Electrical wires

[vasja]

Hi, how can electrical wires (any wire) be efficiently (automatic) deleted from a point cloud?

Regards

Vasja

[Terje Mathisen]

vasja wrote:
> Hi, how can electrical wires (any wire) be efficiently (automatic)

> deleted from a point cloud?

Heh! The normal problem is the opposite, i.e. how to detect such wires
automatically.

Anyway, you should probably start with the normal ground point/TIN
generation, then you look for lines of non-ground points following
catenary curves with min/max heights in a suitable range above local ground.

Finding them this way can actually be quite challenging, normally the
number of such returns is so low that they really don't matter for
feature classification if you only care about removing them

Terje
>
> Regards
>
> Vasja
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--
- <Terje.M...@tmsw.no>
"almost all programming can be viewed as an exercise in caching"

[Vasja Bric]

Thanks for suggestions. Yes, usually the problem is opposite; I just need to do an smooth DSM and the wires need to be deleted, especially if the img format is required.

Vasja

[Thomas Knudsen]

For the Danish elevation model, we use a voxel based filtering scheme to remove power lines and bird flocks.

The (unsupported) code is available under a very permissive licence (OpenBSD/ISC) over at https://bitbucket.org/GSTudvikler/gstdhmqc

I think LAStools implements a similar algorithm in at least one of the modules, but I do not remember which.

/Thomas