Questions tagged [lidar]

LIDAR (Light Detection and Ranging or Laser Imaging, Detection and Ranging) is an active optical remote sensing technology that measures properties of scattered light to find range and/or other information of a distant target.

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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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41 views

Change LIDAR classification of points inside polygons

I'm trying to create a pdal pipeline to adjust the classification values for all points inside polygons, but I can't seem to get it to work. The filters.range works correctly because the output file ...
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1answer
54 views

LiDAR Data captured, unsure what units or format this time field is in?

I haven't been able to figure out or find out from searching around what units or format this time field is in my LiDAR data that was collected?
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2answers
67 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 ...
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1answer
47 views

Creating rasters from LiDAR using parameters other than elevation, intensity or class?

There are a number of tools out there that can create a raster from a LiDAR point cloud by interpolating elevation, intensity or class values, but these tools generally limit you to interpolating ...
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1answer
25 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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12answers
27k views

Working with LiDAR data using other than Esri software?

I will be working with LiDAR data soon and I am wondering what the alternatives to using Esri software to do this are, including open source solutions?
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1answer
120 views

Masking LiDAR points to create DEM in ArcGIS Pro with ArcPy?

I have an irregular LiDAR point cloud dataset, so when I try to create a DEM or DSM, the points are connected across the irregular edges of the LiDAR point cloud. I thought that creating a mask ...
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2answers
218 views

Rasterizing ungridded XYZ (LiDAR) files? [closed]

I have a large set of ungridded xyz text files (LiDAR point cloud) and want to export them to any raster format (tiff, asc, gridded xyz...) for further GIS processing. The source: https://www....
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2answers
27 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 ...
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2answers
402 views

Adding RGB values to Laspy synthetic point generation?

What is the correct way to add RGB values to points made from scratch? Laspy is working great for me so far. I want to add RGB values to synthetic points that I've generated. I am using 2 numpy ...
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1answer
1k views

Merging multiple LiDAR (.las) files?

I downloaded about 9 LiDAR scenes from USGS and I want to use ArcGIS to merge them so that I can carry out tasks on them together as opposed to one by one.
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1answer
35 views

lidR: no slot of name “header” for this object of class “LAScatalog” [duplicate]

edit: This question does share an answer with an existing question, and the problem is the same: lastrees() does not work on LAScatalogs. However, I'm going to leave this question up, because I think ...
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4answers
4k views

Creating DSM and DTM from a LAS using a freeware solution

Is it possible to export a surface and terrain model files from an aerial, LiDAR point cloud (LAS) set? I am using SAGA GIS for very basic operations, but I couldn't find this option (and I have a ...
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1answer
1k views

How to install PDAL in Windows?

I want to import .las files to PostGIS. As I found out I can do it by using PDAL. However, I cannot find the right way to install it in Windows. I downloaded a folder from here https://www.pdal.io/...
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Combining/getting elevations from .asc files or .tiff with x and y locations [closed]

I am new to R and still getting to know the environment. I am doing a project in animal movement. I have x and y locations (plus IDs, dates, hours) in an Excel table, converted into .csv as well. I ...
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2answers
47 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=...
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1answer
33 views

How does a LiDAR placed on a moving vehicle map the distances?

Please correct me if I'm wrong but LiDAR device shoots out multiple laser rays and maps the surroundings based on the time taken by the rays to reflect. But if the LiDAR is placed on a moving vehicle (...
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1answer
241 views

Visualizing LAS with matplotlib

I'm trying to create a 3D scatterplot using an las file that contains xyz and return values. I want to keep all returns but would like to subset the cloud. I've learned how to subset using laspy so no ...
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1answer
51 views

Configuring lidR catalog to overwrite raster output (with different extension)?

I have a small issue with configuring the lidR package for parametrizing the extracted raster files with grid_metrics() function. My question is how to set in the catalog options that: be able to ...
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1answer
31 views

Using lidR to count number of pulse returns at different intervals?

I am trying to get the number of pulse at different height interval. I have used the lidR package to do this before with the code below but it seems that recent update in the package breaks my code. ...
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1answer
69 views

Why a laz file warns: 'return number' greater than 'number of returns' in R?

Reading a laz file with the lidR package in R I have the following warning. What does it means? las = readLAS("chmp15.laz", filter = "-drop_z_below 0") #> Warning message: #> Invalid data: 8895 ...
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1answer
137 views

How to assign (or project) CRS to LiDAR file in lidR?

Can someone enlighten me if there is a difference between initializing a CRS object using the EPSG code versus just the +proj string read from a shapefile? Consider the following objects: A ...
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1answer
112 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 ...
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2answers
97 views

Filtering above ground LiDAR points using a catalog in lidR?

I am analyzing LiDAR data collected two separate years- 2007 and 2015. My analysis is centered around changes in vegetation during this time period. The ultimate goal is to thin the data from the 2015 ...
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38 views

Creating DEM raster from ASCII .xyzi LiDAR [duplicate]

I was passed along some LiDAR data that is in .xyzi ASCII format. I am having trouble figuring out a way to build a TIN or DEM from this data. I brought it in using "ASCII 3D to feature", and ...
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Stacking lidar-derived height raster as ancillary data for segmentation in ENVI?

I get a a black and white image after following these steps. Does anyone know why I'm not getting a color aerial image beneath the mask? My setup consists of these steps: I mosaicked several NAIP ...
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4answers
916 views

How to filter LiDAR data by scan angle?

I am looking to filter LiDAR data (.las format) by scan angle specifications (e.g. keep all points < 15). From a basic Google search, it appears that the libLAS library has the ability to filter by ...
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1answer
57 views

lidR (rlas) writeLAS changes values from Classification attribute?

I have a point cloud with extra attributes: class : LAS (LASFˇ v1.4) point format : 6 memory : 2 Gb extent :7498400, 7499200, 5779500, 5780000 (xmin, xmax, ymin, ymax) coord. ref. ...
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1answer
40 views

Does lasfilterdecimate work when homogenizing by pulse?

In R lidR package, when I run lasfilterdecimate with the homogenize option excluding use_pulse = TRUE it works, but when I include use_pulse = TRUE, it does not work. For example, the code below ...
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1answer
57 views

Convert EPSG:2263 LiDAR data to EPSG:4326 to use with FSX

I have LiDAR (las) input files in EPSG:2263 (NAD83, NY state plane, feet_US) aquired from https://gis.ny.gov/elevation/ and want to convert those file to EPSG:4326 (WGS84) for use in MS Flight ...
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3answers
73 views

Problem with CRS metadata for UK Environment Agency LiDAR DSM tiles?

I have downloaded some LIDAR DSM composite tiles from https://environment.data.gov.uk/DefraDataDownload/?Mode=survey and opened them in QGIS 3.6 with project CRS set to OSGB 1936 (EPSG:27700). ...
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1answer
195 views

Tracking which LiDAR data tiles have been delivered?

My company works with LiDAR data for large electrical transmissions systems (thousands of miles in one project). We model the transmission lines and do analysis using CAD and GIS workflows. We break ...
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4answers
10k views

Creating DEM from LAS file without using LAStools?

I want to create a ground model from a *.las file. The LAStools are available in QGIS but limited in use (generation of black diagonal in result file), so I can't use this. In the GRASS tools I can ...
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7answers
35k views

Viewing LIDAR data (.las) in QGIS?

Is there an easy path to visualizing LIDAR data in QGIS? I have some USGS LIDAR data in .las format downloaded from http://lidar.cr.usgs.gov/. This means I have both the .las and metadata in .xml ...
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1answer
3k views

Installing LASzip in Ubuntu?

I have tried without any success to install LASzip¹ ² (paper by Isenburg about LASzip) on Ubuntu 16.04. The basic way gave me nothing relevant: ./configure && make & checkinstall which ...
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6answers
2k views

Ways to visualize multiple large LiDAR tiles?

I want to load approximately 10 large LiDAR tiles for analysis. I have tried using ArcScene but it appears there is a limit on how much data ArcScene can handle at one time. Each tile is 65-90MB in ...
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How to georeference point cloud data that was no spatial information?

I'm working on a project right now that the final goal is to compare two DTMs of a glacier surface from different years to visualize the change over time of the glacial surface. The first DTM was ...
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2answers
427 views

Failed to install Potree on Ubuntu 18.04 Bionic

I am trying to install Potree on my computer and I am stuck. I am following these instructions: $ sudo apt-get install python-software-properties git $ sudo apt-get install build-essential cmake g++ $...
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1answer
146 views

Setting GroundFilter parameters for low density point clouds?

I'd like to use the function GroundFilter on my dataset. However, the manual says that the default values of the parameters used by this function (g parameter, w parameter) are related to a high ...
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1answer
71 views

GridMetrics output does not align with base DTM?

I am trying to derive grid metrics from LiDAR (.las) file using FUSION's GridMetrics tool. My problem is that the output raster from GridMetrics does not align with the base DTM used to run the tool. ...
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1answer
43 views

lidR lasaddextrabytes does not update header

My lidR version is 2.0.2 I am trying to add an extrabyte about treeID that I get from raster (lasmergespatial with vector is super slow). I have a problem with saving that extrabyte to LAS file. I ...
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1answer
432 views

Unable to install FUSION in QGIS 3.2?

I'm unable to install FUSION in QGIS 3.2 on Ubuntu 16.04. Andre Silva on Creating DEM from LAS file without using LAStools? says to use the same procedure as LAStools (up to QGIS 2.18 version). I've ...
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1answer
697 views

LAStools plugin in QGIS: ''The system cannot find the path specified."

I'm attempting to convert LAS files to a multipoint file using QGIS methods. I've found some documentation that suggests that v3.2 and up has LAStools available as a plugin so I downloaded the latest ...
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3answers
608 views

How to delete duplicate LiDAR points?

How can I delete duplicate LiDAR points? I incorrectly read the same las twice and saved as a one file resulting in duplicate XY points. How should I delete these duplicate points?
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1answer
78 views

Clipping a catalog with lasclipCircle returns “no point found within region of interest”

I'm trying to clip a catalog using lidR (v2.0.1) package. I've tried with lasclipCircle and lasclip. It gives me the error: no point in ROI, but when I'm viewing the shapefile using mapview (I've ...
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1answer
109 views

Configuring lidR catalog to save files with same filename?

I'm trying to learn how to use the options of catalog() within the lidR package in R. I'd like to save directly the processed files, for example, using grid_terrain() function over a catalog and save ...
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1answer
261 views

Calculating shadow of trees with DEM in QGIS?

I have a DEM with a good precision (0,5 x 0,5 m/pix LiDAR) and I´m looking for the way to obtain a raster (or shapefile) with the shadow of the trees located in that place for a whole day (ideally ...
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0answers
96 views

Timestamp mismatch in the data recorded by Vlp16 with Ublox-M8T

Currently, I am working on Velodyne vlp16, for which I recently added UbloxEVK-M8T support. The setup is working fine but when I record the data from VeloView, the GPS timestamp is showing incorrect ...
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2answers
132 views

Removing noise from point cloud with lidR package

I have unclassified Terrestrial Laser Scanning (TLS) point cloud data which has some noise. Is there a function in the lidR package which can be used to remove noise?