Find points with a certain amount of neighbours

[strudismizzle]

Hello!

I am currently searching for a solution for the following problem:

A certain pointcloud (planar) is given. I want to find the contour lines, e.g. when the point cloud looses density and later connect these areas with a polyline (blue in picture).
I therefore need to extract these contour points and then connect them. A way to find the contour points would be to etract all points, which dont have a certain amount of neighbours, but I am not sure about this approach.

elevation gh.3dm (28.4 KB)
elevation_re.gh (126.3 KB)

best
strudelone

[Joseph_Oster]

These threads might be relevant?

Strategy for removing points inside PointCloud

I managed to get a “concave mesh” (white group) and perimeter boundary around the point cloud. I left out the Graph Mapper from the other model that causes the gradient effect and cull all the points within ‘edge_L’ distance from the perimeter. [CullInnerArea_pointcloud_2020May15a] CullInnerArea_pointcloud_2020May15a.gh (228.8 KB)

Delaunay mesh points/edges excluded

Cull faces with long edges. [delaunay_mesh_2021Jan9a] delaunay_mesh_2021Jan9a.gh (70.0 KB) P.S. Instead of culling faces based on perimeter length, you can use length of longest edge: [delaunay_mesh_2021Jan9b] delaunay_mesh_2021Jan9b.gh (73.3 KB)

[HS_Kim]

elevation_reV2.gh (138.0 KB)

[strudismizzle]

Amazing. Thank you so much!