Need DEM help.

[Anonymous]

I'm trying to create a surface using a Lidar data that I downloaded from the NOAA Data Access Viewer. The file  I am able to bring the image into my model space using data connect and the image comes in at the correct location and size. However, when I try to add the DEM to a surface definition as a DEM file it comes in at a wrong location and size. The DEM files projection & datum is projection State Plane 1983, Florida North zone, Horizontal Datum NAD83, Vertical Datum NAVD88, Horiz Units US Feet, Vertical Units Feet, Output project is Raster, Output format is Grid-GeoTiff 32-bit, Grid Units Feet, Grid Size 3. Could someone help me with please? Thank You. 

[AllenJessup]

What type of file did you download? LAZ?

[jroot]

Are you using Recap to create the file?

https://www.asti.com/point-cloud-to-recap-to-civil-3d-workflow/

[Pointdump]

Hi Walt,
Welcome to the Autodesk Forums.
Can you give us a link to where you got the DEM?

Dave

[AllenJessup]

Dave, I Googled the name and got this: https://www.coast.noaa.gov/dataviewer/index.html?action=advsearch&qType=in&qFld=ID&qVal=551#/

I downloaded an LAZ file and brought it into Recap with no problems.

Looks like the OP is downloading the GeoTiff. Most likely a different coordinate system

[Pointdump]

Hi Allen,
Walt said he was able to bring the DEM in with Data Connect, so I'm thinking it's a GeoTiff. I also suspect his DEM is in Lats and Longs, which would account for his inability to add it to his Surface.

Dave

[AllenJessup]

Morning Dave,

I've got too many things going right now to go further with this. Is there a way around that? QGIS or other?

[Pointdump]

Allen,
You can transform a (Geographic Coordinate System)DEM in QGIS to a Projected Coordinate System and then C3D will accept it.

Dave

[Anonymous]

I've tried LAZ and tif files with same results. I did try starting wit a new drawing with CS set to No Datum, No Projection, then used data connection for the tif image. When the image came in it assigned a CS to my drawing. I then created a new surface and added the tif file as a DEM and the resulting surface fell right on top of the image. The surface elevations appear to be correct but the size of the image and surface are roughly 3 times smaller than they should be and they are not located in the correct location.

[Anonymous]

No, I'm not manipulating the LAZ or tif files at all. Not using Recap.

[Anonymous]

Yes. https://maps.coast.noaa.gov/dataviewer/#/lidar/search/

[Pointdump]

Walt,
Can you narrow down your area a little? Can you post your data?
Dave

[Anonymous]

Hi Dave. The files I'm working with are too large to attached but this link should bring up the viewer and list 5 sets of data. I've tried all these with same results.https://maps.coast.noaa.gov/dataviewer/#/lidar/search/-9692248.627760222,3585388.6899443516,-9691799... 

P.S. I'm downloading Qgis and will give it a try. Also, I created surface from a tif file from this same website a few months ago and did not have to manipulate the file. I'm running Civil 3D 2021.

[AllenJessup]

The fact that it comes in 3 times smaller makes me think the data is in metric and you're working in feet. This is what I find in the MetaData.

[AllenJessup]

Also:

[Anonymous]

I saw that and have tried to change the CS of my drawing to Meters, and have tried editing the CS of the image before adding to map but still no go. I think you're right, it seems to an issue between meters & feet. maybe Qgis will work but it looks like it won't complete installing for a few hours. Thanks for your help.

[Anonymous]

It's also strange that although the metadata says vertical datum in meters the elevations of the created surface agree with the elevations on my topographic survey (in feet).

[Anonymous]

I believe I have found a solution. After selecting the image file in data connections I checked its CS and its units are Meters. I changed it to same projection but in feet and added to map. It comes in in the correct location and size and the elevations are correct.

Thank you all for your help!

[Pointdump]

Walt,
I downloaded everything. Each file has a different coordinate system, but they are all projected, so you won't need QGIS. You can do everything in Civil 3D. None of the files are LAS, so you won't need ReCap either.
Dave

[Anonymous]

That's great Dave. I thought I found a solution but it worked only with the image (data connect then edit the files coordinate system before adding to map). But there is no such option when I add the file to my surface. So I'm ending up with the image in the correct location and size but the surface is not correct location or size.