How to generate isolines (contour lines) at specific values from irregular data?

Question

I have an array of sample points with their (X, Y, Z) coordinates. I use Delaunay Triangulation to generate an irregular network from them and then I use linear interpolation to plot contour lines at fixed values (e.g. 90, 95, 100, 105). The problem is that I need smooth contour lines to be generated with another algorithm. I've searched for some time now and found out that I need to use something like Kriging but I'm not that good at math to implement the algorithm from pure mathematical relations. Also I can't seem to find an implementation or explanation of the algorithm anywhere. Can anyone help me find one? Also, am I right with the chosen algorithm? Is there another one that can be easier to implement? Note that I don't care about precision.

https://dl.dropbox.com/u/15926260/ex.png

P.S. I've done a plot in Surfer showing the results that I'm looking for. On the right side is what I have done using triangulation and linear interpolation and on the left side is what I need to plot using a different algorithm (Kriging was used in Surfer). Sorry for the spelling mistakes but I'm not a native language speaker.

Thank you!

Answer 1

You can try a regular (weighted) delaunay triangulation. In weighted delaunay triangulation triangle areas are more equal. IMO the kriging algorithm seems also to produce more equally contours. Weighted delaunay triangulation is also used to make smoother meshes.