Topo Contour Generation From SRTM data / Contour Line Discontinuity

Hey, guys i’m trying to generate topo contours from SRTM data using grasshopper’s add on ELK. I use it to generate a simple surface of the topo then when i try to generate contours. I see that some (most) of them are not continuous. I mean when i contour a surface it simply cuts it in the xy plane at certain z heights. So a continuous surface will always end up with continuous contours. But in my case it simply does not ? Can someone please shed some light on this issue. I tried to generate contours from both grasshopper and rhinoceros toolbar but non of them gave proper contours.


This is a typical problem with contouring Rhino surfaces, it happens in just basic Rhino as well. The best thing to do is make a mesh and not a surface with the topo data; failing that you could convert the surface to a mesh and contour that. Contouring a mesh is very reliable and will produce polylines; if you need, you can simplify and rebuild them to produce smooth curves.

HTH, --Mitch

1 Like

Hey, Mitch thanks a lot.

It worked. I changed the surface to mesh that boom. It works fine. I will rebuild the poly-lines to make them smooth.