[GRASS-dev] using slope/aspect functions inside our module

[Dylan Beaudette]

On Wednesday 04 July 2007 08:41, Glynn Clements wrote:
> "Carlos \"Guâno\" Grohmann" wrote:
> > Interesting.
> > Why r.slope.aspect uses
> >
> > dx = ... / (4 * ewres);
> >
> > while r.shaded.relief uses
> >
> > dx = ... / (8 * ewres);
> >
> > ??
>
> Oops. It should be 8; the ewres/nsres values are actually the
> distances between the centres of the top/bottom rows and left/right
> columns in the 3x3 window, which are two rows/columns apart. IOW, the
> 4*ewres should have been 4*(2*ewres) = 8*ewres, ditto for nsres.

Yikes, does this mean that previous calculations are now wrong?

dylan