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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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0answers
24 views

Seeking roadway data collection solution ideas? [closed]

I work as a technical/GIS analyst for an asset management company, and I've been tasked with researching ways that LiDAR may possibly streamline our workflow. Essentially we are looking for a more ...
3
votes
1answer
53 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 ...
2
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0answers
43 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
39 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
63 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
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1answer
119 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
132 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 ...
3
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1answer
76 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", ...
2
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1answer
75 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
16 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
59 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?
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0answers
25 views

Resampling 0.7m Lidar to 10m DEM in ArcGIS Desktop? [duplicate]

How do I resample the 0.7 m lidar to 10 DEM in ArcGIS Desktop? What are the basic rules for checking the consistency?
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0answers
41 views

Why is my watershed delineation different- burned DEM vs non burned DEM?

Using ArcMap 10.4, I am trying to capture potential overland flow of farm ponds in a small watershedu. I've followed the typical steps for preparing a DEM for watershed delineation (pit removal, flow ...
3
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1answer
87 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 ...
3
votes
1answer
78 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 # ...
1
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1answer
39 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
vote
1answer
39 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
vote
2answers
123 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 ...
1
vote
1answer
98 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 ...
1
vote
1answer
151 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 ...
1
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2answers
121 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 ...
9
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3answers
186 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
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1answer
43 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 ...
1
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1answer
38 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?
2
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0answers
43 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 ...
5
votes
1answer
82 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 "...
1
vote
1answer
32 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
72 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 ...
4
votes
1answer
323 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 ...
1
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1answer
101 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, ...
3
votes
1answer
100 views

Error in reading point cloud data (.las) in R?

I want to generate a DEM using a point cloud (.las) for which I tried reading it in R using rlas, lidR and rLiDAR : readLAS command and none of it seems to work. The LASfile is not being read at all....
2
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0answers
45 views

Parallel optimization for query over LiDAR dataset

I'm using PostGIS + pointcloud to store a huge dataset of LiDAR point (2M patches of 600points) I query this database to obtain the altimetic profile between two points. At the moment I have a huge ...
2
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1answer
200 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 ...
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1answer
77 views

LIDAR scans of the same location give very different values [closed]

In QGIS, I have a number of LIDAR scans of the same geographic location over a number of years. The actual values in the .asc files differ markedly (see image). Do the different value ranges for the ...
2
votes
1answer
101 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 ...
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1answer
79 views

Combing multiple LAS files with different vertical and horizontal accuracy?

The data set in question was made using .las and .zlas files from respectable sources. Data set 1 was collected in the Fall of 2014. The RAW flight line swath data was processed to create classified ...
1
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3answers
91 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' ...
3
votes
1answer
70 views

Constructing a function to pass to lidR::grid_metrics

I am attempting to write an R function, as part of a package, that takes a lidar tile (LAS object) and a vector of cut-points defining vertical layers, and returns a RasterStack where each layer has a ...
1
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0answers
47 views

LiDAR first and lastreturns eCognition [closed]

Recently I downloaded the new version of eCognition Developer. I remember that before when processing LiDAR data by using algorithms it is pretty easy to generate LiDAR first and last returns. ...
1
vote
1answer
134 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 ...
2
votes
1answer
49 views

Extracting Road Terrain Properties using DEM / LIDAR

I want to extract following road terrain data from DEM but I'm not sure if its possible. Can i extract these attributes using LIDAR if not DEM ? These are the data fields I need: Horizontal curve ...
0
votes
1answer
41 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, ...
2
votes
1answer
67 views

Optimizing workflow for FUSION's PolyClipData?

I have multiple large LiDAR datasets (.laz) from different areas, where I need to extract buildings. I have prepared a shapefile containing a buffer around the buildings I care about, and are using ...
2
votes
1answer
40 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 ...
1
vote
1answer
256 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.
1
vote
2answers
128 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 ...
3
votes
1answer
165 views

Digitize objects in a LiDAR point cloud?

I am working with LiDAR point cloud data of road networks. The goal is to digitize all visible objects like hydrants, streets, sidewalks. My input data is available in LAS or ASCII format. My first ...
1
vote
2answers
106 views

Saving LAZ files to different location from input (LAS) files? [duplicate]

All of the command line examples I'm seeing show how to create LAZ files in the same folder as the LAS files, e.g.: C:\Folder\tools>laszip F:\Folder\LAS_points\*.las Unfortunately, I don't have ...
2
votes
1answer
168 views

Importing LiDAR point cloud classes in Potree?

I can't find a way to import classes (roof, vegetation, ground, etc..) in Potree. I generated the web page, except I get the black point cloud. When I, for example, open .las file in ERDAS Imagine, I ...
4
votes
2answers
372 views

Why did Esri create .zlas compressed LiDAR files instead of adopting .laz?

I am talking about the Esri Optimized LAS file format for compressed LiDAR files (.zlas). While the uncompressed format (.las) from ASPRS was adopted by practically the entire Remote Sensing and GIS ...