@DIN transformation

[Bruno Levier <blevier@xxxxxxxxx>]

Hi,

I would like a explanation about the @DIN (definite integral)
transformation.               

If we apply the transformation simultaneously to both the Y (latitude in  
units of degrees) and Z (depht in meters) axis, the command

   yes? list/x=5/l=1 var[y=42:43@din,z=0:500@din]

seems to be equivalent to :

  yes? list/x=5/l=1 var[y=42:43@sum,z=0:500@sum] * Ly * Lz * cos(42)

with Ly and Lz the constant length of the grid-box for latitude and depth
respectively.

I dont understand why it is multiplicated by cos(y).

Thanks to enlighten me.

Bruno LEVIER