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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5
votes
1answer
2k views

How to create contours from smoothed DEM instead of using Terrain to Raster?

I'm fairly new to working with lidar and have been assigned the task of creating 2ft contours for the entire county using USGS-provided lidar tiles. Is there a significant difference in the accuracy ...
7
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2answers
2k views

How to de-noise a DSM?

I have created a DEM, DSM, and nDSM from a LiDAR Point Cloud using SAGA-GIS. I extracted the appropriate returns from the point cloud, then converted to grid, and then closed gaps to fill in any ...
3
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1answer
331 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 ...
4
votes
1answer
739 views

How to add points to LAS copy using liblas?

I am trying to make a copy of a LAS file while inserting new points using python liblas module. The code below creates the copy and adds the points, but for some reason the added points are not in ...
20
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9answers
18k 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 ...
3
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0answers
320 views

Converting LIDAR based measurement to UTM coordinate? [closed]

I have lidar based measurement with azimuth elevation and range, I would like to convert this data to UTM coordinate. I know the position of the lidar in UTM coordinate system, so I developed the ...
4
votes
1answer
342 views

How do I use a DHM in tiff format for distance and slope measurements?

I am a student and I have to work out a project about soil loss on a plot. I need basic measurements of this plot such as length, width, area and slope for my erosion calculations. I have got my ...
1
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0answers
68 views

LiDAR Basics - How classes are determined at LiDAR data? [duplicate]

LiDAR data have classes as Medium vegetation, Buildings, Ground, Model Key and more. What determines these classes ? is it combination of intensity and scan angle rank ? how to reclassify these ...
1
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1answer
388 views

How to add LiDAR Intensity attribute to a point feature class?

I need to convert LASD (ESRI LAS Dataset) to ASCII text file. I've export the data to point feature class (LAS to Multipoint), converted multipart to single part and calculate X Y and Z.My first ...
3
votes
3answers
2k 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 ...
15
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3answers
6k 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 (...
2
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1answer
1k views

Load LAS files in MapInfo

Is it possible to open LAS files within MapInfo? If so, how is accomplished in MapInfo 10.0?
7
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1answer
1k views

Looking for free / open source Lidar web viewer?

I have lidar data which I want deploy my users using web viewer. I will probably hold the data in PostGIS (not sure yet). Is there good open source/free lidar viewer that I can integrate with ...
3
votes
1answer
807 views

How to compare accuracy of two DEM using GRASS

How do I compare accuracy of two DEM data (lidar and srtm) (possibly through rmse) using GRASS GIS?
1
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0answers
40 views

Removing coincident points with z values greater than minimum [duplicate]

I am trying to run a spline interpolation on some terrestrial LiDAR data, but it keeps failing (I'm getting error 010235 - returned error from spline process and error 010067 - error executing grid ...
1
vote
1answer
2k views

GDAL RasterIO grabbing memory

I have written an application in c++ to read LiDAR files and convert to various rasters using GDAL; this worked very well on small scale tests (47 LAS files) however, when used on a live task the ...
5
votes
1answer
453 views

LiDAR Feature extraction specifications/standards

I have vector data representing forests/trees/buildings that have been automatically extracted from LiDAR data. I am looking for specification/guidance for LiDAR derived products, or any standard for ...
0
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1answer
4k views

Is it possible to load an .las file directly into QGIS? [duplicate]

Is it possible to load an .las file directly into QGIS? I would like to be able to load LiDAR data and to be able to do analysis based various feature attributes; e.g., elevation, classifications, ...
5
votes
1answer
2k views

What is the procedure to load LAS files in QGIS 2.0.1?

What is the present procedure to load LAS files in QGIS 2.0.1? After some searching I found a paper outlining the procedure; however, it was for 1.8.something, and related posts here are all rather ...
3
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3answers
5k views

Converting a .lasd (Lidar) coordinate system?

How can one change a coordinate system for a .lasd (Lidar) dataset? The file is currently in UTM_Zone_15N and I am trying to convert it to IL_East.
9
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2answers
724 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,...
4
votes
2answers
856 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, ...
2
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2answers
2k views

LAS sample file for electric utility poles

Does anybody know a souce where I can find a sample LAS file that has electric utility poles? Like seen here - http://resources.arcgis.com/en/help/main/10.1/index.html#//015w00000040000000
5
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2answers
794 views

Creating planes, eg roof surfaces, from LiDAR/DSM data

I am capturing the area of roof tops of buildings from a DSM (derived from LiDAR data) which has not been much of a problem. I can then also derive angle, hillshade and aspect but it is only per-pixel....
1
vote
1answer
2k views

Calculating median value of polygon from points in ArcGIS Desktop?

I have a point layer coming from LIDAR data containing x,y,z and intensity values. On the other hand I have a layer containing several polygons. All the points are inside the polygons. I need to ...
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2answers
7k views

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?
3
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2answers
2k views

Canopy Height Model of LiDAR data in QGIS?

I have a DTM and DSM files. I want to develop a Canopy Height Model (CHM) in QGIS. Is it possible?
2
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1answer
288 views

3D model of rooftops based on LiDAR and cadastral data?

I´m trying to model building rooftops based on a LiDAR dataset. I've already interpolated using Delaunay's triangulation a DEM with 1 meter resolution. Due to LiDAR data is not accurate in building ...
6
votes
1answer
764 views

Problem reprojecting LIDAR data with Liblas [duplicate]

I am currently trying to reproject a LIDAR file (.las) using the Open-Source LibLAS, compiled on a Scientific Linux server. The Original data is in Oregon Lambert, NAD83 (EPSG:2992), and I am trying ...
7
votes
1answer
233 views

Options for manually identifying road defects from Terrestrial Lidar

I am trying to create a process to identify road defects manually from Lidar. We have Erdas 2013, ArcGIS10.1 and Global Mappper 14.2 as options for paid software. So far Merrick Mars displays the ...
2
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0answers
382 views

Extract road defects from terrestrial LiDAR, in Erdas 2012 or ArcGIS10.1

I'd like to extract road defects from a lidar point cloud. So, wherever a road surface drops or raises by a few mm relative to 100 cm around it. I know it's possible but I just can't find or figure ...
6
votes
1answer
10k views

arcpy “The table name is invalid”

I wrote a script that, ideally, loads raw .las (LiDAR data) files into a geodatabase, then creates a terrain from the multipoint files that are created. When I run the script though I get: ...
11
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7answers
10k 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 ...
5
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3answers
7k views

How do I import UK Environment Agency Lidar data (.asc) into QGIS

I have downloaded Lidar data from the UK Environment Agency as ESRI ASCII files but being a complete novice as far as GIS is concerned I do not know how to view them. Quantum GIS was recommended to me ...
2
votes
1answer
537 views

Input data format and read multiple files into Grass 6.4.1

I am trying to read in multiple (hundreds, thousand) LiDAR ascii files into Grass. They contain elevation data. I think I have managed one, and I can make a map of elevations, using File, Import ...
3
votes
1answer
1k 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 ...
7
votes
1answer
322 views

How to decide possible areas for water retention using lidar

I have lidar imagery for a watershed and am trying to process it so that a landowner know if they can hold water on their property or where they can hole the water (this is the more important part). I'...
3
votes
1answer
532 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 memory;...
2
votes
1answer
790 views

Help with Parameters for MCC-LiDAR

I am attempting to use MCC-LiDAR to reclassify points (.las) originally classified using TIFFS. However, I seem to either be misunderstanding what the parameters really mean or where to get the ...
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. ...
2
votes
1answer
909 views

Problem importing LiDAR data in GRASS 7

I compiled GRASS 7 on Ubuntu 12.10, with liblas in order to run r.in.lidar and v.in.lidar. I now want to import .las data; the option in file -> import raster data -> LAS LIDAR points import is given ...
1
vote
1answer
452 views

Adding Feature Class to Terrain using ArcPy gives ERROR 000800? [closed]

I'm writing a script to convert lidar data (in .las format) into a terrain without going through all the clicking and so I can send it out to neighboring states with similar programs (I'm using ArcGIS ...
0
votes
1answer
273 views

Why does ArcGIS model not recognize Z value column?

My ArcGIS model used to handle .XYZ files well, but now it fails to recognize Z-value column as such - it either recognise no field at all, or it offers some defaults such as "OID". Since the last ...
5
votes
2answers
2k 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 ...
1
vote
1answer
700 views

How do I install the las2ogr tool from liblas in Windows using the osgeo4w installer?

I was wondering if anyone has used the LAS2OGR tool? I heard about this from a previous post. The webpage gives the usage: http://www.liblas.org/utilities/las2ogr.html las2ogr -i mydata.las -o ...
6
votes
3answers
2k views

Finding outliers with wrong Z values in LIDAR data

I have more than 2000 XYZ (only ground points) .txt files and I have to do Quality Control (QC). Let's say I have file, which I converted to multipoint (or even singlepart feature). I have mean Z ...
8
votes
3answers
7k views

Classifying LiDAR data with LAStools?

I am presently using LAStools to analyse LiDAR data. Can LAStools classify the points into various features such as vegetation, roads, buildings etc? If so, how is it done?
12
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2answers
2k 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 ...
3
votes
2answers
970 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 (non-...
1
vote
2answers
776 views

SAGA-GIS Produces different results in command line than GUI

I have been working on a lidar processing workflow using SAGA-GIS. I determined my workflow on a single tile in the SAGA GUI and now I need to batch the operations on 100 more tiles. I wrote a batch ...