DEM

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Sile
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Joined: Tue Oct 10, 2017 3:40 pm

DEM

Postby Sile » Tue Oct 10, 2017 3:51 pm

I am having trouble creating a Digital Elevation Model (DEM). I need to need to take my ground points and move them all to the same height, while keeping my higher points (vegetation) in their same X,Y coordinates. I have not been able to find how to do this throughout videos and other forums. Any help would be much appreciated.

Cheers

daniel
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Re: DEM

Postby daniel » Tue Oct 10, 2017 6:29 pm

Hum, do you already know what are your ground points? If yes, then if you can make a separate cloud with them (generally with the 'Edit > SF > Filter by value' tool), then you can:
  • add a 'constant' scalar field to this cloud (Edit > SF > Add constant SF) - set the unique value to the target height of your ground points
  • convert this scalar field to the Z coordinate (Edit > SF > Set SF as coordinate(s))
  • merge this cloud with the vegetation cloud
Daniel, CloudCompare admin

Sile
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Joined: Tue Oct 10, 2017 3:40 pm

Re: DEM

Postby Sile » Tue Oct 17, 2017 7:17 pm

I do not have my ground and vegetation points seperated. I am using a xyz file. I do not know how to separate these. Any help would be much appreciated.

daniel
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Re: DEM

Postby daniel » Tue Oct 17, 2017 7:21 pm

Daniel, CloudCompare admin

Sile
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Re: DEM

Postby Sile » Wed Oct 18, 2017 5:32 pm

I figured out how to separate the vegetation and ground points. However, if we could look back at my first question on how to make a DEM. I created the DEM of the ground points, but I am having problems with snapping the vegetation points back. When I fuse/merge the two clouds together, there is no merging action happening. The window that shows which cloud you selected combines the two. Unfortunately, I cannot show you a picture of what it looks like because the file is too big.

daniel
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Re: DEM

Postby daniel » Wed Oct 18, 2017 9:19 pm

Are you trying to merge a mesh with a cloud? (I don't know what was your exact workflow). If yes, then you'll have to convert it back to a cloud.
Daniel, CloudCompare admin

Sile
Posts: 21
Joined: Tue Oct 10, 2017 3:40 pm

Re: DEM

Postby Sile » Thu Oct 19, 2017 1:49 pm

From the best of my knowledge, the "off-ground points and ground points" are both point clouds.Image. Try using this link to see the photo that I posted to facebook.

Sile
Posts: 21
Joined: Tue Oct 10, 2017 3:40 pm

Re: DEM

Postby Sile » Thu Oct 19, 2017 2:03 pm

I attached a photo of what I am trying to do. I don't think we are understanding each other. Thank you for your time and patience.
Attachments
Capture 1.PNG
Capture 1.PNG (118.9 KiB) Viewed 652 times

cdordoni
Posts: 24
Joined: Wed Sep 30, 2015 3:19 am

Re: DEM

Postby cdordoni » Thu Oct 19, 2017 4:09 pm

Daniel,

DEM is a general term that is used for both DTM and DSM data.
https://www.gisresources.com/confused-dem-dtm-dsm/


The true ground surface is obscured by trees or buildings, so when the trees and buildings are removed, there are holes. To create the DTM, the holes are filled in.

To get the actual surface (DSM) including the trees and buildings, that data has to be added back in.

Sile
Posts: 21
Joined: Tue Oct 10, 2017 3:40 pm

Re: DEM

Postby Sile » Thu Oct 19, 2017 5:17 pm

Yes, so is that possible to do in cloudcompare or do I need to run it with another software platform?


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