Tagged Questions

LIDAR (Light 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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9
votes
4answers
901 views

comparing two DEMs

i have two Lidar las files, 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 wanted to compare how the Digital ...
2
votes
2answers
51 views

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

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 ...
0
votes
1answer
76 views

ArcGIS can't find Z value

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 ...
6
votes
1answer
286 views

Breakline detection algorithms for LIDAR dataset

I'm searching for algorithms or open source tools I could use to detect breaklines from a LIDAR dataset; more specifically, from the terrain points of the dataset. At the moment the only thing I've ...
5
votes
1answer
256 views

Floor height creation from Aerial Lidar/Imagery only

I was wondering if it is possible to generate the floor heights of buildings from aerial lidar? We don't have terrestrial lidar or stereo imagery. I don't need the ground DEM level or the roof (DSM) ...
4
votes
1answer
117 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 ...
0
votes
0answers
11 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 ...
7
votes
1answer
74 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). ...
9
votes
7answers
604 views

What is the best way 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 ...
3
votes
1answer
48 views

Problem with mcc-lidar

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: insuficient memory; ...
7
votes
2answers
182 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. ...
4
votes
3answers
151 views

Finding outliers with wrong Z values in LIDAR data

I have more than 2000 XYZ .txt files and I have to do QC: let's say I have file, which I converted to multipoint (or even singlepart feature). I have mean Z value for a file, but ... if most of the ...
2
votes
1answer
49 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 ...
6
votes
5answers
272 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?
6
votes
3answers
200 views

Can I use LASTools to classify point data?

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?
2
votes
5answers
1k views

How to convert LAS to GRID/Raster for ArcGIS input?

I was wondering if there is an option to convert LAS (LIDAR data) to raster or GRID format that ArcGIS could read it. Thanks.
1
vote
1answer
66 views

Grass 7 .las data import problem

I compiled Grass7 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 ...
10
votes
4answers
364 views

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 ...
7
votes
2answers
153 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, ...
3
votes
2answers
144 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 ...
8
votes
2answers
900 views

How do I combine 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 ...
11
votes
3answers
236 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 ...
6
votes
8answers
895 views

Where can I get pointcloud data?

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.
0
votes
0answers
60 views

arcpy Add Feature Class to Terrain error. LiDAR Processing Script

So here's another one for you ever so helpful StackExchangers (is that right?) Anyway, I'm writing a script to convert lidar data (in .las format) into a terrain without going through all the ...
2
votes
4answers
841 views

What are Limits on ArcScene and LiDAR?

I am trying to load anywhere from 5 to 10 LIDAR TINS into ArcScene. I am using ArcGIS Desktop Evaluation (student) 9.3.1. I just built a new computer with a AMD Phenom II X6 1090T six core processor, ...
4
votes
2answers
144 views

how to retrieve 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
0answers
146 views

QGIS 1.7.4 crashes when using interpolation tool

I am currently using QGIS with Lidar data to produce hillshade images. I have split the lidar data in 20 files (31kb). Some of the files are working some are not. I have checked the files xyz are ...
1
vote
0answers
22 views

ArcPublisher appears to be mirroring the ecw Lidar files on the southern axis of the file

ArcPublisher appears to be mirroring the ecw Lidar files on the southern axis of the file. Has anyone experience this? Is there a setting in ArcPublisher that I need to turn on or off? The way i ...
14
votes
13answers
15k views

How to a convert LiDAR XYZ files to DEM / DSM?

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 ...
13
votes
5answers
2k views

Best Software for LIDAR data?

I will be working with LIDAR data soon and have heard that ESRI Tools are not particularly well adapted to work with LIDAR Datasets. What are the best alternatives in your opinion? Which are ...
1
vote
1answer
50 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 ...
13
votes
6answers
3k 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 ...
1
vote
2answers
127 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 ...
1
vote
1answer
307 views

Are there any open source software for obtaining and processing data from the Velodyne HDL-32E lidar?

Does anybody know if a FOSS package exists? The best I could find are the scripts at binarymillenium. I was just hoping somebody here knows of a complete package for obtaining and processing the data. ...
1
vote
1answer
53 views

LASToMultiPoint_3d

Trying to use the arcgis python command LAStoMultipoint_3d as seen here. I'm running the code snippet against one of my LAS files. It creates a .shp, sbx, shp.xml, shx and dbf file. However, the ...
8
votes
3answers
946 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. ...
2
votes
1answer
101 views

Lidar Elevations Data

I am trying to acquire a method of detecting sub cm elevation without manually measuring from the field. Can LIDAR data produce this for me? Example: A 1500 foot long pipe conveying water from one ...
4
votes
2answers
741 views

How to build 3D building models from lidar data?

Aloha to all and thanks for helping me. I have Lidar data, ground points and first returns. I have processed it and have ready tiles from which I am trying to build 3D building models. So far I was ...
1
vote
3answers
193 views

How to create a generalized polygon layer from a raster?

I have a tiff file where I have extracted vegetation in a height interval from LIDAR. At the moment the picture is kind of blurry with no data cells between vegetated cells. I would like to create a ...
2
votes
0answers
263 views

Simulate flood to assess Asset inundation footprints

I am trying to evaluate a number of flood gauges to assess at what levels of river height different flood risks would need to be issued. The gauges are currently set to warn of flood a couple of ...
4
votes
3answers
331 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 ...
4
votes
1answer
910 views

Lidar - Automated building extraction (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? ...
2
votes
0answers
34 views

ESRI LasDatasetBuilder

Does anyone know of any working examples leveraging the new ESRI ArcGIS 10.1 Lidar classes i.e LasDataSet or LasBuilderclass? I've looked around on http://resources.arcgis.com/en/help/arcobjects-net/ ...
1
vote
1answer
310 views

Aligning coordinate systems: gpx, LiDAR, shapefile

I am working on a project based on a lidar data set (for use in LidarViewer in Linux, a basic x,y,z viewer) that was downloaded from #1 below at Opentopo.org and looking to add onto this data set with ...
10
votes
3answers
889 views

optimize nearest neighbor query on 70 million extremely high density spatial 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 ...
5
votes
2answers
295 views

Seeking commercial web service for LIDAR/DSM data in USA

I apologize for not knowing all the proper terminology to ask this question. I am seeking a commercial service for providing pay-per-use high resolution elevation data in North America. It must come ...
3
votes
2answers
225 views

Purpose of building footprints

What are the uses (public and private industry) of building footprints? I'm trying to figure out how polygon building footprints can be used. i.e. are they used for determining tax liabilities, ...
1
vote
2answers
268 views

Can REST or the ArcGIS API for Flex read VAT tables from a Raster?

When publishing a bare earth DEM that has a VAT table, or value attribute table "A VAT is a table containing attributes for a grid, including user-defined attributes, the values assigned to cells in ...
1
vote
3answers
287 views

Where can I find the highest resolution shapefiles for counties or states

I am looking for a download source which has the highest resolution (greatest detail/accuracy) for all counties in the US. More specifically I run into this problem mainly when dealing with the ...
1
vote
2answers
429 views

Mosaicing LIDAR files in ArcGIS 10

I have a number of LIDAR files (the extension is .adf). When put together, they show the same area (each shows one part of it), so, before I do anything else with them, I would like to combine them ...

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