[GRASS-user] mapcalc and cell coordinates

[Glynn Clements]

Moritz Lennert wrote:

> > Also note that the calculation involves multiplying by the resolution. 
> 
> You mean internally by mapcalc, or that I should include resolution into 
> the calculation ?

Internally.

The point is that if you have e.g. a 100m x 100m square, and you set
rows = cols = 300, so each cell is 1/3rd of a metre, *all* of the cell
centres will suffer from rounding error, even when the row and column
are multiples of 6, as the calculation will multiply by (a binary
approximation to) 1/3, not divide by 3.

-- 
Glynn Clements <glynn at gclements.plus.com>