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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74 views

Options for visualizing LiDAR data on (Mac) OS X?

I've recently come across open data LiDAR files for the city of Vancouver. I'd like to view it on my Mac (2011. 10.6.6 OS). My intention is to use the LAS file to identify what the tallest trees are ...
4
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1answer
93 views

Importing LAS files in QGIS with LAStools gives an 'ascii encode error'

I'm new to QGIS environment and I am trying to load LAS files into QGIS with lasground but when I run the following process an error occurs: 'ascii' codec can't encode character u'\u0105' in ...
4
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1answer
60 views

Importing LiDAR .txt in QGIS for map conversion

I have LiDAR data in .txt files (1000 to 26000 KB), where 2nd column marks x-coordinates, 3rd col y and 4th col z. 8 485000.16 6508997.48 1.84 66 Last 2 485001.27 6508998.92 1.86 82 Last 2 485001.02 ...
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1answer
505 views

Failing to merge rasters in QGIS

I am new to QGIS but have some familiarity with other GIS software (namely ArcGIS). I want to merge a number of LiDAR digital elevation model (DEM) tiles (specifically, 30 individual tiles) to ...
4
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1answer
292 views

What are definitions of watershed segmentation, local maxima, variable window search, regarding LiDAR for vegetation?

I am not familiar about Lidar. I want to measure trees height and number of trees. I guess, watershed = to locate the trees, local maxima = to measure trees height. I used these methods in SAGA GIS. ...
4
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2answers
2k views

Drawing irregularly shaped boundary polygon around set of LAS points using ArcMap?

I am working with a set of LAS data which is irregularly shaped, picture a starfish as the point coverage, surrounding the starfish may be water on one side, may be more land elsewhere but no points ...
4
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1answer
875 views

How to repair and clean contours from high data resolution (lidar)?

I'm unsuccessfully trying to make a bathymetric map with contours extracted from Lidar data at 1 m resolution. The extracted contours have a lot of artifacts like dangles and islands. First I used ...
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2answers
848 views

Retrieving average building height in urban areas

I am looking for a way to collect data on the height profile of some cities over time. I don't need to produce a detailed 3D reconstruction of cities, nor do I need to detect and measure individual ...
4
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1answer
68 views

30m/10m/1m resolution DEM for microtopography research

I am conducting research in a region of Illinois that does not have a LiDAR dataset. I am looking to develop a fine scale habitat species distribution model; however, the coarse data available ...
4
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1answer
126 views

Raster cells with no data being generated by las2dem?

Anyone has an idea where these lines (with no elevation data) come from? They are generated while using the las2dem tool from LAStools. What needs to be done to avoid this? The raw data (.las file) ...
4
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1answer
258 views

Workflow for generation of contours with LiDAR data and OCAD

I am updating our maps for an orienteering club in Illinois. I was very excited to find out that we have access to .las lidar data in 2000x2000ft files. I checked out OCAD11 and it can handle .las ...
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0answers
53 views

Why do first returns have more blanks than last returns in LiDAR data? [closed]

I'm working on an ASCII LiDAR file that has the first and last pulse returns included. Can anyone tell me why a first pulse return may come back with more blank spaces in the data than a last pulse ...
4
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0answers
44 views

How to get NIR values into a LAS file then a CSV?

We are trying to deliver a LAS file with NIR values added for each point. The NIR comes from a raster captured at the same moment as the LiDAR, and is stored as an 8bit number along with RGB in 8bit. ...
4
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1answer
288 views

Site viewshed with DSM: removing “false” visibility readings from trees and buildings

I've been working on modeling a proposed building and running a visibility analysis to determine from what areas the building could potentially be seen using ArcGIS Desktop with 3D Analyst. Using a ...
3
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5answers
7k views

How to convert LAS to GRID/Raster for ArcGIS input?

I was wondering if there is an option to convert LAS (LIDAR data) to raster or GRID format that ArcGIS could read it.
3
votes
2answers
348 views

Where I can find real world data for triangulation? [duplicate]

I want points for practicing triangulation algorithms. Just points with coordinates [X,Y] and elevation [Z] of real world terrain. I can use Google Maps Elevation API, but there is no method how to ...
3
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3answers
402 views

Removing duplicates from large LAS files

Are there any publicly and free (not necessarily open-source) applications that can remove duplicate points from LiDAR clouds? I would like something on the lines of lasduplicate -unique_xyz, which ...
3
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1answer
101 views

Converting between coordinate systems for LAS file using LASPY

I am trying to convert a .las file from WGS84 to UTM17. I have some drone imagery that was used to generate a 3d point cloud/ .las file, but it is in latitude/ longitude instead of easting/ northing. ...
3
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2answers
128 views

Retrieving LiDAR metrics from relative vertical layers of point cloud

I need to obtain the proportion of all returns within 5 equally spaced height bins between the cutoff (1 meter) and the maximum height value. I need to get this proportion of all returns for 1000 ...
3
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2answers
259 views

Creating DEM from las file without using Lastools

I want to create a ground model from a *.las file. The LAStools are available in QGIS but limited in use (generation of black diagonal in result file), so I can't use this. In the GRASS tools I can ...
3
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1answer
37 views

How does the offset values of LAS files relate to their coordinate system?

I have a conundrum concerning LiDAR data, the stored point offset, and the coordinate system. I process large amounts of LAS data in TerraScan (TS), which sits on top of Microstation (MS). I receive ...
3
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2answers
259 views

LIDAR online training

Beside ESRI's LIDAR online training, I'd like to work on some hands-on training that I can learn about LIDAR. Are there any good LIDAR out there that I can get some training with the datasets ? ...
3
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2answers
71 views

Using ASCII LiDAR data tiles which are centimeter rounded (n Z) in ArcGIS Desktop seems to round them to meters?

I try to use four LIDAR tiles in .asc with arcgis9.3. All of this tiles are centimeter round (in z) but one of them seems to be round to meter (see tile on the left up corner on the image below), ...
3
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2answers
530 views

Removing incorrect (non-ground) points from LiDAR data? [duplicate]

I have ground lidar points, nonground lidar points and tree lidar points. The problem is some of the ground lidar points are incorrect. For example, the highest elevation values of tree and building ...
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3answers
2k views

Creating DSM and DTM from a LAS using a freeware solution

Is it possible to export a surface and terrain model files from an aerial, LiDAR point cloud (LAS) set? I am using SAGA GIS for very basic operations, but I couldn't find this option (and I have a ...
3
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2answers
884 views

Canopy Height Model of LiDAR data in QGIS?

I am having a DTM and DSM files. I want to develop a Canopy Height Model in QGIS. Is it possible?
3
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2answers
177 views

LiDAR intensity image from multiple flight lines?

I'm working with multiple raw las tiles, and I've used Fusion to create an intensity image, but it shows the flight line overlap (see below). Any idea how can I smooth the image so that the overlap is ...
3
votes
1answer
212 views

What's the deal with “degradation” and lastools?

I've read a few cautions online and heard a few from colleagues. If you don't purchase a license for lastools, the non-open-source functions will somehow degrade your data or results? Is this true? ...
3
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2answers
674 views

Lidar data in ArcGIS 10.1

Problem: I have a set of LAS files that doesn't display in Arcmap. Details: I try to use LAS to tin in Arcmap to convert my LAS points to a TIN. However, when browsing to the folder with the files, ...
3
votes
1answer
269 views

Problem with MCC-LiDAR (insufficient memory)

I am running mcc-lidar on a win7 64bits with 16gb of ram. Nevertheless when I try to process a las file with 1, 800 000 points using -s 0.5 and -t 0.3 the program tells me: Error: insufficient ...
3
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2answers
505 views

How to clip from a point layer using postgis?

I've loaded a LIDAR xyz file into a PostGIS2.0 database and created a 3D point geometry column ("tblCLOUD") from the data. I've also loaded into the database a shapefile that contains six ...
3
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1answer
36 views

Do outputs (shp, dwg) inherit vertical datum from input (las) files?

I'm working in ArcMap. I pulled LiDAR data off earth explorer and created a DEM with the LiDAR data. I then created contours as a SHP file and exported to DWG (CAD). I was asked if the CAD file's ...
3
votes
1answer
224 views

Clip multiple .las files data to polygon shapefile using FUSION

I followed this thread in order to clip .las data based off of a polygon shapefile. However I have over 100 .las files I need to clip based off of this polygon and merged into a single .lasd file and ...
3
votes
1answer
164 views

Elevation maps from point clouds: TPS vs. what other methods

In the reply to another question, @thehealingprocess refers to "...a comparison of interpolation methods for interpolating elevation maps from LiDAR clouds, and in almost all scenarios thin ...
3
votes
2answers
676 views

How to connect contour lines from two different sources?

How to connect contour lines from two different sources (LiDAR & Photogarametry) in order to obtain continuous and uniform contour lines layer ? how can i interpolate them together ? How can i ...
3
votes
1answer
185 views

QGIS 2.14.1 LAStools install error: “wrong value for parameter 'Msys folder'…”

I went to step 4 from rapidlasso.com guide and extracted LAStools to my C drive and just made the folder there. I can't do step 8 because it seems to already be in "advanced interface". Then, step 9 ...
3
votes
1answer
72 views

How exactly does a single laser pulse from LiDAR act? [duplicate]

I'm trying to understand the behavior of a single laser pulse in a traditional airborne lidar. I understand that the multiple return values are representative of the surface that reflected the ...
3
votes
1answer
101 views

How to exclude water during contour generation?

I recently acquired a LiDAR data set that included a 1 meter DEM. I generated 1, 2 and 5m contour layers but I am seeing a lot of contours within water bodies. I suspect this is either caused by wave ...
3
votes
1answer
100 views

Is it possible to have v.in.lidar without compiling GRASS?

I already have installed libLAS like this: sudo apt-get install liblas-bin And Ì have installed GRASS GIS 7 from the ubuntugis-unstable repository. Is it possible v.in.lidar without compiling ...
3
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2answers
70 views

Coordinate formatting for swath data - to polygon

I've got a CSV of Lidar coverage swaths in the below format. Each run or strip is tied together via run_id. I'm assuming L is for left, R is for right and M is for middle. EDIT: These are coordinates ...
3
votes
1answer
82 views

Calculate change in canopy height over 10 years?

I want to know how many "tall" trees (greater than 30 m) fell down between 2005 and 2015. I have LIDAR imagery from 2005 and 2015 from an area where many tall trees are known to have fallen due to ...
3
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1answer
807 views

wine + LAStools in QGIS 2.8.1, Ubuntu 14.04

I can't get wine + LAStools to work in QGIS 2.8.1 (ubuntu 14.04). I only get the 22 open source functions that comes with QGIS. Outside qgis wine + LAStools works fine. My guess is that I am not ...
3
votes
1answer
393 views

DEM creation with C++ application

I am implementing a C++ application that must produce DEMs from LIDAR data. I am following the next workflow: Write .las files from lidar data. Use PCL algorithms to transform/filter the point ...
3
votes
1answer
264 views

Classification of above ground LiDAR points in ArcMap

I recently used the LAS Dataset toolbar to classify a .lasd file. The process classified the majority of points as unassigned with the rest being ground points. The study area has many tall buildings ...
3
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3answers
2k views

Problem using LAStools in QGIS 2.6.1: “global name 'os' is not defined”

I have a problem with LAStools in QGIS 2.6.1. I have never used QGIS to process LiDAR data before. I downloaded LAStools yesterday from the rapidlasso GmbH website. I unzipped the “lastools.zip” ...
3
votes
1answer
277 views

How complete are the Fusion tools in QGIS?

How complete are the Fusion tools in QGIS? I have them installed and (vaguely) working, but there are only about ten of them. Is the idea of having just a few tools available, that one can use ...
3
votes
1answer
54 views

Algorithm behind custom tool of ArcGIS for Desktop called xyz2grid21?

I am a researcher from Romania and I have used xyz2grid21 ArcGIS tool (by Min-Lang Huang) in order to convert xyz files (LIDAR data) to ASCII and ESRI grid in order to obtain a DTM. I need to know ...
3
votes
1answer
231 views

Convert coordinate system of Lidar or TIN?

I have Lidar data and I want to create a TIN from it, and then run the TIN Triangle tool to create a polygon shapefile of the triangles. The only thing is that the Lidar data is in a UTM CS with ...
3
votes
1answer
236 views

Lidar and Opengeo suite

Opengeo suite has provided a tutorial on how to manage LiDAR data using postgresql. I was trying to follow the tutorial in this link. I am new to Linux and using Ubuntu 12.04. I have successfully ...
3
votes
1answer
253 views

Correcting class codes of LiDAR files in ArcGIS

Is there any procedure to automatically correct lidar classification? My LAS Dataset has water listed as ground and buildings listed as vegetation. Just wondering if there is any option to fix this. ...