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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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Convert a RGB LiDAR raster image to a greyscale height map in QGIS [closed]

I am fairly new to the world of GIS and also using QGIS. I normally use a greyscale height map to create a 3D terrain in external 3D software. I have a location where I only have access to a RGB ...
Karen Gazzard's user avatar
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Open platform to visualised bathymetry LiDAR [closed]

I have point cloud data that I want to visualise on an open platform, which I can extend tools upon to investigate further. I was wondering if any offer a visualisation like below, where the ...
guest_231213's user avatar
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Apply affine transformation to LiDAR .las file

I'am currently working on a project that use a Local Coordinate system, and I need to reproject the file to UTM WGS84, to be able to load it to qgis. I have the formula and values to reproject the ...
José Bustamante's user avatar
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Aligning separate datasets with different CRS in QGIS for the purposes of terrain modelling

I would like to develop a 3D model of a site located in Vermont, USA. I will be using the state's LiDAR dataset which I am pretty comfortable with. However, I need to coordinate this topographical ...
Carlos Guzman's user avatar
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Combine DTM with hillshade in QGIS

I'm wondering if it is possible to combine a LiDAR generated DTM on a 1m Scale with a Hillshade DTM on a 0,25m Scale to improve the level of detail of the LiDAR DTM. If possible how can this be done ...
Alexander Kutschera's user avatar
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25 views

LiDAR point cloud has no classfications [laspy], trying to classify and filter ground points

I have a .las file of data collected on a road, and I would like to get only the ground and points 'below' ground (potholes, other indentations, for example). However, when I load the data, it seems ...
mimzj's user avatar
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Deriving contours from .las files

I am trying to derive different contour lines from my LiDAR data. I am running in to an interesting error though (see attached picture). Any idea on how to rectify this? Smoothing?
GJW's user avatar
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1 vote
1 answer
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Point Cloud Processing Tools on MacOS

I am trying to access the native Point Cloud Processing tools, developed by Lutra Conslting and added to QGIS 3.32 (https://www.lutraconsulting.co.uk/blog/2023/05/30/pointcloud-qgis-processing/). I ...
SamH's user avatar
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2 answers
86 views

Visualizing LiDAR image

I am new to QGIS and I am using QGIS 3.22 on a Windows 10 OS. After importing the .laz file into QGIS (with the "Add point cloud" command) I can only seea square whose boundaries are made of ...
Antonio's user avatar
2 votes
1 answer
93 views

Writing COPC is not supported - Laspy

I have a simple code import laspy las = laspy.read('data/segmented.las') old_class = las.classification las.classification = new_class las.write('data/segmented_5.las') But this gives an error ...
Hrushi's user avatar
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QGIS LAS Elevation profile outputs - include instensity, return, etc and access via python

When I run an elevation profile in the current Dev of QGIS I get the graph as expected but if I save to gpkg, it creates a point dataset to which I can then add the x and y but how do I get the ...
GeorgeC's user avatar
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1 vote
1 answer
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LiDAR DTM slope slope analysis with a twist. Calculate elevation changes of at least 10 feet within horizontal distance of 25 feet

I have raster DTM image of LiDAR data, mapped to Washington state plane north (US survey feet), where each pixel represents an elevation value in feet. Generating a "slope map" which shows ...
Nick's user avatar
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1 vote
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How to augment LiDAR/DSM data from 3d models

For a viewshed analysis in QGIS 3.34, the I have LiDAR/DSM geotif files available. I want to modify/augment the DMS layer by adding the height information from 3d models of specific buildings. This ...
Wolfgang Haak's user avatar
4 votes
1 answer
140 views

Automate LiDAR DEM feature extraction using R

Can the delineation of bowl-like depressional landforms be automated from a LiDAR TIFF using R? library(terra) fu <-system.file("path/to/the/data/provided/below.tif", package=&...
Eron Raines's user avatar
2 votes
0 answers
87 views

Doing simple manual classification of LAS using QGIS

Are there any basic tools for lidar classification in QGIS? Id like to do simple function like reclassing single points, classing points inside a fence or above a line. something similar to the basic ...
LidarBeaver's user avatar
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Bad quality ground LiDAR cloud points

I got this point cloud using slam100 laser scanner, but seems to have an bad quality, someone said its all noisy, how could I fix that?
Gabriel's user avatar
4 votes
4 answers
459 views

How can I find the Point Cloud Tools in QGIS 3.34 Mac Version?

I just downloaded the QGIS Latest Release Version 3.34 (Prizren) for Mac to try the new Point Cloud tools, that should be natively available according to this post: https://www.lutraconsulting.co.uk/...
Enzo Baldini's user avatar
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DEM from LiDAR using cloud compare

I am working on overseeing a comprehensive flood analysis project in Bardonecchia, Turin, Italy, post the August 2023 flood event. I have been handed over the LiDAR file .las in which flood occurs. I ...
Ameer Turab's user avatar
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Exporting .LAS file after using v.lidar.correction

Question I want to use the GRASS GIS LIDAR modules (v.lidar.edgedetection, v.lidar.growing, and v.lidar.correction) to classify points for LAS files. I'm very new to working with databases, and the ...
mozmoz3737's user avatar
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Trouble reading LAZ downloaded from NOAA LiDAR database

I am attempting to download the raw point cloud of a LiDAR acquisition from NOAA's Office of Coastal Management's LiDAR database using R. The data download with out error, but when I read in the laz ...
Sean McKenzie's user avatar
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1 answer
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How to calculate voxel metrics for a LAScatalog using lidR?

I'm trying to calculate metrics for a LAScatalog with the voxel_metrics function. This is the code I used: library(lidR) ctg <- readLAScatalog("laspath") voxel_metrics(ctg, ~mean(Z), 4) ...
user232510's user avatar
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1 answer
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lidR producing error "$ operator not definied for this S4 class" when trying to apply function to lascatalog using catalog_apply

I am trying to write a function to calculate specific metrics which I can write to a data frame and then a .csv file to write 'reports' on each las file in a directory. I have tried the following code:...
Dr-JH-o'clock's user avatar
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1 answer
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curl failure using pdal.Reader.ept

I am trying to use Reader.ept to access data via a URL. The URL works fine and I can visualize the number of points in the polygon. However when I try to use a pipeline to access the points and ...
ike's user avatar
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2 votes
2 answers
94 views

Filter just the last return from a point cloud

At 3.32.3, the Processing Toolbox > Point cloud extraction > Filter tool does not include the ability to select only the last return in its list of filter expressions. This functionality is ...
Stu Smith's user avatar
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Iterating through las directory using lidR in R results in not finding file or not recognising file as .las

I am trying to produce a script which has functions that can produce a list of statistics and writes them to data.frame, which can in turn be written to a csv file if needed. This would be to check ...
Dr-JH-o'clock's user avatar
1 vote
1 answer
194 views

PDAL mesh pipeline producing poor mesh results and losing precision

Intro: What I want to do is: read in a las file crop the las around a specific point in space (probably using a radius) generate a mesh with cropped points using poisson The PDAL pipeline below ...
Drew Scatterday's user avatar
0 votes
1 answer
49 views

Plotting real (normalized) las values on dtm

I am trying to plot a las where I filtered objects, that have a first and a last return simultaneously (objects in the las file), onto a created dtm of the same las. I am able to produce a good result....
utz's user avatar
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101 views

How to derive first return points from a raw LAS data file

I have a raw (never classified) las dataset derived from UAV that I am attempting to obtain a DEM, DSM, and eventually CHM from. I have successfully been able to classify ground points and vegetation ...
greg684's user avatar
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How to classify points in LAStools using shapefiles as reference

I am new to LAStools, and mostly use MicroStation/Terra for classifications, except MS is a resource heavy at times so can be slow and can crash. The macro we run uses shapefiles as a reference, and ...
Warrick Allen's user avatar
4 votes
1 answer
147 views

Finding/highlighting significant elevation change

I am quite new to QGIS, so pardon if I use the wrong terminology etc. I am scouting terrain to find new bouldering/climbing locations. My goal is to find significant elevation differences and ...
exksalted's user avatar
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0 answers
38 views

How to have a good rendering with mdenoise - DTM LiDAR denoising

I'm trying to generate a clean slope map from a LiDAR DTM. Due to LiDAR high resolution, the slope map is full of noise. So to do this, I use mdenoise library. It works quite well but it generates ...
Tim's user avatar
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1 vote
1 answer
122 views

Removing trees from classified LiDAR based on polygon layer

I need to adjust the areas in a .las file where the trees and shrubs were cut last year. There are basically 5 classes, with one class ("20") for taller vegetation. Is there a simple ...
Bernd V.'s user avatar
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1 answer
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PDAL readers.ept fails to save LAS file

I am attempting to access the USGS 3DEP LiDAR Point Clouds - Registry of Open Data on AWS via the EPT PDAL reader in Python. I normally work with Python notation, so my code looks like this: extent = ...
Vicent-Ribas's user avatar
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1 answer
583 views

PDAL merging multiple LAZ files from folder in Python

I am attempting to merge multiple laz files stored in a specific directory. I have seen in the PDAL documentation that PDAL doesn’t handle matching multiple file inputs except for glob handling for ...
Vincent's user avatar
0 votes
1 answer
162 views

Cannot join LAS file In QGIS with Whitebox Tools

I have 9 .las files that I am trying to join into a single .las file in QGis. I have been using Whitebox tools plugin in QGis and when I try to select all the files and assign an output file if get ...
proffarnsworth's user avatar
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0 answers
87 views

Extract complex roofshapes from LiDAR

I've been using the 3D Basemaps Solution on the ESRI Solutions page (I no longer see it listed) for a little over a year now with ArcGIS Pro with mixed but improving results to create scenery for use ...
tarnis's user avatar
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0 answers
177 views

Matterport E57 file

What CLI tools can I used to convert e57 to pcd/obj files? I am trying to show my users the 3d representation of a scanned building taken by a lidar camera on a map, I think version 3 camera, I don't ...
Nick Licata's user avatar
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0 answers
96 views

QGIS 3.28 - 3.32 - Can not open .LAS-file format

I have multiple datasets of LAS-files, which I can not open in QGIS. I get an error stating LAYER is not supported or something like that. I do, however, have files with an .ept extension in JSON-...
Bob's user avatar
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0 votes
0 answers
85 views

Clipping LiDAR Data to Map Data w/ LAStools bounding boxes have no overlap

I am trying to clip a series of LiDAR .las files with the lasclip64 tool in LAStools. The area I am trying to clip is Prospect Park in Brooklyn, NY. I have retrieved the .shp file for this area from ...
proffarnsworth's user avatar
5 votes
1 answer
256 views

Computing grid cell statistics using LiDAR point cloud in QGIS

I have a LIDAR data .laz file of a DEM and a cell grid vector file. I want to compute grid cell statistics, like mean and variance using the LiDAR data. How can I do this in QGIS?
user1889930's user avatar
1 vote
0 answers
67 views

ArcPy IDW interpolation with LiDAR point cloud data

There are several questions such as 1, 2 etc on interpolation, but, when I implement the same procedure to calculate digital terrain model from point cloud I get an error: las_path = r"C:\Users\...
User2010's user avatar
  • 103
3 votes
1 answer
155 views

Classify vegetation by height

Trying to further classify a las catalog that already has buildings, bridges, noise and ground classified. I want to break the unassigned points into vegetation classes by height but can't get it to ...
pseudotsuga's user avatar
0 votes
1 answer
452 views

Downsample pointclouds from USGS (.LAZ) files in Python

I am trying to process pointclouds from USGS for a project and I am having a hard time working with the data (.LAZ files) because they are very large. They have around 36 million points. I tried ...
Tarun Srinivasan's user avatar
1 vote
0 answers
226 views

How to clip USGS LiDAR data and polygon files

Am kind of new to the whole Geo Info systems, I am trying to clip USGS lidar data which is (.laz) format using polygons in a (.shp) file. I am using Python 3.10: with packages laspy, geopandas. I use ...
Tarun Srinivasan's user avatar
1 vote
0 answers
178 views

LiDAR data processing - Which is best Python or R? [closed]

I have started working with LiDAR data processing recently. I looked up for libraries to work with LiDAR in Python and R. I would like to know which one has better libraries and extensive ...
Subha's user avatar
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0 votes
1 answer
336 views

Filtering LiDAR points by elevation/height

I am trying to prepare training data for a deep learning model. The objective is to be able to identify trees in an urban area. Properly classifying the points in my training data would be a lot ...
amcameron's user avatar
0 votes
0 answers
93 views

Esri deep learning model is not particularly effective

I am using Esri's tree classification deep learning model, in conjunction with the Classify Point Cloud Using Trained Model tool, to classify LiDAR point cloud data in an effort to develop a tree ...
amcameron's user avatar
1 vote
1 answer
619 views

LiDAR LAS to DEM in QGIS 3.22 without LAStools

I'm using Ubuntu Linux and have installed QGIS 3.22 which has native support for LAS files. I think that LAStools is for MS Windows only? I can load the LAS data and see a pretty image. Next, I want ...
stweb's user avatar
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1 vote
0 answers
92 views

Write classification to raster for highest object in LiDAR point cloud

What we want to do is rasterize the classification value of the highest point (in the Z dimension) in every pixel. Basically we are trying to mimic optical imagery where whatever is on top is what is ...
fnands's user avatar
  • 26
1 vote
1 answer
82 views

Plotting CALIPSO data in R

I am trying to plot one subdataset of CALIPSO which is in hdf format using R. The data is totally new to me as it's LiDAR data. I am not able to understand how to plot a graph between backscatter ...
shravani banerjee's user avatar

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