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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Masking LiDAR points to create DEM in ArcGIS Pro with ArcPy?

I have an irregular LiDAR point cloud dataset, so when I try to create a DEM or DSM, the points are connected across the irregular edges of the LiDAR point cloud. I thought that creating a mask ...
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52 views

Checking and enforcing downstream Z constraint for synthetic streams?

Assume I've delineated planar (X, Y) stream breaklines to use them for enforcement of bare ground DEM derivation from high density lidar data. The stream features are in a Z and M enabled polyline ...
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116 views

LasDatasetToRaster does nothing to the Raster Layer

I have been trying to figure out how to clip and rasterize a LiDAR map file programmatically (Not through arcpy) I use C# but read many languages. So far I have been able to access and assign the LASD ...
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64 views

Importing several LiDAR (.las) files in GRASS using v.in.lidar?

I'm building a DEM of a terrain in GRASS and have 48 LiDAR (.las) files. I know I can do this by using r.in.lidar (including the list of files as a .txt) and then r.fillnulls However, I want to ...
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55 views

Speckle on LiDAR data

Does LiDAR data suffer from the speckle noise like the SAR images and ultrasound cardiac images I'm used to? I think speckle noise is inherent to all active sensors, but I'm not sure for LiDAR ...
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66 views

Parallel optimization for query over LiDAR dataset

I'm using PostGIS + pointcloud to store a huge dataset of LiDAR point (2M patches of 600points) I query this database to obtain the altimetic profile between two points. At the moment I have a huge ...
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256 views

Dynamically styling LiDAR data in QGIS?

I am using QGIS 2.18.4 on Windows. I have LiDAR data in GeoTiff format. Is there a way to dynamically style the GeoTiff layer based on the current map extent? I need to re-style the GeoTiff layer ...
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90 views

Finding specific area with coordinates out of a lot of LAS data?

I would like to extract spatial data out of a great amount of LAS data. Unfortunately, there is no index or sth that could help me find which file is for what area. Also, it is not possible to ...
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104 views

Opengeo and Ubuntu memory issue

I was working with LiDAR in Opengeo suite while following the Boundless tutorials (http://workshops.boundlessgeo.com/tutorial-lidar/) In my recent post titled 'LiDAR and Opengeo', I mentioned about ...
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379 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 ...
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19 views

Stacking lidar-derived height raster as ancillary data for segmentation in ENVI?

I get a a black and white image after following these steps. Does anyone know why I'm not getting a color aerial image beneath the mask? My setup consists of these steps: I mosaicked several NAIP ...
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72 views

How to georeference point cloud data that was no spatial information?

I'm working on a project right now that the final goal is to compare two DTMs of a glacier surface from different years to visualize the change over time of the glacial surface. The first DTM was ...
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34 views

Creating Left and Right Image pair to view with 3D goggles in stereo from DEM or Hillshade?

How does one create the stereo pair for viewing in a program such as StereoPhoto Maker? I have processed lidar that I'd like to turn into hillshades and then view in this kind of software, with 3D ...
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131 views

Create laspy file object without creating a new file

I would like to create a new laspy.file.File object in memory without having to create a reference .las file. The basic procedure is read sample.las clip sample.las by converting the x and y ...
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154 views

FUSION's PolyClipData creates corrupt LAS file?

I am trying to learn LASPY and am following a tutorial. I got an error when starting up using: import laspy infile = laspy.file.File("./laspytest/data/simple.las", mode="r") where I got a storage ...
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87 views

Completing Coordinate transformation?

I have two airborne lidar datasets and, for purposes of comparing change between the two, would like to standardize the vertical and horizontal coordinate information for each. The plan is to ...
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52 views

How to diagnose an “invalid data” error message using the r.sun GRASS tool?

I'm using the r.sun GRASS tool to map solar inputs and shade or lack of it in Pacific NW salmon streams. I clipped out the input raster data (a canopy height model, aspect, slope) for a 15 hectares ...
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80 views

How to extract and export “raised field” LIDAR objects?

I'm working on Windows 10. In input, I have a .LAS "GROUND_only" LIDAR point cloud (4 millions points). We're interested in geomorphological microstructures called raised field (ground elevation due ...
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76 views

Running Python script in GRASS every time map extent is altered

I am looking to develop a python script that triggers every time the user zooms or pans to a new map extent. The script I have in mind will clip a raster to the visible extent thus reclassifying the ...
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159 views

Building vectors in polylines

I have classified the cloud points of LiDAR data into different classes. After extracting I have generated 3d building polygons using "Vectorize buildings" option from terrascan tools. Now I need to ...
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117 views

Update EVLR header info for very large LAS files using laspy

I ran into another problem when applying my workaround to large LAS files. The issue is noted at the github page for laspy here: https://github.com/grantbrown/laspy/issues/51 This builds on an earlier ...
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234 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 ...
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189 views

TIF not showing UTM coordinates in world file

I have a lot of tif files (ortho imagery that came with Lidar data). Each tile has a .tif and .tfw but the world files (.tfw) have line 5 and 6 as numbers that aren't what I would expect as I was ...
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261 views

Converting raster to TIN in ArcMap 10.1 is causing crashes?

I have several tiles (~200) of Lidar 1m resolution data from Geomatics group and need to convert it to TIN format (currently in .asc) to develop a flood model. Is there a quicker way of doing this ...
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113 views

Using GPS to field walk through a LiDAR scene

I am doing field surveying for archaeology using Lidar. If I attached a USB GPS to my laptop would it be possible to track where I am "in real time" on the Lidar as I am field walking? I'm wanting to ...
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490 views

How to increase FUSION-LTK lidar processing productivity?

I am processing Lidar data with FUSION-LTK. My study area contains 5 blocks of 1000 las tiles per block. Each block is broken into approximately 4 subblocks of 250 las tiles. I am calculating grid ...
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27 views

LiDAR from WMS?

For my project, I must use LiDAR to generate 3D profile of terrain structures. I downloaded a 2m LiDAR WMS composite digital surface model available here: https://environment.data.gov.uk/spatialdata/...
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7 views

Adding RGB values from a .txt file to a .las file using laspy

I have a text file that has XYZ and RGB values in it. To convert it to .las format i use lfile = laspy.file.File(r"D:\las\tolas.las", mode='w',header=LasHeader(x_scale=0.01,y_scale=0.01,z_scale=0.01))...
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98 views

Timestamp mismatch in the data recorded by Vlp16 with Ublox-M8T

Currently, I am working on Velodyne vlp16, for which I recently added UbloxEVK-M8T support. The setup is working fine but when I record the data from VeloView, the GPS timestamp is showing incorrect ...