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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2answers
43 views

Can't normalize LiDAR point cloud with lasheight and -replace z (LAStools)

When I try to use lasheight with -replace z to normalize the point cloud, the height of points are changed (destroyed heights; see pictures below). Without using -replace z everything is ok, but the ...
2
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1answer
57 views

Finding the coordinate system info from a LAS/LiDAR file with Python?

I found several examples of how one can query and manually set a coordinate system on a tif/raster file (GDAL/Python: How do I get coordinate system name from SpatialReference? or Is it possible to ...
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1answer
27 views

Create 1' Contours Using Bare Earth Lidar .XYZI Point Data

I have 42 tiles of Lidar .XYZI point data containing approximately 800,000 points each and i need to create 1' contours out of the data. I have access to ArcMAP 10.3 and the 3D Analyst and Spatial ...
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0answers
124 views

Difference in the elevations for the same building on two DSMs saved in *.asc and *.laz formats

The following question concern the same type of data as the one I've asked in Differences in the longitude and latitude between a LiDAR DSM and an optical image. Basically, I've downloaded a tile of ...
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1answer
50 views

Free high resolution DEM or Lidar data for St Lucia

I found the 30m Aster DEM for St Lucia, but am wondering if there is some DEM or other elevation data source (Lidar) with a higher resolution. I googled, but have been unsuccessful in finding any free ...
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0answers
20 views

Can I use georeferenced jpeg raster as map layer in GeoJSON.io?

Can I use georeferenced .jpeg raster as map layer in GeoJSON.io? I thought that I could, but it doesn't work. I converted .tif raster visualization of LiDAR data to georeferenced jpeg. After this, I ...
1
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1answer
34 views

Filtering LiDAR data with las2las by scan angle range?

I am using las2las to filter .las data and I would like to filter the data between a scan angle of -15:+15; however the algorithm tells me the following: ? error bad lexical cast: source type ...
2
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1answer
28 views

Building height in OpenStreetMap

I was wondering if there are some free projects which enable extracting the building height information from openstreetmap data? I downloaded data for a couple of large cities (Manhattan island, ...
2
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1answer
26 views

Update EVLR header info for .LAS file using laspy

I'm trying to change the header info for a LAS file using the python 2.7 (64-bit) laspy module (version 1.2.5). I'm attempting to follow the example shown here (in the section "Writing Data + EVLRS"): ...
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0answers
31 views

Representing multiple polylines in unique vector layer?

I have imported a layer which contains a lot of lines. They overlap each other in a cross kind of pattern. When zoomed out it can look like this: When zooming in on one of the broader lines it ...
8
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2answers
6k views

Building extraction with LiDAR data (Improve Process)

I have the following process for automatically creating building outlines/footprints from Las files and was wondering if anyone can help improve it or has suggestions for other processes to use? ...
2
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1answer
269 views

Extracting LiDAR metrics with TerraScan

I want to extract from a las file statistics such as height percentiles (percentile 95, for example) among others. I can do it with Fusion (using Cloudmetrics and Gridmetrics tools), but I would like ...
7
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2answers
962 views

Normalizing point cloud data

How I can get Digital Height Model (only object heights, DSM - DTM = DHM)? Many applications can do this, but they convert it to GRID or TIN format. I was wondering if it was possible to keep the ...
0
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0answers
50 views

Finding depressions in LiDAR DTM? [duplicate]

I would like to find temporary moist areas based on terrain surface shape (depression) directly from an airborne LiDAR DTM. Could you help me to find some tools or algorithm to solve the task?
2
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1answer
38 views

Recording height profile from raster along a polyline shapefile?

I'm looking for the easiest way to record a series of raster values along a 400 meter transect in ArcGIS 10.3.1. I'm working with a LiDAR canopy height model with 3mx3m cells where each cell ...
3
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0answers
65 views

Visualizing elevation profile across a whole mosaic dataset?

I'm working with many DEMs derived from LiDAR data (IMG format) in a mosaic dataset. This allows me to create hillshade (or shaded relief) functions to display the data, which is great. However it ...
3
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2answers
149 views

Adding LAS files into AutoCAD map 3D with Point Cloud Manager tool

It's my first time to use AutoCAD map 3D for LiDAR. Based on my googling, it is said that I can bring .las file by creating new index and using the Point Cloud Manager tool (the image on the top - ...
3
votes
2answers
205 views

Converting LAS to DWG/DXF using open-source software?

Is there a way to convert LAS point clouds to DWG and/or DXF files using open source software? Also willing to script with Python - is this possible using libLAS/LASlib for example?
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0answers
39 views

Creating 3D interactive model from lidar data using ArcGIS for Desktop? [duplicate]

I have a couple of las files for a city and I need to make a 3D model of the buildings, which should display info about the building when clicked on. I am pretty new to ArcGIS so I don't have the best ...
3
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2answers
873 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 ...
0
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3answers
125 views

Assigning class codes for LAS files? [duplicate]

I have LAS files with code 0 - never classified. I have no other classes other than this. How do I assign class codes for my LAS file?
3
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1answer
319 views

Classifying 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 ...
7
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4answers
11k views

Viewing LIDAR data (.las) in QGIS?

Is there an easy path to visualizing LIDAR data in QGIS? I have some USGS LIDAR data in .las format downloaded from http://lidar.cr.usgs.gov/. This means I have both the .las and metadata in .xml ...
5
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1answer
206 views

Generating surfaces of different heights from LIDAR points

I am seeking a way to generate surfaces (polygons in a 3D space) of different heights from LIDAR point clouds, whose spacing is 4 points per square meter. The typical application is like roofs, which ...
2
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1answer
2k views

Removing pixel values below 0 in Digital Elevation Model in ArcGIS for Desktop?

I made a DEM layer from a .las file (LiDAR). How can I remove the black area which contains negative values? Is it possible to set these values equal zero or null?
2
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1answer
234 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 ...
7
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5answers
6k views

Easy way to create a boundary polygon shapefile from a set of LAS files using ArcGIS 10?

I have a bunch of LAS file sets that I need to process. The current task at hand is to generate a "footprint" shapefile that contains polygons for each LAS tile. I am looking for a graceful way to ...
3
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1answer
149 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. ...
0
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0answers
28 views

How to generate DTM from LiDAR point cloud data? [duplicate]

I have LiDAR point cloud data (X Y Z Intensity), and I want to generate DTM (only ground point). Is there any solution (algorithm or software)?
4
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2answers
327 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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1answer
52 views

Differences in the longitude and latitude between a LiDAR DSM and an optical image

I've downloaded the UK's LiDAR elevation data (see below) in laz format for a specific region (Tewkesbury) from: http://environment.data.gov.uk/ds/survey#/download From that, a DSM (Digital Surface ...
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0answers
54 views

Thinning LiDAR points to remove redundant neighbors?

I'm trying to develop a workflow in ArcGIS with 3D Analyst or Spatial Analyst to intelligently thin a grid of spot elevation points created from a LiDAR DEM. The current point spacing is 1 meter. Some ...
3
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3answers
750 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 ...
2
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0answers
364 views

Format of raw LiDAR data (time-of-flight data)

I am doing a project where I need to simulate LIDAR data, and I am looking for specifications on how raw LIDAR data looks. I want the format of the data before it is translated to x,y,z coordinates (...
4
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1answer
100 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 ...
2
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1answer
794 views

Visualizing a LiDAR point cloud in 3D with GRASS?

I'm new with QGIS and GRASS so I'm sorry if there is a straightforward answer for this question but I can't seem to get it done. I've imported a point cloud into QGIS from a datafile. Now I'd like to ...
1
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2answers
2k views

Tools for exporting coordinates from LAS files to CSV?

Is there any tool available for extracting the X, Y and Z coordinates from a .las file and exporting them to a .csv or similar file?
4
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2answers
159 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 ...
9
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1answer
719 views

Georeferencing LAS files in geographic coordinates (lat/lon) or in cartesian (projected) ones?

First of all, I am a newbie in GIS. I have a lidar point cloud with GPS and telemetry data associated. Then, I transform coordinates of every point to an ECEF coordinate system and finally I ...
3
votes
1answer
158 views

Identifying flightline ID within an LAS file?

I am working with multi pulse LiDAR data that collects points along a number of lines within the flight path. From what it appears there are four scan lines within the data, at different intervals but ...
6
votes
2answers
740 views

Getting the projection of a LAS file using liblas?

I am using the python api of liblas to read/write las files. I would like to get the spatial reference information of the las file using liblas, but have been unable to figure it out. Can anyone ...
0
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0answers
37 views

Matching drone point cloud data with original lidar survey? [duplicate]

I have point cloud data collected from a drone of a particular area. I too have the point cloud data collected from the lidar survey. Both are georeferenced. Now, I need to match the point cloud data ...
1
vote
1answer
115 views

Shifting LiDAR point clouds that have been incorrectly georeferenced

I am new to LiDAR and have never been a part of the LiDAR data pre-processing stage and hence, this question. I have two LiDAR point clouds (.las files) of a densely forested area that were captured ...
2
votes
2answers
81 views

Pixelated DSM using LAS Dataset to Raster?

I am using ArcGIS 10.2.2, and I am trying to create a DSM out of some LIDAR data. After checking the LAS Dataset properties, I see that I have an average point spacing of approx 0.3. I tried ...
2
votes
1answer
46 views

Assigning CRS using las2las from libLAS?

My las file had a spatial reference of "None." I tried to assign the CRS (in which data were collected) with the following command line: las2las flightline_002.las --a_srs EPSG:32632 lasinfo --no-...
5
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2answers
103 views

Improve DTM under forested areas without smoothing?

I'm using a DTM retrieved from LiDAR data and I noticed that forested areas are grainy or not defined. The DTM data was retrieved from geostore.com. Here is one example: Is there any way to ...
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0answers
75 views

Classifying building walls from LiDAR point cloud [closed]

I am currently working on mobile point clouds in order to extract 3D building models in the residential area. I could successfully classify ground, vegetation and building roof lines, but still have ...
4
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0answers
56 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 ...
8
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2answers
3k views

What are LiDAR returns?

Can someone help with an explanation and some references, in order to understand the nature of return pulses within a LiDAR system.
1
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0answers
70 views

Caching LiDAR Image Service outside of ArcGIS to send to ArcGIS Server? [closed]

I have very limited programming/coding experience. We are hosting a number of LiDAR services on ArcGIS Server, and need 24 of these to be cached, from 1:500,000 to 1:4,000. We initially had ...