Contours from a 3D point cloud

You can generate contour lines from a point cloud.

You have two options:
– process a digital elevation model and then generate the contour lines from it;
– create contour lines directly from the point cloud.

The first method follows the same principle as GIS software do.

The second is much more similare to a topographical triangulation.

Regardless of what you choose, which depends (a lot) on the software you use, the contour lines must be representative of the terrain.

So, i would recommend:

• to clean the point cloud, removing everything that is not ground (trees, cars, buildings, …).
• Lower the density of the cloud to avoid “nervous” curves (because they rely on many points).
• Simplify the cloud according to the step of the contour lines. If you have to build contours that represent 1 meter of elevation it is not necessary to have a cloud with points 1 cm apart from each other.
• Check the result and be ready to work on it a bit to fix the lines, if necessary.
• Be prepared to have areas where the curves are interpolated because you may have holes in the point cloud.

I’m actually using LiDAR360 and it has a very good contours generation algorithm directly from the point cloud!

Ciao!

Paolo Corradeghini