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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2
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1answer
512 views

Creating 3D polygon roof from LiDAR data using FME?

I have LiDAR data of a building and would like to construct a 3D Model using FME 2016. The LiDAR data shows that the structure has sloped roofs with various other elements on the roof surface (e.g. ...
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0answers
60 views

Error reprojecting point cloud with liblas 1.8: “latitude or longitude exceeded limits”? [duplicate]

I was previously reprojecting a point cloud in .las format using liblas 1.7.0 (with GeoTIFF 1.4.0 GDAL 1.10.1) as follows: las2las /tmp/input.las --a_srs EPSG:4326 --t_srs EPSG:3857 --scale 0.001 0....
4
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1answer
221 views

Is the ground level cross section of a normalised lidar dataset flat? [duplicate]

If I normalise a lidar dataset I am (according to my thinking) simply subtracting the first return heights from the ground heights. Thus the resulting dataset will only contains the height above ...
0
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1answer
504 views

Normalizing a digital surface model? [closed]

I am trying to generate a normalized DSM by subtracting the original DSM (oDSM) from the DTM. To generate the DTM I had to first use a median filter on the oDSM (remove noise) and then use a ...
2
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1answer
119 views

Elevation contours from .JP2 / .J2W files?

Is there a way in ArcGIS, Global Mapper, or CAD to generate elevation contours or any sort of surface data from a .JP2 file? I've never been provided this format before and our client is telling us ...
1
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1answer
123 views

How much do leaves on/off affect the number of LiDAR ground returns?

We would like to collect a generic purpose topographic LiDAR dataset over a large region in Belgium. Our minimum requirement is to achieve at least 1 point/m² on the ground. Ideally, we would like to ...
6
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1answer
169 views

Lidar DEM produces odd results related to topographic aspect

Background: ArcGIS Desktop 10.5.1, Spatial analyst We have acquired two bare-earth DEMs derived from lidar. YEAR2007 was produced in 2007, and YEAR2015 eight years later. Both are 32-bit, floating-...
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0answers
54 views

Fill gaps in dem created from .laz file [duplicate]

I've been trying to fill those lidar scan lines in my dem with no avail. Is there any way to interpolate those "gaps" to get a clean dem? I used las2dem to create the dem from .laz file
2
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1answer
565 views

How to write multiple .las files from polygon clipping with PDAL?

I am using PDAL (through Python) to crop multiple polygons from a point cloud and store them as separate files. For efficiency reasons I would like to define this in a single pipeline. However, using ...
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2answers
329 views

Merging LiDAR tiles without losing data in QGIS?

I'm trying to merge some LiDAR tiles together but when I do, the clarity of the image drops, so I think that means I am losing some data. How do I merge the tiles and keep all of the data and the ...
7
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2answers
187 views

Prevent SAGA in QGIS 3.0 from creating certain outputs?

I'm wondering if there is a way to prevent SAGA from generating temporary files. For example, if I just want to generate a slope map using SAGA I have to wait for all 11 other grids to get processed. ...
4
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1answer
188 views

Importing multiple .asc files into PostGIS violates check constraint. Why?

I am importing thousands of .asc files into PostGIS into this table: CREATE TABLE stg.COUNTRY_1M(rid serial primary key, rast raster); CREATE INDEX ON stg.COUNTRY_1M USING gist (st_convexhull(rast)); ...
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2answers
73 views

Locate LAS Points By Proximity gives ERROR 999999?

I am trying to locate LAS points which is within a specific distance (25cm or 50cm) from the 3D points in a feature class. This is exactly what the Locate LAS Points By Proximity tool should do. My ...
2
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1answer
543 views

Converting DEM to LAS file? [duplicate]

Is there a way to convert a DEM raster to a .las file using open source software and/or any tools that come along with a complete ESRI license? I have been able to achieve this using the LAS Toolset ...
2
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1answer
751 views

How to import raster (.asc) data to PostGIS?

I am using Postgres 10.3 / Postgis 2.4.2, and I have thousands of ".asc" files (LiDAR DTM/DSM files) to import to the db. However, the format is something like: ncols 1000 nrows 1000 xllcorner ...
3
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1answer
194 views

Extracting only elevation data from NASA's GLAS Satellite LiDAR to create raster DEM?

I'm trying to open data downloaded from NASA's Earthdata site in ArcGIS 10.4.1. Specifically I'm trying to open "GLAS/ICESat L2 Global Land Surface Altimetry Data (HDF5) V034" (Image below, ...
5
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1answer
138 views

How to assign (or project) CRS to LiDAR file in lidR?

Can someone enlighten me if there is a difference between initializing a CRS object using the EPSG code versus just the +proj string read from a shapefile? Consider the following objects: A ...
2
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2answers
226 views

GRASS r.in.lidar (las to raster) inside Python loop?

I have a loop in Python to list out LAS files in a folder, and run two commands in Grass GIS on these files to write them out as rasters. The loop runs but at the end I get an arg must be string not ...
3
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2answers
534 views

Clipping object of class LAS with polygon shapefile using lidR?

I want to make a simple clip with my .las 3D-Pointcloud. Therefor I use the lasclip() function. Import .las: lidar <- readLAS("~/data.las") lidar gives me class : LAS (LASF v1.2) memory ...
1
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1answer
120 views

Batch processing LiDAR files (.las to raster) with PyQGIS?

for layers in glob.glob("*.las"): processing.runalg("grass7:r.in.lidar", "input_las",5,1,"",1,100,"","",5,"","",False,True,True,"331289.57265,337990.42735,4558790.0,4560890.0",0,layers+"E:/...
6
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1answer
2k views

numpy array to GTiff using rasterio without source raster

I have a numpy array that represents rasterized data from a LiDAR point cloud. For example: import numpy as np import rasterio arr = np.random.randint(5, size = (100, 100)) I know information about ...
0
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1answer
111 views

Batch scripting r.in.lidar in pyQGIS for LiDAR DEM output? [duplicate]

I need to use pyQGIS to write a script that will run the r.in.lidar GRASS 7 on a set of LAS files. I am terrible at Python, but I need this for my task. I would like to process as a batch. How can I ...
0
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1answer
57 views

access r.in.lidar through pyGIS console [duplicate]

How can I access the r.in.lidar algo with the pyqgis console? i tried to import processing and algolist but r.in.liad under the GRASS GIS algo does not get listed. Also Checked the options iunder ...
5
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1answer
374 views

Georeferencing terrestrial LiDAR point cloud?

Recently I took a Faro Focus terrestrial laser scanner to a forested area and collected multiple scans for 12 fixed radius plots. Each plot had 5 GPS points collected within it in hopes to ...
2
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2answers
67 views

Correcting merged LiDAR DEM with outliers in inner edges?

I've created a DEM from LiDAR data. After combining all the files, I could see that there are some problems through the tile borders. This is an screen focused in one of the cross section of 4 files ...
2
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2answers
137 views

Why such a large difference between overlapping LiDAR DEM values?

Background: Using Arc Desktop 10.5.1, I have been tasked with mosaicking two adjacent LiDAR rasters (I'll call them A and B). They were flown, processed and supplied under contract by different ...
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0answers
135 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 ...
2
votes
1answer
177 views

Preventing interpolation outside of data extent with LAS Dataset To Raster ArcMap?

When I use the LAS Dataset To Raster tool in ArcMap I get an unwanted interpolation outside of the actual study area, like this: According to Esri this can be prevented by changing the definition of ...
5
votes
1answer
173 views

Fixing spikes in DSM from LiDAR?

I have a DSM derived from drone LiDAR that I want to use as a base to drape imagery and, paired with a DTM, as a basis for estimating canopy height/volume. Unfortunately, the DSM has has many "spikes"...
1
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1answer
256 views

Visualizing LAS with matplotlib

I'm trying to create a 3D scatterplot using an las file that contains xyz and return values. I want to keep all returns but would like to subset the cloud. I've learned how to subset using laspy so no ...
3
votes
1answer
269 views

Displaying LiDAR data with too many points in ArcMap?

I have imported LiDAR data into ArcMap in the shape of a Las DataSet with twelve .las files (contains over 100 million data points). I believe the file itself is working properly. However, no points ...
5
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1answer
381 views

GRASS's r.in.lidar error in QGIS 3: “North must be north of South”

I have LAZ files that I unpacked with laszip.exe, then I ended up with LAS files. These files showed no error when making a LAS dataset in ArcGIS. I used this dataset several times without ant issues....
0
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1answer
237 views

Locating outliers in LAS Dataset with ArcGIS?

According to the statistics and symbology of my LASD I have outliers. See below: How can I locate them in ArcGIS 10.x and do further analysis with them? I cannot query the dataset or select point? So ...
4
votes
1answer
154 views

Setting GroundFilter parameters for low density point clouds?

I'd like to use the function GroundFilter on my dataset. However, the manual says that the default values of the parameters used by this function (g parameter, w parameter) are related to a high ...
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0answers
183 views

Visualizing LiDAR data in a detailed footprint of rooftops with ArcGIS [closed]

For the last couple of weeks, I have been doing a research for making a detailed footprint with LiDAR data. The detailed footprint is needed for visualizing a 3D model. With a detailed footprint I ...
7
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2answers
5k views

Installing LAStools in QGIS 3.0?

I don't know how to install LAStools in QGIS 3.0. In QGIS 2.18, you can incorporate it as a provider in Processing -> Options-> Tools for LiDAR data (for example: Installing LAStools in QGIS 2.4?). ...
4
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1answer
248 views

Cropping raster and merge it to overlapping DEM?

I am working with an existing DEM of a river and its surrounding area in QGIS (actually a virtual raster from four separate DEM TIF tiles). My goal is to add a bridge's profile to the DEM. I have a ...
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0answers
92 views

Rice Field Levee Contours - .2 foot interval needed - LiDAR data? [closed]

I am a rice farmer in Arkansas and would like to create levees along contour lines in a field at a .2 foot interval. How could I utilize LiDAR data to map 0.2 foot contour intervals across my area of ...
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0answers
159 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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2answers
1k views

laspy ValueError: buffer size must be a multiple of element size

I am trying to learn LASPY and am running into road blocks off the bat. I first ran into and Error 8 (Not enough storage is available to process this command) using my full sized LAS file (1.7GB). I ...
1
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1answer
120 views

Which QGIS installation for Windows comes with r.in.lidar?

I am running QGIS 2.18.14 (QGIS code revision: ff83b9a479) on a windows 7 machine, it comes with GRASS 7.2.2 (Code Revision r71496), but it does not come with r.in.lidar. I have noticed QGIS 2.18.16.1 ...
2
votes
1answer
41 views

How does MERIS collect vegetation height data?

In GlobCover 2005 and 2009 project, the sensor used for spectral data collection was MEdium Resolution Imaging Spectrometer (MERIS). It observes the Earth in 15 spectral bands in visible and near ...
10
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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 ...
4
votes
2answers
343 views

How to filter point cloud by flightline in R?

The lidR package in R provides a way to mark individual points in a point cloud with a flightline ID by using lasflightline(). From the documentation: Retrieve each individual flightline by ...
2
votes
1answer
103 views

How to incorporate stdmetrics in gridmetrics function?

I am attempting to feed the lidR gridmetrics function a list of metrics. I can generate the list of metrics within a function (following this example): myMetrics = function(z, i) { metrics = list( ...
1
vote
1answer
148 views

Classify LAS By Height tool is not yielding any results?

The classify LAS by height tool (CLHT) in ArcGIS says that it will only reclassify LAS points with class codes of 0 or 1 (http://pro.arcgis.com/en/pro-app/tool-reference/3d-analyst/classify-las-by-...
1
vote
2answers
107 views

Getting statistics in cross sections at varying heights in LAS files?

I am looking to cross section my forest at varying heights. I have high return LAS data (8 points/m2 and average point spacing of 0.2m) and I am looking to do more than the simple 1, 2, 3 approach of ...
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0answers
89 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 ...
3
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1answer
554 views

error: Compression support not enabled in liblas configuration

I am using liblas 1.8.1 and laszip 3.1.1 on Mac OS High Sierra. Both were installed using brew install <package>. I am looking to get information from a laz file using the following command: ...
4
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3answers
632 views

Open source approach to classifying and removing LiDAR points from overlapping scans?

The attached screenshot shows a LiDAR point cloud with significant overlapping scans. This point cloud tile is part of the MN statewide LiDAR dataset which has 25% scan overlap and 1.5 NPS. For many ...