[vtkusers] vtkCellLocator bug !! new year edition, seems that it is an old bug

[John Biddiscombe]

>from -FLT_MAX (in c++) to +FLT_MAX for (x,y)

Don't do that. It's using all the precision of the float type and leaving
you nothing spare to play with. Use a ray from Maxheight+10% to
MinHeight-10% (max and min of your mesh) then you may not get spurious
results.

I haven't looked at your code, but try the above and see if it helps

JB