Describe your issue

Beside the bug report here:#1245
and discussions at here: #1290 for extracting one of the isolines,

I'm wondering if it possible to evaluate the isoline at any given location on the mesh? This will apply to circumstances like "extract the isoline at mouse click" for instance.

One workaround I can think of is to generate a large number of isolines and find the one that closest to the target point, but this seems very inefficient.