Mask maps represent a geographical region, discretised by
squared cells with a certain size. With centred around (0,0)
I meant that the geographical location with coordinates
x=0 and y=0 is the centre of the mask map. The cell size
and the number of cells from the centre to the border of
the map should correspond to the number of lags (intervals)
and interval width of a `usual' variogram, respectively.
The point is that you map averages of .5*(z(x)-z(x+h))^2,
averaged over x. The coordinate to write this estimate is
then h, and it makes sense to measure h starting at (0,0).
Hope this helps. If you want a deeper understanding of
variogram maps, try Isaaks&Srivastava, or probably GSLIB
or Pierre Goovaerts' book.
Best regards,
--
Edzer
Shakil_Romshoo wrote:
>
> Dear Edzer J. Pebesma,
>
> Thanks for your response. I did not do that. In fact, I don't understand
> "centred around (0,0)". Would you please tell me how to do that?
> Thanks in advance.
