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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6
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2answers
2k views

Python script using SAGA and arcpy for converting 'on the fly' LAS point cloud to shapefile?

Summary: I have created a process to import a LAS point cloud, clip it, select the ground points and save the output as an XYZ.txt for clients to use. This uses a python based script (will become a ...
4
votes
2answers
212 views

Lightweight python modules to convert LAS data formats to text formats?

I searched on the net and found pyLAS, but it seems to require quite a few other modules and I couldn't get the install right. Any pointers will be much appreciated.
2
votes
2answers
130 views

Using python to batch process lasclip - LAStools/QGIS

I am trying to use the python console to batch quite a few processes from lastools. I'm having trouble with the arguments to lasclip. clipped_las = processing.runalg('lidartools:lasclip', True, ...
2
votes
1answer
51 views

Finding the origin in .laz file with LAStools

I obtained a .laz file, which I used lasinfo and las2txt to view the records. Scale Factor X Y Z: 0.00100000000000 0.00100000000000 0.00100000000000 Offset X Y Z: ...
4
votes
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 ...
1
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1answer
31 views

LAStools blast2dem: error writing data for field “StripOffsets”

I was processing an overage file to generate DTM and DSM using blast2dem. The generated DTM file can be viewed using ArcMap and ENVI. However, ArcMap and ENVI cannot open the generated DSM file. I ...
4
votes
2answers
187 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 ...
3
votes
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 ...
1
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1answer
58 views

Extracting above ground features from unclassified LAS [closed]

What's the best way to vectorize features from LAS? I have "Classified" LAS files, however they were never processed for classification. Thus of 181 million points (9 tile sample) about 60% are class ...
2
votes
1answer
398 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
38 views

How to specify LAS dataset filters in ArcMap ModelBuilder?

I'm trying to create a tool in the ArcMap ModelBuilder to extract a canopy height raster from LiDAR data. I need to create rasters for ground elevation and first return. I've got my LAS dataset, and ...
5
votes
1answer
381 views

Reprojecting LiDAR data with libLAS

I have a lidar file (file.las) with the following spatial reference: Spatial Reference: PROJCS["NAD83 / UTM zone 11N", GEOGCS["NAD83", DATUM["North_American_Datum_1983", ...
0
votes
1answer
89 views

LAStools (3D Analyst) scale factor application

I'm trying to use the las2las (transform) module from the LASTools toolset to apply a scale factor to an LAS dataset. The problem is that the client wants us to apply the scale factor from a known XY ...
2
votes
1answer
117 views

How to remove las2dem streaks from raster DEM?

I've created a series of DEM files using the las2dem tool from LAStools; however since I don't have a licensed version they have black streaks running across them. Does anyone know a good method for ...
5
votes
4answers
1k 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 ...
3
votes
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 ...
1
vote
3answers
193 views

Classifying individual trees from labelled LiDAR point cloud [duplicate]

I have a classified point cloud for an area of 250*250 square meter, with 1 meter resolution. It has a 5 lakhs points with an average point density of 9 (means around 9 points within a pixel). I ...
4
votes
5answers
2k 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 ...
3
votes
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. ...
1
vote
3answers
342 views

Open LiDAR DEM of the UK with *.asc extension

I've downloaded a tile of a freely accessible LiDAR DEM of the UK from http://environment.data.gov.uk/ds/survey#/download. But I don't know how to open it. The files inside have the *.asc extension. ...
3
votes
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 ...
2
votes
1answer
72 views

Extract manhole covers from ground LiDAR

I am wondering if anyone has come up with an automated or semi-automated workflow for extracting manhole covers from LiDAR data in ArcGIS? I was thinking about looking at the change in elevation ...
4
votes
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 ...
2
votes
0answers
352 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 ...
4
votes
1answer
2k 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: ...
2
votes
0answers
45 views

Reference file paths stored as attributes in Model Builder

I'm trying to design a model in Model Builder that will derive input files for a process from file paths stored in an index shapefile's attribute field. The two datasets involved are a shapefile ...
2
votes
1answer
73 views

Creating a Terrain from a Multipoint file if the “New Terrain Wizard” is missing?

I created a multipoint file using the tool LAS to Multipoint in ArcMap. After it was done processing, I went to my geodatabase, right-clicked and attempted to create a terrain. However, the wizard ...
1
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0answers
34 views

Creating a reference line among LiDAR points and retrieving distances between them?

I have a LAS dataset which contains points with x and y coordinates. For further analysis I need a new dimension which can be adjusted as the dataset requires. To make it understandable I made this ...
2
votes
1answer
64 views

Merging more than 9 input files with lasmerge?

Is there a possibility to feed more than 9 LAS files to lasmerge tool? The user interface only allows 9 LAS files from LAStools toolboxes in QGIS or ArcGIS, but at liblas.org it’s described as there ...
1
vote
1answer
55 views

ArcScene can't symbolize LAS points by classification code or number of return

I'm using ArcScene 10.3 and loaded a LAS file into a LAS Dataset. When I look at the LAS files statistics I can see that there are several classification codes and 7 different returns. Everything ...
2
votes
1answer
792 views

Converting LAS file to .asc DSM? [duplicate]

I want to count trees in SAGA GIS and I am trying to follow the steps described in Counting trees using segmentation and vectorization in SAGA Gis from dominoc925.blogspot.com (05th, March, 2012). ...
1
vote
0answers
73 views

Reduce Z value precision in QGIS

The .asc LiDAR files provided by the environment agency have height values provided to a precision of the level used to measure atoms. How to quickly lose a few of the pointless digits on the end to ...
2
votes
1answer
303 views

Reading las files with laspy [closed]

New to laspy and encountering an error. The first code block describes the file header, the second (In[24]) fails to open the file with laspy: In [21]: import numpy import laspy from laspy.file ...
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 ...
5
votes
2answers
146 views

Can LiDAR differentiate between rock and soil?

Can LIDAR by itself, tell the difference between rock (large and small) and soil? I'm under the assumption that the answer is no. However, I wanted to check here with the experts as I was told by ...
3
votes
0answers
146 views

Converting LIDAR based measurement to UTM coordinate?

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 ...
2
votes
1answer
172 views

Filtering noise out from bare-earth DEM with terrace fields?

I have a 1m bare-earth DEM, derived from LiDAR data, representing a terraced landscape. For the sake of any subsequent use of the DEM (e.g., least-cost path, cost surface analysis, and the like) I am ...
0
votes
1answer
30 views

Fixing Pixelation in DSM [duplicate]

I ran las dataset, then las to raster using max for DSM. Two and a half hours later I have 3 areas showing pixilation using higher level coloring. See enclosed image. I found on web that seamless ...
5
votes
3answers
2k views

Determining bare earth 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 to create my DTM from the DSM. I have tried SAGA, ...
0
votes
0answers
13 views

How to classify a LAS file into ground points and vegetation [duplicate]

I have a dense LiDAR point cloud in .LAS format for a forest. All the points are unclassified. Just wondering how to manually classify the points into ground points and vegetation. I noticed that a ...
1
vote
2answers
82 views

PDAL: Couldn't create filter stage of type 'filters.voxelgrid'

I have the following PDAL pipeline: <?xml version="1.0" encoding="UTF-8" standalone="no"?> <Pipeline version="1.0"> <Writer type="writers.pgpointcloud"> <Option ...
3
votes
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 ...
2
votes
1answer
78 views

Creating multiple LAS datasets from LiDAR files in various directories using model builder?

I have 60 folders each containing approximately 20 LiDAR files in .las format. I want to create one LAS dataset from .las files from each folder, and each LAS dataset is named by the folder name. I ...
3
votes
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?
-2
votes
1answer
60 views

Expression into the raster calculator to invert DEM

I've made a DEM from first pass LiDAR data which I want to invert and run watershed segmentation and basin delineation over in order to hopefully extract tree canopy outlines and heights - I'm newish ...
1
vote
1answer
39 views

Leica Cyclone 5.1 TLS Data referencing using Trimble DGPS

I am using a Leica HDS3000 Terrestrial Laser Scanner (TLS) and Cyclone version 5.1 to acquire and process point clouds. Within the manual for Cyclone 5.1, Leica mentions that a user can enter the ...
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 ...
7
votes
4answers
1k 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
10answers
13k views

Where can I get pointcloud 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. Edit: I've found that these pages ...
0
votes
1answer
87 views

How to find the height information from LiDAR point cloud data [duplicate]

I need to find the biophysical parameters(biomass) from the LiDAR point cloud data. For that I need the height of the trees from the data. Currently I am having the general height with respect to sea ...