Do not use `convert_to_ind`

Not worth it for a single point.

Overlap/read_snapshot.f90

@@ -7,7 +7,6 @@ contains
   subroutine read_snapshot(s, hshpc, ssm, k, copy)
 
     ! Libraries:
-    use contour_531, only: convert_to_ind
     use jumble, only: assert
     use numer_rec_95, only: hunt
 
@@ -69,7 +68,7 @@ contains
     if (s%number_extr /= 0) then
        if (s%list(1)%extr%coord_proj(1) == huge(0)) &
             forall (eddy_i = 1:s%number_extr) s%list(eddy_i)%extr%coord_proj &
-            = nint(convert_to_ind(s%list(eddy_i)%extr%coord, corner, step))
+            = nint((s%list(eddy_i)%extr%coord - corner) / step + 1.)
     end if
 
     ! Define s%extr_map from s%list%extr%coord_proj: