diff --git a/ops_get_dim.f90 b/ops_get_dim.f90
index f08b227..77864fa 100644
--- a/ops_get_dim.f90
+++ b/ops_get_dim.f90
@@ -187,9 +187,9 @@ SUBROUTINE ops_get_dim(spgrid, igrens, xc, yc, grid, nrcol, nrrow, nrrcp, xorg,
 !
 ! Initialise maximum and minimum of x and y coordinates of receptor points
 !
-  xmax = tiny(xmax)
+  xmax = -huge(xmax)
   xmin = huge(xmin)
-  ymax = tiny(ymax)
+  ymax = -huge(ymax)
   ymin = huge(xmin)
 !
 ! --- Skip header if present ---