I have a regular grid. I need to subtract some irregular part from it as shown in the figure. I know the coordinates of the portion to be subtracted. How can I polygonize the rest of the grid after subtracting that irregular portion? There may be a number of ways. Could any one give me some suggestions?
Polygonizing a grid after subtracting an irregular portion
I have a regular grid. I need to subtract some irregular part from it as shown in the figure. I know the coordinates of the portion to be subtracted. How can I polygonize the rest of the grid after subtracting that irregular portion? There may be a number of ways. Could any one give me some suggestions?
Construct a Delaunay triangulation from the vertices?
Here I only know the grid points And the boundary points to be subtracted. Boundary points may not fall within the grid points. Then with which coordintes I need to construct the delaunay triangulation? Could you explain?
Well, you could triangulate the boundary, do an intersection test of all the grid points against the triangles, remove those which intersect then retriangulate with all remaining points?Here I only know the grid points And the boundary points to be subtracted. Boundary points may not fall within the grid points. Then with which coordintes I need to construct the delaunay triangulation? Could you explain?
Wouldn't be particularly efficient but should work I guess...
If using python, Shapely is a nice library for stuff like this.
When you say polygonize, what do you mean? Triangulate? Otherwise it's just a 4 segment polygon with a hole in it, or a many-segment polygon which will have a shared edge running from the outside to the inside hole.
Yes, I am looking for some triangulation method suitable for my work and which will also be efficient.
I have some question. When boundaries are extracted from images, I need to know how surface or 3D model are usually reconstructed from edges. As i am doing something similar, a similar kind of aproach may helpful to me.
Here I also need to interpolate color values. That's why I preferred about constructing a grid so that color values can be extractd at close intervals. Please suggest me about any better or convenient approach.
Well, for triangulation Triangle (2D) or QHull (2D, 3D) might work for you. I've only worked with Triangle, but found it easy to work with and it supports holes.
If you're trying to create a polygon mesh out of the results, it should be pretty trivial once you have your delaunay triangulation done. As easy as creating a triangle list out of the results.