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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20 views

Is there a way to project LiDAR data from a GCS to a state plane coordinate system?

I have LiDAR data that is in GCS NAD83. I have converted that LiDAR data into an LAS Dataset for use in ArcPro. I'm now trying to convert that LAS dataset into a raster and the tool keeps failing with ...
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62 views

Tree Segmentation using lidR

In rLiDAR, you can segment trees by using CHMs ASCIIs produced by Fusion. Can the same be done in lidR? I know in lidR you have to use the .laz file for tree segmentation: LASfile <- system.file(&...
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33 views

lidR: Save LAS files from a clip_roi list

I have clipped a point cloud with a shapefile containing multiple polygons, using clip_roi() function. The result is a list of LAS files. However, when I try to loop through the list and save each ...
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Assessing relative positional error in a DEM

I have a set of ground control points collected with a differential GPS and I am trying to assess the relative positional error (in contrast to absolute elevational error) in a DEM. I would like to ...
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24 views

How to use French LiDAR CSV data in QGIS

Following on from this Assign elevation data to GPX from LIDAR data Please could you help with another problem. I'm trying to use the LiDAR data from France ( http://ids.equipex-geosud.fr/web/guest/...
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18 views

3D information is lost when using “Regularize Building Footprint” in ArcGIS

Currently I am working on the extraction of building footprints using ArcGIS/ArcPy and Lastools. Using LasBoundary I extract all buildings from the lidar dataset and get the building outlines as 3D ...
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45 views

Is it possible to read a subset of points with the PDAL C++ api?

I am using the PDAL C++ API to read LAS/LAZ data. We're finding some of the tile files are very large (160M+ points), so I wish to take a sample of them. Although the point order in the tiles is ...
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32 views

readLAS error in rLiDAR - can only read from a binary connection

I am having las file read error while using the rLiDAR package in R. My code is as follows: LASfile <- system.file("C:/03_processing/Test_LAS/LASexample1.las") rLAS<-readLAS(LASfile,...
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How to respond to marginal height error when using LiDAR DTMs in ArcGIS

I am comparing DTMs of a river valley over time using LiDAR data from the DEFRA download website. The Environment Agency state that this data has a relative height error of +/- 5cm. The problem that I ...
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85 views

Why is normalize_height() function aborting in lidR?

I'm trying to run normalize_height() on 328 las files. Maybe or maybe not relevant: I'm not running using LAScatalog because I couldn't get that to run at all. Anyhow, I'm running using a parallelized ...
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34 views

LiDAR data for 3D use

What data type do I need to create a LiDAR 3D surface model? I have downloaded LiDAR/DSM data from Environment Agency, both as a WMS and as individual ASCII files, and it looks good but I want to view ...
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FUSION Microsoft visual runtime library C++ blank error

I am trying to run the DTM script on 73 laz files (each file >500 MB) and a big single ground filter.laz file > 1 GB that has 303239327 points. The laz files ran just fine with the ground filter ...
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Calculate average elevation value in LAS files in a specific area [closed]

I need to calculate the average elevation and its standard deviation of some buildings and parts of roads using LAS files. I want to be able to consider only the points that are within a polygon in a ...
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1answer
28 views

Export more than one object with catalog_apply

I am looking for advice on how to export more than one type of object when using catalog_apply() from the lidR package. For example, in the code below the custom function fn_bufferTile() computes a ...
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R giving LAS file read error

I am using the rLiDAR package to read some LAS files, but the readLAS function in rLiDAR is giving the following error: Error in readLAS("D:/LAS_Files/test_1.las", short = TRUE) : no ...
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1answer
59 views

Understanding DEM of difference results in ArcGIS Pro [closed]

I am looking at channel change in a river in the UK and am using three DTM rasters to observe change over time. One of the methods I am using is to simply minus one DTM from another. I have got the ...
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GroundFilter.bat creating a .lda file and a 1 KB laz file

I ran the GroudFilter.bat FUSION script to create a ground filter file, but the script is creating a .lda file with a 1 KB laz file. How can I make the GroundFilter.bat script to create a laz file. By ...
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Comparing two point clouds, one in WGS84 and the other in ECEF

I'm really a newbie and this task seems over my head. Suppose you have one cloud from LiDAR (a LAS file) with coordinates in WGS84 and another cloud, obtained from structure-from-motion, in ECEF. They ...
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LiDAR data denoising algorithm complexity

I want to remove outliers (noise) from LiDAR data. Currently I'm using the same algorithm as LAStools: The LAStools software version 171215 implements a straightforward outlier removal ...
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2answers
100 views

Individual tree segmentation workflow with lidR package

I am seeking advice on how to build a workflow for individual tree segmentation (ITS) processing with the lidR package using catalog objects. My current ITS workflow is parallel and leverages the ...
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22 views

las2dem, command not found in terminal

I am trying to use the command las2dem in terminal (Ubuntu) to create a DEM with various las files but I only want to conserve the points classified as Ground. I'm using this command: las2dem -i file....
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19 views

Removal of drainage channels (defined by steep slopes) from LiDAR DEMs

I have LiDAR DEM tiles (geoTIFF) that feature modern (19th century?) drainage channels but also remains of the pre-modern landscape. To perform further analysis of the latter, I want to remove the ...
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1answer
72 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 ...
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129 views

Assign elevation data to GPX from LIDAR data

I am totally new to this, so sorry for the basic question. I have some GPX files which have elevation data, but I am aiming for greater accuracy. Currently I have used OS benchmarks to correct the ...
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40 views

Elevation obtained from USGS DEM is different from Lidar elevation

For a project I'm working on I need to calculate height of objects for which I know their spatial 2D coordinates (e.g. buildings). I'm using Lidar data to extract the highest Z value for an object, ...
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24 views

Sensor frame to global frame transformation matrix

I am using Carla simulator in which all data is represented using various coordiantes. But for convenience i turn all data into standard cartesian frame(the simulated world is only a few sq.kilometers)...
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42 views

How do I get R to recognize a buffer around a las file?

I'm trying to clip from a catalog using a shapefile. The file is huge, so I've divided it into two (ctgw1 and ctgw2). The final radius should be 47 (the ctg is in feet) and I'm trying to set a buffer ...
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26 views

How does the runtime of Haralick texture generation scale with the number of bins/gray levels? (Orfeo)

I'm trying to generate some Haralick textures of various LiDAR-derived elevation models (digital height models and digital surface models). Because the height models (DHMs) have a lower bound of 0 and ...
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2answers
42 views

PDAL is mixing Lat and Lon when using tindex

I am trying to extract polygon representing the extent of my .LAS file. I am using tindex to do so. When importing the resulting file, it looks like longitude coordinates are set as latitude and vice ...
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1answer
82 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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Correcting offset between LiDAR datasets

I am analyzing multiple LiDAR datasets looking at the changes between pre-wildfire and post-wildfire topography. The datatsets are of the same general location. I did not acquire the datasets on my ...
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Convert point cloud dataset with RGB encoding to FBX format

Hope you all are doing good. I have a point cloud dataset with RGB encoding. I need to convert it to FBX format. Is there any way to convert it? Is there any option available? Looking forward to ...
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25 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
56 views

arcgis.learn show_batch() index error and lr_find() runtime error while using pointcnn for LiDAR segmentation

I am trying to segment vegetation from LiDAR point cloud using PointCNN on Jupyter notebook. But I am getting Index Error on running show_batch() and runtime error on running lr_find() while using ...
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What unit of measurement is rxwaveform from the GEDI L1B dataset in?

Rxwaveform is listed in GEDI's data level product L1B's data dictionary as "The corrected receive (RX) waveforms. Use rx_sample_count and rx_sample_start_index to identify the location of each ...
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6 views

Satisfactory accuracy for a GEDI geo-locator

What level of accuracy should one expect from a GEDI geo-locator? I'm making a geo-locator for GEDI (similar to https://lpdaac.usgs.gov/news/release-gedi-finder-web-service/ ) and I'm wondering what ...
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1answer
80 views

Partially processing a catalog with an extent in lidR

I am using lidR to create a DEM of a very large area (over 1 million hectares). I have already processed a portion of this area. I would like to be able to read the entire LAScatalog so that the ...
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1answer
37 views

Error in for loop not recognizing writeLAS command

I am currently trying to run a for loop in R that creates las files from a vector of 530 objects (EABplots). I have downloaded lidR, rLiDAR, and the relevant packages that come along with them (sp, ...
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39 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 ...
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1answer
91 views

LAScatalog and shapefile fail to line up in lidR

I am currently trying to read in a catalog of las files (statewide 10TB) and extract around 500 plots from a shapefile of central points. The shapefile reads in correctly, and I have checked it in ...
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81 views

Converting LiDAR log which already in CSV format into PCD format

I have Ouster LiDAR log (LiDAR UDP log file converted into PCAP file and than converted into CSV file). So I want to convert that CSV file data into .pcd file (Point Cloud data format ). CSV file ...
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1answer
35 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 ...
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1answer
99 views

Fitting circles to crescent shaped clusters in raster data automatically

I have mobile lidar scanner (MLS) that was collected in a forest with big, mature trees. My research involves fitting circles to tree stems to estimate their diameters at different heights. Once I ...
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1answer
50 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 ...
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1answer
90 views

Calculate volume of a building using LiDAR data

I would like to use 3D spatial metrics that introduced in the paper titled "Lidar and VHRS data for assessing living quality in cities - An approach based on 3D spatial indices". I have a lidar ...
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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/...
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1answer
55 views

lidR: Error in .bboxCoords(coords) : nrow(coords) > 0 is not TRUE

I'm using lidR to create some lidar metric rasters that match the layout of Landsat images. In the lidR documentation it says this can be done simply by using a RasterLayer instead of a resolution in ...
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1answer
78 views

Speeding-up las files processing in a chunk with buffer [closed]

My aim is to do tree segmentation from lidar data. I have 15 las files and I want to merge them before segmentation. I realized that using chunk with buffer helps to get a proper segmentation. When I ...
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1answer
56 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 ...
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0answers
15 views

Match DSM tiled data [duplicate]

I have an 282 .laz tiles for a large area. The aim was to extract the DSM and DTM data in .asc format to hopefully get building heights from them. I used lastools to convert them the DSM .laz data ...

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