LiDAR Coordinate System Datum

[cody_austin-origindesign]

I am trying to get publicly availible LiDAR information to translate to the correct Datum.  The data is in UTM NAD83 Zone 15 Metric.  I set the coordinate system for the information, and the point cloud database.  The data is inserted at the correct northing/easting, but the elevations are still in meters.  Is there a setting or step that I am missing?  Thank you.

[AllenJessup · Accepted solution]

If you're on subscription I'd suggest opening a support request. UTM NAD83 Zone 15 Metric and I presume that the datum your going to are both Horizontal Datums. I've heard that C3D will do vertical transformations but I've never seen it happen. I haven't used cloud data yet so I don't know if there is any way to specify the vertical datums.

What kind of file is the point cloud database? Could it be exported to an ASCII N,E,Z file. I always end up using Corpscon to translate a file - http://crunch.tec.army.mil/software/corpscon/corpscon.html

Allen

[cody_austin-origindesign]

Currently my workaround is to use Map3D and Query a metric drawing to the State Plane coordinate system.  The LiDAR points are .LAS or .XYZI

[Sinc]

If C3D can correctly translate the elevations, then it's a well-kept secret that I, too, am unaware of.

[AllenJessup]

Corpscon will work on an XYZ file. Just set it up as a user designed batch file. I know you files will be large but Corpscon is FAST. I've seen it fly through files of near 10,000 point in a second or two.

Allen

[riyach]

you will need to have a file with your all of your units set to meters and create your lidar surface.  then simply export your .xml to a new drawing that is set up to feet.  that should translate your vertical units to the feet.

sorry, but i've found this is the only way for me.  also it's worth mentioning I am using C3D 2009.

[Wilderman2]

I have recently found the .xml export is the only reliable method for transformations, both horizontal and vertical.  Portions of the coordinate system transforms work between C3D drawings, but do not appear to do so consistently.

[cody_austin-origindesign]

Any updates on this issue?

[AllenJessup]

I finally had to do this myself. The LAS files weren't in ASCII so I didn't have a point file to convert. What worked was to export the metric surface to a DEM file and use that to create a Surface in a drawing with the correct State Plane zone set. Be aware that you have to manually set the zone for the DEM file even though the import dialog will read it.

Allen Jessup