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Remove Contour Lines From Water Surfaces

#1

I generated a DTM and Contour lines with Noise Filtering setting on and Smoothing set to smooth.  5ft contour invervals. It came out pretty good but obviously there can’t be contours on water surfaces.  It’s not that bad though and if the water is shallow I would guess I may be seeing contour lines effected by the contour of the bottom of the ponds which is interesting!  But I’ve heard that this is a common issue even when the water is deep.  I went to try to remove points from the point cloud and found that the water surfaces in the Ray cloud Viewer were all black, and was thinking doesn’ that mean there’s no points there?  I suppose it can’t mean that as then why are their contour lines there?

Also how do you remove those camera projections when viewing the ray cloud?

 

#2

Hello,

The water is indeed a problem when working with photogrammetry as it is not possible to find automatic tie points (or even manual points). There are several reasons for this: the water is radiometrically homogeneous, it is moving…

In case there are matched points in the water, they will probably be incorrect so it is good to remove them.

AS you say, having a “black hole” in the water area means that there are no points there.

I would have to check the project but I would say that the fact that there are still contour lines generated is because the software interpolates points when generating the DTM.  Even if there is no information, some areas can still be filled with surrounded points and I think that is what is happening here.

I hope my answer helps you.

Regards.