Convert point cloud in xyz (ECEF) space to UTM

[Theodore Barnhart]

Hello everyone,

I am pretty new to the lidar world and am working on a change detection project in the Arctic using high frequency ground based lidar data. I get much better results when I use xyz coordinates in earth centered earth fixed space to georeference my point clouds. However, I have been told that Polyworks, which I am planning to use for my analysis, works better in UTM space. Does anyone know of a tool to convert a point cloud from xyz (ECEF) coordinates to UTM coordinates?

Thank you for your help!

Theo Barnhart
Graduate Student
Idaho State University

[Howard Butler]

On Nov 3, 2011, at 10:49 AM, Theodore Barnhart wrote:

> Hello everyone,
>
> I am pretty new to the lidar world and am working on a change detection project in the Arctic using high frequency ground based lidar data. I get much better results when I use xyz coordinates in earth centered earth fixed space to georeference my point clouds. However, I have been told that Polyworks, which I am planning to use for my analysis, works better in UTM space. Does anyone know of a tool to convert a point cloud from xyz (ECEF) coordinates to UTM coordinates?

GDAL, and therefore libLAS, has limited support for some ECEF coordinate systems. GDAL linkage might be one of the only things that libLAS does that LAStools doesn't these days :)

Using libLAS' las2las:

$ las2las -i input.las -o output.las --a_srs EPSG:ECEF-EPSG-CODE --t_srs EPSG:26918

Find ECEF-EPSG-CODE by looking at http://spatialreference.org for candidates if your LAS file does not have GeoTIFF keys to define the coordinate system of the file. If your file does have coordinate info already, eliminate the --a_srs entry in the command line.

Howard

[Jonas Lassen Jensen]

Hi,
Have a look at the "las2las"-tool. I have done some of change of
projection and assume that it will work for you to.

Find readme-file here on how to use:
http://www.cs.unc.edu/~isenburg/lastools/download/las2las_README.txt

Kind regards
Jonas

[Doug_N...@fws.gov]

You might want to check wit Frank Warmerdam at the GDAL / liblas projects.


http://lists.osgeo.org/pipermail/liblas-devel/2011-March/001283.html


Doug Newcomb            
USFWS
Raleigh, NC
919-856-4520 ext. 14 doug_n...@fws.gov
---------------------------------------------------------------------------------------------------------
The opinions I express are my own and are not representative of the official policy of the U.S.Fish and Wildlife Service or Dept. of the Interior.   Life is too short for undocumented, proprietary data formats.

ymg <ym...@hotmail.com> Sent by: last...@googlegroups.com 08/26/2012 04:41 AM Please respond to last...@googlegroups.com

To last...@googlegroups.com cc Subject [LAStools] Re: Convert point cloud in xyz (ECEF) space to UTM

I know it is an old thread but cs2cs from Osgeo actually Proj4 will do it.

However if you use EPSG code it will not work.

Here is proper command :

cs2cs  +proj=geocent +datum=WGS84 +units=m +no_defs +to   +init=epsg:4326 -f "%.8f"   input.txt > output.txt Just remember that EPSG:4978 that should be the code for an ECEF aka Geocentric system does not work, but by issuing the command as above you will get your CRS transformed.   Do take in account that Z coordinates will be on the ellipsoid. ymg

On Thursday, November 3, 2011 11:49:25 AM UTC-4, Theodore Barnhart wrote:
Hello everyone,

I am pretty new to the lidar world and am working on a change detection project in the Arctic using high frequency ground based lidar data. I get much better results when I use xyz coordinates in earth centered earth fixed space to georeference my point clouds. However, I have been told that Polyworks, which I am planning to use for my analysis, works better in UTM space. Does anyone know of a tool to convert a point cloud from xyz (ECEF) coordinates to UTM coordinates?

Thank you for your help!

Theo Barnhart
Graduate Student
Idaho State University

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