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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3
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1answer
82 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 ...
4
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1answer
121 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 ...
6
votes
1answer
277 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 ...
0
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0answers
112 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 ...
4
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2answers
154 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?
3
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1answer
184 views

Exporting crown boundaries from tree segmentation in R?

I am using lidR package to segment my trees using lastrees directly from the points clouds. The function works fine, however I would like to export to vector file the canopy boundaries from ...
1
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2answers
1k views

laspy ValueError: buffer size must be a multiple of element size

I am trying to learn LASPY and am running into road blocks off the bat. I first ran into and Error 8 (Not enough storage is available to process this command) using my full sized LAS file (1.7GB). I ...
3
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1answer
131 views

Interpolating LiDAR intensity images in R?

I'd like to generate 0.5 m intensity images using lidR, but the resulting raster is full of pits. Here's a reproducible example: library(lidR) LASfile <- system.file("extdata", "MixedConifer.laz", ...
1
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1answer
202 views

Seeking LAG LiDAR Analysis GUI installation guide?

Does anyone know how do I install LAG lidar Analysis Gui? LAG by arsf This is my situation: I'm using debian 8 test. I installed this library: boost (yes) * GTKmm (yes) * GTKGLextmm (yes) * GThread (...
2
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0answers
68 views

Importing several LiDAR (.las) files in GRASS using v.in.lidar?

I'm building a DEM of a terrain in GRASS and have 48 LiDAR (.las) files. I know I can do this by using r.in.lidar (including the list of files as a .txt) and then r.fillnulls However, I want to ...
2
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1answer
60 views

Non-constant transformation of photogrammetric point clouds in R?

I have a process which attempts to register two forested point clouds using CloudCompare's Iterative Closest Point (ICP) algorithm. Often times, warping (especially in the vertical direction) occurs ...
3
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1answer
255 views

Visualizing vertical profiles from LiDAR point clouds in R?

I would like to visualize the vertical profiles of different LiDAR point clouds in different forest types. I have extracted the z-values from the LiDAR files with lidR and put them in a dataframe with ...
3
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1answer
158 views

Filtering (lasfilter on) huge LiDAR dataset

My dataset is about 8.3 GB after loaded into R environment by using lidR package. Some points which have return number greater than number of returns need to be removed. With a small dataset, I ...
3
votes
1answer
152 views

Getting source bounds when filtering LAS using PDAL?

I'm using PDAL to filter out non ground points to create a DTM along with a DSM also made through PDAL to create a Canopy Height Model using this method. My workflow looks like this. #!/bin/sh # ...
2
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1answer
160 views

Extracting projection from each LAS file in directory using ArcPy?

I am using ArcPy to automate the conversion of LAS files to Raster in ArcGIS. I'd like to extract the spatial reference from each LAS file along the way. Is it possible to do this using ArcPy tools?...
1
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0answers
35 views

Creating Left and Right Image pair to view with 3D goggles in stereo from DEM or Hillshade?

How does one create the stereo pair for viewing in a program such as StereoPhoto Maker? I have processed lidar that I'd like to turn into hillshades and then view in this kind of software, with 3D ...
1
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1answer
98 views

Resampling 0.7 m LiDAR (in raster already) to 10 m DEM in R?

How do I resample the 0.7 m LiDAR to 10 m DEM in R? What are the basic rules for checking the consistency?
3
votes
1answer
230 views

Calculating standard metrics in multiple LiDAR files with lidR 2.0

I am porting my existing code to lidR version 2.0 and would like someone to let me know if I am coding efficiently. My objective is: to process a directory of LAS files normalize las files calculate ...
2
votes
1answer
515 views

Using Python to send arguments to LAStools basics

I'm currently trying to develop a LAStools specific routine, setting all the parameters for lasheight then using the output of that to run lasclassify. The closest thing I've found to being able to ...
6
votes
1answer
443 views

Laspy exception: “Invalid format”

I am attempting to open a couple of las files in laspy, however one of them has file version 6.0 (although it does not show up as such in lasinfo - I may be missing something). Digging through the ...
1
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2answers
107 views

Getting statistics in cross sections at varying heights in LAS files?

I am looking to cross section my forest at varying heights. I have high return LAS data (8 points/m2 and average point spacing of 0.2m) and I am looking to do more than the simple 1, 2, 3 approach of ...
4
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2answers
343 views

How to filter point cloud by flightline in R?

The lidR package in R provides a way to mark individual points in a point cloud with a flightline ID by using lasflightline(). From the documentation: Retrieve each individual flightline by ...
2
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1answer
176 views

Preventing interpolation outside of data extent with LAS Dataset To Raster ArcMap?

When I use the LAS Dataset To Raster tool in ArcMap I get an unwanted interpolation outside of the actual study area, like this: According to Esri this can be prevented by changing the definition of ...
1
vote
1answer
49 views

Displaying pointcloud symbolized with RGB values in ArcMap?

I know that I can display a LAS dataset in ArcScene with RGB Symbology, but is there a way of doing this in the 3D View window in ArcMap? The LAS Dataset toolbar only has symbology for elevation, ...
1
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1answer
70 views

How to identify understorey forest structure using airborne full waveform lidar data? [closed]

I am learning how to use lidar to study forest structures, but I cannot find any methodology on how to map understory trees. It is for a school project where I am mapping forest developmental phases ...
1
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2answers
73 views

Locate LAS Points By Proximity gives ERROR 999999?

I am trying to locate LAS points which is within a specific distance (25cm or 50cm) from the 3D points in a feature class. This is exactly what the Locate LAS Points By Proximity tool should do. My ...
2
votes
1answer
62 views

Whitebox Tools ClipLidarToPolygon writes no points to output file?

Running Whitebox Tools (v 0.11) on Windows from the official binary. The ClipLidarToPolygon tool creates an output LAS file with no points and the message There are fewer than two points in the LAS ...
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3answers
166 views

Maximum number of returns per laser pulse in airborne LiDAR?

What is the maximum amount of returns a discrete aerial laser scanner is capable of recording? For example in a LAS 1.2 metadata under Point Data Records there is the category 'Number of Returns' ...
0
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1answer
64 views

PDAL info with docker yields no output?

I am using pdal info within a docker env for a specific .las file (~2 GB). docker run -v /Users/user.name/workspaces/testData:/data pdal/pdal pdal info /data/sp.las --developer-debug Unfortunately, ...
-1
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1answer
192 views

Seeking LiDAR data for Palawan (Philippines)?

Is there any public or private sources of LIDAR data for San Paul river in Palawan (Philippines)? Searching online has not lead me to any sources, and I am unsure how the commercial world of LIDAR ...
10
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5answers
12k views

Clipping LAS data using shapefile polygons and open source software?

I am trying to clip or filter lidar files (.las, .xyz) using a shapefile that contains multiple polygons. Is there open source software that can do this spatial operation? My .las files are enormous,...
2
votes
1answer
218 views

Importing point cloud data to Terrascan is incorrectly gridding it?

I am using Terrascan to strip vegetation of some ASCII files to create a bare earth model and also to convert the ASCII txt file into a *las (1.2) file. However, I have noticed that Terrascan (at ...
1
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1answer
313 views

Splitting LAS file into smaller LAS files by shapefile geometry boundaries - using PDAL or Global Mapper. [duplicate]

I've looked up pdal documentation on how to clip LAS point cloud files:- https://pdal.io/workshop/exercises/analysis/clipping/clipping.html Referencing this example, and having a quick look around, ...
2
votes
2answers
359 views

Using LAStools to repair headers for several LiDAR files?

So, I have 21 LiDAR files with incorrect information in their file headers. For example, when I import a single file into R using the following code, I get several warnings saying that there are no ...
6
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4answers
1k views

Reaching cm (inch) level elevation precision using drones

A road construction firm needs altitude data of road path before and after the construction and the error should be less than 3 cm (2 inch). Normally, they put a ground station and workers manually ...
1
vote
2answers
180 views

File header incorrectly reporting 0 point records in R?

I have a set of 10 LiDAR files that I'm attempting to retile and eventually use to create a Canopy Height model. I'm able to import them as a catalog, however when I go to retile my catalog, I get the ...
4
votes
1answer
247 views

Cropping raster and merge it to overlapping DEM?

I am working with an existing DEM of a river and its surrounding area in QGIS (actually a virtual raster from four separate DEM TIF tiles). My goal is to add a bridge's profile to the DEM. I have a ...
1
vote
1answer
137 views

Converting LAS to TIFF using Arcpy - TIFFs writing out empty

I am using ArcPy to convert large batches of LAS files to GeoTIFF format. It seems like a lot of the data I have acquired from a particular source is giving me the same error: I am able to convert ...
5
votes
1answer
149 views

Choosing Topographic Wetness Index or Flow Accumulation raster?

What is the better raster to use qualitatively - Topographic Wetness Index or Flow Accumulation - to clearly see potential areas of surface flow/wetness across a landscape? As an example, what's "...
8
votes
4answers
3k views

Thinning large LiDAR point cloud?

I have a large point cloud (LAS file) and I am trying to thin this using a complex technique. I know it is possible to thin a point cloud using simple techniques such as extracting every nth point. ...
2
votes
1answer
591 views

Why ground model from point cloud in Global Mapper is inaccurate?

I have a LAS file that I assumed was based on LiDAR, but it is actually based on ADS (airborne digital sensor) imagery, according to the body that captured the data. I load the file in to Global ...
9
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3answers
498 views

Difference between LAStools, libLAS and PDAL?

After many readings, I'm still confused about the difference of use and the aims of the following tools for LiDAR data processing and manipulation: LAStools, libLAS, and PDAL. My understanding so far ...
1
vote
1answer
73 views

Estimating building and vegetation volume with unclassified LiDAR datasets?

I'm trying to determine the ratio of building to vegetation change (i.e. how has the volume of built structures changed in proportion to the volume of vegetation) in a city over a period of five years....
3
votes
1answer
82 views

Interpreting cell coordinates from DEM?

I'm using Environment Agency DTM LiDAR data which I import into Mathematica in ASCII format to produce ground surface models, sections, etc. The process works fine, but I'm unclear whether the cell ...
1
vote
1answer
70 views

LiDAR data in GPS time, only in second. Missing week?

I have LiDAR data LiDAR Data captured, unsure what units or format this time field is in? which I learned that my LiDAR data is in GPS second, however I do not have a column of data which shows the ...
2
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0answers
56 views

Speckle on LiDAR data

Does LiDAR data suffer from the speckle noise like the SAR images and ultrasound cardiac images I'm used to? I think speckle noise is inherent to all active sensors, but I'm not sure for LiDAR ...
3
votes
1answer
2k views

Open a SBET file format in GIS software

After a LiDAR flight, we can get a file containing the airplane trajectory in SBET format - Smoothed Best Estimate of Trajectory. Is it possible to open it in a GIS software like QGIS or ArcGIS? If ...
2
votes
1answer
299 views

LAS/LAZ parser for NodeJS

I cannot find any popular libraries for parsing (reading into memory) of LAS or LAZ (lidar data) files in NodeJS (desktop Javascript) https://github.com/yuyou/liblas4node/blob/master/lib/liblas.js ...
4
votes
1answer
1k views

Accessing raw data from LAZ file in Python with Open Source software?

Is there anyway to access raw "LAZ" (not LAS) datasets in Python? I was trying to with ArcPy (I'd prefer not too), but it doesn't seem able to access LAZ. I'd prefer to work with the raw LAZ file and ...
2
votes
3answers
2k views

Running LAStools on QGIS 2.8: “missing dependency. lastools folder is not configured”

To be honest I'm not sure how to run LAStools from within QGIS 2.8. I'm trying to learn by experimentation. QGIS shows all the LAStools in the toolbox If I double click on a LAStool in the toolbox I ...