Delaunay 2D connecting wrong points

I’m trying to coloring of a flat surface from a data in a four columns (x, y, z, scalar) .csv format (Dropbox - sqrtJ2SRM-Determ.csv - Simplify your life). I open the .csv file and use the filters “Table To Points” and “Delaunay 2D”, and this is what I get:

But the geometry I get is wrong, the is some lines connecting in wrong places near the slope toe.

See the point data:

How to fix this?


Increasing the value of Alpha in the Delaunay2D filter will improve it.

If the incorrect parts still remain, you may need to select them manually, then check Invert Selection in the Find Data tool to make sure only the correct parts are selected, and use the Extract Selection filter.