Create grid cells in a closed curve and check the cells for containment of points

Hello everybody!

I need help with a definition that I am working on.

I have this island(pink curve) and this collection of blue points.

I want to find in which areas are these points more dense.

I have tried to make a grid inside the closed pink curve and then check with containment the number of the points in the cells.

But I am not able to make a grid in the closed pink curve with cells.

Can please anybody help?

Thank you in advance!

Attachments:

point containment.jpg, 203 KB

Replies to This Discussion

Permalink Reply by David Stasiuk on December 4, 2012 at 9:34am

why not make the grid of cells within a bounding box around your curve at the density you like and eliminate all cells whose center point fails the region containment test?

Permalink Reply by Lefteris Siamopoulos on December 4, 2012 at 9:40am

I have tried to do so. But I cannot do a grid into a bounding box. I don't know why!?

I have also tried to trim a bigger grid from the curve but then the cells are lost.

Permalink Reply by Lefteris Siamopoulos on December 4, 2012 at 10:07am

In fact all I want to do is create a grid in the pink curve resulting cells?

Can anybody help me?

Permalink Reply by Marios Tsiliakos on December 4, 2012 at 10:16am

Hi,

I suppose you understand that you can't create a rational grid inside this curve. So, my advice would be to either create a grid of cells from the bounding box(you can achieve this by iso-triming the lower face of the bounding box) like David suggested, or create a convex hull tessellation like voronoi or delaunay to check for containment.

Best,

Permalink Reply by Lefteris Siamopoulos on December 4, 2012 at 10:24am

Of course I know that it cannot be rational but this is not my problem

The thing that I tried both things that you suggested, but in the first case I cannot create a grid in the bounding box, and in the voronoi case I cannot cut of the cells outside the curve.

Could you please make a sample definition?

Permalink Reply by Marios Tsiliakos on December 4, 2012 at 10:32am

Sure, As soon as inget in front of a pc with rhino installed, so you' ll have to be patient if someone else hasn't helped u out till that time.
M.

Permalink Reply by Lefteris Siamopoulos on December 4, 2012 at 10:33am

Ok thanks!

Permalink Reply by Yoann Mescam (Systemiq) on December 4, 2012 at 10:40am