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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34 views

Terracing / stepping artefacts after converting lidar DTM from float32 to uint16

I am a beginner QGIS user, using it to supplement other skill sets in 3D modelling and rendering. I am trying to use UK lidar data in Blender to render 3D topographic maps. For this to work correctly ...
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38 views

Using LiDAR-Derived DEM to Identify Aerial Sewer Lines

I am trying to come up with the best process for identifying aerial sewer lines (typically over streams) using the pipe inverts and a LiDAR-derived DEM. In other words, locate the lines where the Z ...
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1answer
86 views

Why is QGIS contour generating tool not working with my DEM tiff file?

First a note about previous data processing. My original data (from a LIDAR scan) is a text .asc file with the internal structure looking like this: 457758.77;110272.34;353.89 457758.77;110273.34;353....
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Install LiDAR packages in Debian Bullseye

I'm trying to work with las2las in my Debian Bullseye. I'm not able to install LIBLAS packages because it seems not available in Bullseye repo. So I start to compile by myself from here https://liblas....
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1answer
41 views

Determining pixel size based on LiDAR point cloud density

I have a point cloud with a density of 8 points/m². I would like to generate a digital elevation model (DEM) from it, but I don't know what resolution to set as the raster pixel. So I would like to ...
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2answers
85 views

GEDI on GEE: Mismatched type for band 'beam'

I am trying to find, clip and download some GEDI data from GEE and I'm getting a casting error. My simple code is: var GEDI = ee.ImageCollection('LARSE/GEDI/GEDI02_A_002_MONTHLY') .filter(ee....
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20 views

PDAL reprojection rendering unexpected results

I am using a program where a Digital Elevation Model is produced from LiDAR data. The code is written in python 3.8 using the PDAL 2.3.0 library. I have a requirement to update the reprojection from ...
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68 views

Using pdal filters.divider to split LAS into multiple xyz-files

I'm runnig a pdal pipeline to do some pointcloud processing and finally I want to write to multiple xyz-files using the filters.divider. It works as expected if writing to Las-files using type: writer....
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1answer
52 views

Projecting LAS to local coordinates using lastools

Is it possible to project LAS files using Open source tools eg. lastools if using a less common coordinatesystem like local swedish espg: 3008 as destination and espg: 3006 as source? I see 3008 is ...
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Merging LiDAR files using R [closed]

I am downloading LiDAR files (.laz) from https://apps.nationalmap.gov/downloader/#/. How can I merge multiple files together using R? Note that this related to Merging multiple LiDAR (.las) files ...
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1answer
163 views

Converting LAZ to LAS using laspy

I would like to convert .laz file to .las. I am using Python and I have installed laspy with lazrs extension. I tried in Pyscripter (v4.0) following solution (this solution was mentioned here: Reading ...
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2answers
31 views

Highest LiDAR point return per sq m?

I currently have at my disposal QGIS and Trimble Business Center. I am looking for semi-automated solution for extracting the single highest lidar point return per square meter. My area of interest is ...
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Convert lidar (.las/.laz) to .slpk using .NET

is there any way to convert the lidar file (.las/.laz) into ESRI .slpk format and publish results to Esri Portal using .NET programmatically? I know that it is possible by using ArcPro GUI or Python. ...
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1answer
38 views

How to get las Zref values after normalization in lidR?

I understand that normalize_height() in lidR creates a Zref attribute so that it can be unnormalized. While I can print Z for the normalized file, I cannot print Zref. Subsequently, when I apply ...
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28 views

What tools/methods are there for spatial autocorrelation with raster data in ArcMap?

I'm using high resolution LiDAR data to find patterns in canebrakes. My hypothesis is that cover (represented by point density per cell) will be more homogeneous between height strata in canebrakes ...
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1answer
30 views

LAS catalog not loading - Error in sp::SpatialPolygons

I am getting this error that I have never received before. I have tried loading data in the catalog format with multiple LiDAR files including the Megaplot.laz data built into the lidR package. ...
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1answer
18 views

How to filter all but last returns using lidR?

I am using the great lidR package and want to check all points classified as ground which are not the last returns. How would I do that? Something like this would this would be logic for me but its ...
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28 views

Change vertical unit in a LAS/Z file with PDAL

I am using pdal translate to filter and transform some lidar files. One issue we have are the vertical units. Sometimes they are correctly specified, sometimes they are not, and sometimes they are ...
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1answer
63 views

Can I create .las or .laz files from .hgt, .tiff, .gpx/kml or .asc files?

I have got into a golf simulator game and want to recreate my home course. Problem here is that the only import way for height information is a LAZ or LAS file. So I am looking for a way to work ...
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1answer
45 views

Custom contours on DEM [closed]

I've made a DEM using LIDAR, and I'd like to mark specified contours on it as polylines. Is there a way I can create custom contours for specific heights OD? I can use either QGIS or ArcGIS Pro to do ...
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44 views

Problem using lidR functions on Mac

I have been going through LiDAR processing tutorials for R Studio and was successfully able to get through this one by NEON about 4-5 months ago: https://www.neonscience.org/resources/learning-hub/...
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1answer
47 views

Fix point cloud lidR - normalize_height fails

I'm working on an airborne lidar survey of around a thousand tiles (500m * 500m) using LAScatalog with lidR. I firstly ran a las_check()... No issues reported: las_check(CTG_Bertrix) #> Checking ...
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1answer
36 views

Efficiently write lidar data to csv with data.table::fwrite

I have a lidar file (.las) that I ran through my R function: writelas2csv <- function(x,y) { lasinspatpt <- list(as.spatial(readLAS(x))) write.csv(lasinspatpt, y, row.names = T) } but as we ...
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1answer
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lidR: las_check deep = T failed while deep = F succeeds

I want to run some test on a LAScatalog object using las_check with lidR in R. The first run worked just fine (all flags were green) and when I tried to run the same las_check(ctg_bertrix, deep = T), ...
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2answers
79 views

LiDAR with treeID exported to csv

I have used the lidR package in R to run a point cloud segmentation of trees using the li2012 algorithm. I am interested in exporting my results to a csv file, but the methods I have tried did not ...
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1answer
57 views

Using leaf-off LiDAR for canopy density and canopy height

Could someone explain the drawbacks of using leaf-off LiDAR data to calculate canopy density and height? Is it acceptable to use this at all? I have read a few papers but I find it hard to make ...
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1answer
39 views

Using lidR to calculate the number of null voxels

I have a number of LAS files (750+). I am using the package lidR to extract different metrics. I am using the following function to calculate the number of voxels in each files that contain a LiDAR ...
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1answer
272 views

Append .las files using laspy

I am attempting to append .las files to another .las file using laspy. Basically, I have a collection of .las files that I need to merge into one large .las file (it's for input into a different ...
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1answer
28 views

Extract AOI from LAS Dataset into a single las file

I am looking for a way to take a polygon (AOI) and extract a .las file from an las dataset. Currently, when I use the tool Extract LAS, the output is multiple tiles. Is there a way to either a) get ...
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24 views

Fill in nodata LiDAR gaps with PDAL

I'd like to use the ground classification (2) for everything except areas missing ground at the specified resolution, and then fill in those empty areas with unclassified (or ideally water, then ...
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1answer
72 views

lidR classify powerlines features which are misclassified as noise

I am using NOAA LiDAR data to experiment with methods in lidR. I want to use the linear segment_shapes() function to locate powerlines, but some of powerlines are already classified as noise. Using ...
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54 views

LiDAR data is displaying in wrong position

I spent most of today, unsuccessfully, trying to understand a LiDAR dataset. The dataset is from the Texas Natural Resources Information System and is identified as the Buffalo Bayou elevation LiDAR ...
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1answer
110 views

Converting DEM raster (NetCDF file) into point cloud (LAS file) using Python

I would like to convert a DEM raster NetCDF file (*.nc) to point cloud LAS file (LAS/LAZ) using Python language. I have been doing the research but still don't have a result. I also have a look on ...
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1answer
49 views

Overlapping (duplicate) ALS tiles

Related to this question: Overlapping LAS tiles, but none of the answers explicitly addressed my issue. I have overlapping ALS tiles, but not from 'duplicate' files. The tiles overlap because of ...
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37 views

Using Forest Tools R Script in ArcGIS Pro

Has anyone figured out how to get the Forest Tool functions to work in ArcGIS Pro via R-Bridge? I've set up the bridge and tried to create a script in ArcGIS Pro to run canopy tools to identify ...
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2answers
153 views

How to read LAS header or read only some attributes of LAZ file with LAStools/C++

It takes lots of time when reading laz files when you iterate hundreds of laz file. But reading only the header can only takes less than 100 ms to read hundreds of las files. The same problems arises ...
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26 views

Quantitative Structural Modeling (QSM) using LiDAR data in R

I am fairly new to QSM modeling. I have come across softwares such as simpletree and simpleforest that can create a QSM. There is also a R package called aRchi that works with QSMs derived from these ...
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1answer
62 views

Smooth LiDAR TIFF Data

I have LiDAR data as a TIFF file. As expected, human-made structures such as buildings show up as high points. I would like to have just ground-level elevations. I believe that what I want to do is ...
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33 views

LAZ LiDAR displayed as long line in 3D

I downloaded some LiDAR data in .laz format. The problem is that when I try to display it (for example in CloudCompare) it is just a long line. I know that .laz is a compressed version, reading ...
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1answer
38 views

QGIS LiDAR derived contour to Garmin GPS

I have this neat little contour layer in QGIS Desktop 3.16.8 that I derived from LiDAR data. How can I send this as a vector map in my Garmin GPSMAP 64s? Those contour lines are 1m and so vector is ...
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75 views

PDAL: how to create valid glb?

I'm attempting to create a glb model from a cropped laz file, using Python. The glb file is created successfully, but any reader (Blender, ThreeJS, online gltf validator) returns errors like: Bad glTF:...
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46 views

How to reproject a .LAS file from WGS84 UTM 32N to CH1903/LV95

I have a large .las point cloud (around 11GB) generated from pix4d and I need to convert its coordinate system from EPSG:32632 to EPSG:2056. I was able to export it as a CSV file but I am not able to ...
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1answer
48 views

Calculating Leaf Area Density for different vegetation types based on height conditions

The LAD function in lidR is used to calculate the Leaf Area Density. This can be done as shown below. Now, how can I calculate LAD out of a LAS file for different vegetation types based on height ...
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1answer
59 views

Export classification LiDAR to raster

I'd like to export the LiDAR data according to their classification in a georeferenced raster format. Something that look like that: Here is the code that I tested to retrieve the classification: ...
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1answer
173 views

LiDAR 3D modeling using package rayshader and LAS file in R

The rayshader package in R allows beautiful 3D modeling in R. Now I was trying to first try and overlay a LAS file on top of a base-map which is a Rayshader array object. I was trying %>% to link ...
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31 views

Importing data hosted in ArcGIS into QGIS

I am trying to load the data from this site: https://catalogue.data.govt.nz/dataset/lidar-2012-2013-contours-coromandel1 into QGIS, but despite all the options, I can't seem to get any to work. I ...
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19 views

Point cloud data load time in ArcScene

I have noticed that ArcMap takes a lot of time to render point cloud data when compared to the load time for the same file in ArcScene. Why ArcScene is so much faster in loading LiDAR data?
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1answer
80 views

Canopy Relief Ratio (Grid Metrics) FUSION/LDV

According to the paper cited below, CRR tells us about the shape of trees and is defined as: Canopy Relief-Ratio (CRR) is a quantitative descriptor of the relative shape of the canopy from altimetry ...
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1answer
83 views

lidR delineate crown spatial polygon error

While using the delineate_crown function to delineate crowns, I get a spatial polygon error. How can this be fixed? # Bring in the ALS file TP1 = readLAS("~/Sample.las") # Then, normalize ...
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1answer
58 views

LiDAR file only has first point returns

I am working on a LiDAR ALS file (provided as vertical rectified and classified as ground and unclassfied) which only has single point returns, which is strange because up until now all the ALS files ...

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