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elevation difference between DEM and DTM?

no idea
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no idea
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jeffafah

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elevation difference between DEM and DTM
« on: March 24, 2017, 02:21:04 PM »
Hi all,

I classified a pointcloud into ground and nonground. Afterwards I duplicated the chunk and build the DEM in both chunks. One DEM was the real DEM, means ground and nonground points. The other "DEM" was the actual DTM (surface / terrain) made of only ground points.

Now the problem:
I got some markers far away from trees, buildings etc... At this markers I ve got an elevation difference between those two DEM/DTM of about 10 upto 20 cm. Does anybody have an idea why that happens?

thank you very much
jeffafah
« Last Edit: April 10, 2017, 03:20:23 PM by jeffafah »

ericktreichel

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Re: elevation difference between DEM and DTM
« Reply #1 on: February 17, 2019, 01:08:34 AM »
Hi all,

I classified a pointcloud into ground and nonground. Afterwards I duplicated the chunk and build the DEM in both chunks. One DEM was the real DEM, means ground and nonground points. The other "DEM" was the actual DTM (surface / terrain) made of only ground points.

Now the problem:
I got some markers far away from trees, buildings etc... At this markers I ve got an elevation difference between those two DEM/DTM of about 10 upto 20 cm. Does anybody have an idea why that happens?

thank you very much
jeffafah

I would like to know too.
Thanks if anyone can help!

gto234

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Re: elevation difference between DEM and DTM
« Reply #2 on: February 17, 2019, 09:39:47 AM »
Interpolation maybe?

Alexey Pasumansky

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Re: elevation difference between DEM and DTM
« Reply #3 on: February 17, 2019, 08:09:40 PM »
The estimated location of the marker that is displayed in the Reference pane is based on the marker's projections on the photos, so it doesn't depend on the reconstructed DEM surface.
Best regards,
Alexey Pasumansky,
Agisoft LLC