGOL can show ? If yes,...
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0answers
35 views

Showing all points of point cloud layer using ArcGIS Pro

I have a point cloud file of some trees. I first convert this to a LAS using some converter tool. I then open this LAS file in ArcGIS Pro and somehow it doesn't show all points there is. Even if I set ...
3
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1answer
90 views

What is “degenerated ground point”?

When processing a dtm from lidR::grid_terrain() I'm seeing several warnings that say: There were 4 degenerated ground points. Some X Y Z coordinates were repeated. They were removed. What is a ...
2
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1answer
108 views

Difference between classification methods with Laspy

I need to add classification to create a LAS file. I used the code below but it was miss-classified. Is there any problem with the code? And what is the difference between: out.file classification ...
2
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0answers
252 views

Converting from .las to .ply and vice versa in Python? [closed]

I am trying to convert a .las/.laz file into .ply file, read the .ply file, do some processing on it and then convert it back to .las/.laz file. Is there any Python implementation for this? For ...
6
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1answer
408 views

Rescaling LAS file with lidR package in R? [duplicate]

I am trying to process a large .las file received, which appears to have been scaled in non-standard ways for some reason (likely data transfer portability). The scales between x, y, z are different ...
2
votes
2answers
841 views

Reading LAZ file in Python directly?

I am able to read .las file in Python using laspy in Windows as below: las_filename = 'abc.las' inFile = laspy.file.File(las_filename, mode='r') But when I put a .laz file in this code, I get the ...
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0answers
56 views

Adding RGB values from a .txt file to a .las file using laspy

I have a text file that has XYZ and RGB values in it. To convert it to .las format i use lfile = laspy.file.File(r"D:\las\tolas.las", mode='w',header=LasHeader(x_scale=0.01,y_scale=0.01,z_scale=0.01))...
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2answers
158 views

Seeking free public LIDAR data of road in LAS format?

I am currently working on LiDAR point cloud road marking extraction. Please help me to get relevant public dataset in LAS format? Sample data is as shown in the image below: Data without original ...
1
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1answer
39 views

Converting LAS Dataset into a point feature class with x-y-z in TOC?

How can I convert a LAS data set (displayed as LAS point elevation in ArcGIS 10.5) into a point feature class with x-y-z information attached to it (or stored in the attribute table)? ArcGIS has the ...
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0answers
121 views

Extract/Clip LAS (LiDAR lasd) based on shapefile, using ArcGIS Pro and ArcMap 10.6

I have a few large LAS files which span a big area. I have created an .lasd dataset in ArcGIS Pro and ArcMap 10.6. I want to use a shapefile to define the extent of the LAS file, and extract/filter ...
1
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2answers
51 views

Further compression of LiDAR data besides LASZip

I am looking for a way to compress files other than LASZip that may make the files a bit more smaller, is there an efficient way to do this? Would zipping up a LAZ file further compress the file? Or ...
2
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2answers
91 views

writeLAS writes corrupted file: 'end-of-file' after 10468 of 10474 points

I am seeing strange write behavior with lidR. The outputs from lidR are compressed to fall on a single line. I vaguely recall discussing this with JR before, but cannot recall a solution. #ok las0=...
0
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0answers
83 views

LAS to PCD conversion by preserving original coordinates?

I need to convert files from LAS format into PCD format. I tried PDAL, but it doesn't preserve original coordinates in output file. pdal translate input.las output.pcd It changes coordinates from ...
4
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0answers
100 views

Maintaining extra data for .laz for use in R and Python?

I am working on releasing a benchmark dataset for trees in RGB + Lidar and I'd like the format to match the most common use cases and packages. I had been intending on proving a tree index using the ...
4
votes
1answer
292 views

How to use lastrees on a catalog with a function requiring a CHM raster?

I'm still fairly new to using LiDAR data and R, so please let me know if this isn't clear. I am using the lidR package to segment individual trees over a large landscape. I have been using the ...
0
votes
1answer
293 views

Converting .LAS to .PCD file using CloudCompare

I want to convert a LAS file to PCD format using CloudCompare software. How I can do that?

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