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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35
votes
2answers
15k views

Proper workflow for LAS to DEM conversion

I regularly come across LiDAR (.LAS) files with elevation data. When I do, I always struggle to find a way of converting them to a DEM for hydrological analysis. I have developed several workflows, ...
28
votes
7answers
18k views

Methodology for creating accurate drainage networks (and catchments) from high resolution LiDAR DEM?

This is not the first time I've stumbled over this issue; it seems that I am unable to generate a correct drainage network model and the resulting catchments from full resolution (1m cells) LiDAR data....
25
votes
12answers
27k views

Working with LiDAR data using other than Esri software?

I will be working with LiDAR data soon and I am wondering what the alternatives to using Esri software to do this are, including open source solutions?
22
votes
6answers
17k views

What LiDAR processing tools are available in Python?

I have been using FUSION and the command line FUSION Lidar Toolkit (LTK) to process LiDAR data. A broad Google search ("Lidar Python") yielded libLAS and pyLAS as Python LiDAR libraries, however, ...
20
votes
9answers
15k views

Viewing LiDAR data from web browser?

I am looking to host lidar data on my own server and give clients the ability to view that data through a web browser as a 3D point cloud (file would be in .las format or equivalent), possibly with ...
18
votes
3answers
2k views

Account for bridge overpasses in a ground DEM to allow for water flow under the overpass

I have a bare earth DEM made from lidar data (A). It works well and has passed all accuracy tests. It is used in storm surge models. The problem we are having is on underpasses. I need to allow water ...
16
votes
9answers
38k views

Converting XYZ files (with regularly spaced xy) to ESRI GRID format?

Normally consultants (LiDAR survey) provide me with data to my specifications; already in ESRI GRID or ASCII GRID format. This way LiDAR data can be easily used with ArcGIS. This time I only have xyz ...
16
votes
7answers
35k 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 ...
16
votes
3answers
3k views

Optimize nearest neighbor query on 70 million point cloud on SQL Server 2008

I have about 75 million records in a SQL Server 2008 R2 Express database. Each is a lat long corresponding to some value. The table has geography column. I am trying to find one nearest neighbor for a ...
14
votes
16answers
25k views

Seeking point cloud (LiDAR) data? [closed]

Is there any freely available pointcloud data? I'm especially interested in dense clouds of small areas(5m to 100m radius) but anything else would be fine too. I've found that these pages have ...
14
votes
4answers
2k views

Performing dikes extraction from DEM?

I do have DEM of 1x1 meter and original LiDAR point cloud in .las, that DEM is made of. I need to extract river dikes (highest points of the dikes) to vector feature (point, polyline). Any idea for ...
14
votes
6answers
2k views

Ways to visualize multiple large LiDAR tiles?

I want to load approximately 10 large LiDAR tiles for analysis. I have tried using ArcScene but it appears there is a limit on how much data ArcScene can handle at one time. Each tile is 65-90MB in ...
14
votes
3answers
5k views

Converting LAS file to numpy array?

I have begun learning how to manipulate LAS data in python and wanted to see how others handle LAS files. I would like to read the points (I am using a numpy array), and filter out classes 1 and 2 (...
14
votes
2answers
5k views

Huge point cloud laser data in PostGIS - Storing and Processing it

I wonder, how it's possible to store huge sets of laser scanned point cloud data in PostGIS, with the time-aspect for processing it in mind. I know, there exists a geometry-object Point in PostGIS. ...
13
votes
3answers
5k views

Benefits of *.las vs *.xyz or *.ascii when working with LiDAR in ArcGIS for Desktop?

From time to time, we use LiDAR data for modelling in ArcGIS. Previously, we would be supplied either an .xyz or .ascii of the data, but more recently, we are also being provided .las files in ...
12
votes
2answers
13k 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.
12
votes
5answers
5k views

Extracting tree crown areas from remote sensing data (visual images and LiDAR)

I am looking for a method to process a remote sensing image and extract the crown areas of the individual trees from the image. I have both visual wavelength areal imagery, and lidar data from the ...
12
votes
4answers
5k views

Comparing two Digital Elevation Models (DEMs) from LAS files?

I have two LiDAR files (.las), one is original let's say with X points. And the other is copy of the first .las file but with Y points, where Y is less than X. Now, I want to compare the Digital ...
12
votes
2answers
1k views

PostGIS interpolation / triangulation options

I'm looking for an open source workflow to automate DEM construction. We have a series of sites that fall within a LIDAR dataset. We want to create site specific DEM's for each site, and we're ...
12
votes
1answer
9k 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? ...
11
votes
7answers
11k views

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

I went to step 4 from How to install LAStools toolbox in QGIS 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 ...
11
votes
3answers
9k views

Best method to aggregate 1m DEM mosaic to 10m DEM

I have a mosaic of a 1m LiDar derived DEM. I need to output a subset of the data as a 10m DEM. I am currently using the aggregate tool in ARCGIS 10 to produce a mean value for each new 10m pixel. ...
10
votes
4answers
7k views

Determining bare earth DEM from unclassified LAS file?

I have data in LAS format with RGB values created from aerial photogrammetry using a UAV. I am trying to find a solution to extract the bare earth DEM from the point cloud. I have tried SAGA, ...
10
votes
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,...
10
votes
4answers
4k views

Assigning RGB values from Geotiff image to LiDAR data, using R

I have given a Geotiff image and its corresponding Lidar data (x,y,z) in UTM coordinates. I need to merge the Lidar data with the RGB values from the image. That means, at the end, I need to plot (...
10
votes
5answers
2k views

Processing full-waveform LiDAR?

Does anyone know of a good software package for processing full-waveform lidar? Also, does anyone know of a good tutorial on processing full-waveform lidar?
10
votes
2answers
2k views

Combining high resolution and generalized hillshade rasters to produce enhanced shaded relief?

I often add LiDAR data to a map along with a shaded relief. Most of the time I have to generalize the LiDAR DEM depending on the scale of the map. Still, there is often too much detail and mountain ...
10
votes
8answers
4k views

Editing LiDAR point cloud to remove noise/outliers present below and above ground?

I have "dirty" LiDAR data containing first and last returns and also inevitably errors under and over the surface level. (screenshot) I have SAGA, QGIS, ESRI and FME at hand, but no real method. What ...
10
votes
2answers
444 views

Cleaning blocks pattern from urban LIDAR (blocks uplifted from streets)

We have a 1-meter LIDAR DEM from a city. A small subset can be downloaded from this link: This screenshot shows raw DEM with gray palette (darker belts are streets, and greyish and whitish ...
10
votes
5answers
12k views

Creating boundary polygon shapefile from set of LAS files using ArcGIS Desktop?

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 ...
10
votes
7answers
8k views

Linux alternatives to visualize and analyze LiDAR datasets?

For a long time I have been using softwares based in Windows to visualize and analyze LiDAR data sets for forest application. Recently, I have started to move all my work to Ubuntu platform, but I'm ...
10
votes
3answers
27k views

Converting LiDAR files from LAZ to LAS format

I'm trying to convert LiDAR files from the LAZ format (the compressed version) into LAS (the uncompressed version) using LASzip software. However, I am not really sure how it works. I created a new ...
10
votes
1answer
2k views

How to display dynamic raster (lidar) data on a Web map?

I have some high quality LiDAR data. I need to process it dynamically, and update a field (not elevation field) depending on my input and elevation at that point. Once this is done, I need to display ...
9
votes
3answers
468 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 ...
9
votes
3answers
5k views

Workflow for determining stream gradient?

As far as data goes, I'm working with NHD .shp files, 10m DEMs, and some LIDAR data. My goal is to determine gradient for 100m segments of a network of streams. I'm already able to do this, but I ...
9
votes
3answers
4k views

What to consider when hiring aerial LiDAR survey? [closed]

My organization is considering hiring a company to capture new LiDAR data to help with current stormwater issues that we are currently experiencing. I am a GIS analyst that has been assigned with this ...
9
votes
3answers
4k views

Filtering out canopies and buildings from DSM to have a bare earth elevation

Can anyone suggest methods in filtering out trees and buildings from a DSM so as to come up with a reliable DEM? What I have is a grid from a LIDAR data (.tif file, with 1m resolution). I was going ...
9
votes
4answers
2k views

How to distinguish buildings from vegetation in LIDAR data?

In order to extract the vegetation mask in ecognition, with object base analysis, with creation of the rule sets, the buildings were also classified! Any idea how to extract building from vegetation? ...
9
votes
1answer
748 views

Explaining laser scanning distortions on water surfaces?

I have received tif Laserscan images interpolated from Ascii data. I did not process the data so cannot say which processes or tools were used to interpolate the data. There are strange distortions on ...
9
votes
1answer
3k 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 ...
9
votes
2answers
678 views

Practical Building Extraction Algorithm Implementation

I've been reading many papers over 3D building extraction using LiDAR data and Aerial images. I see that there are many different algorithms for doing such things, such as this and this. Those papers,...
9
votes
2answers
315 views

Identifying Joshua trees with LiDAR data?

I'm working on a LiDAR project to determine where Joshua trees are located within a specified study area. Due to the vegetation cover being so sparse, there are really on 2 canopy species there, which ...
9
votes
0answers
495 views

Seeking open raw LiDAR or laser scanner data? [duplicate]

I'm looking for aerial LiDAR or terrestrial laser scanner data in laz or las format preferably from an FTP site. Does anyone know which countries have that data available to the public? From my ...
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. ...
8
votes
3answers
4k views

Do any open-source .Net libraries (commercially usable) exist for reading/writing LiDAR data?

I have a few LiDAR point data (.las files) with me. I would like to read the X,Y and Z from it using .Net. I found liblas, which is in C++ and I am not sure if it can be used commercially after ...
8
votes
3answers
4k 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 ...
8
votes
1answer
1k views

How to install PDAL in Windows?

I want to import .las files to PostGIS. As I found out I can do it by using PDAL. However, I cannot find the right way to install it in Windows. I downloaded a folder from here https://www.pdal.io/...
8
votes
1answer
1k views

River boundary (bank) extraction from LiDAR

Is there any way to extract a river boundary (bank) from LiDAR data and its products (DEM, intensity image and slope) automatically? Digitizing is very time consuming.
8
votes
2answers
381 views

Aerial LiDAR: What is an acceptable resolution?

I am in the process of initiating a project involving laser scanning. The area to be scanned i s approximately 5000 km². We are initially going to use the data to create a solar potential application, ...
7
votes
5answers
15k views

Converting LiDAR data to raster (DEM/DSM) for ArcGIS input?

I was wondering if there is an option to convert LiDAR data (.las) to a raster/grid (DEM/DSM) format that ArcGIS 10.0 can read?