[GRASS-user] Default method of rasterizing in v.to.rast

[Markus Metz]

On Mon, Feb 23, 2015 at 1:05 PM, RichardCooper <richtcooper at hotmail.com> wrote:
> Hi,
>
> I'm trying to determine the default method of rasterization used by v.to
> rast.
>
> In the v.to.rast manual it states in relation to the  -d option, that 'All
> cells touched by the line will be set, not only those on the render path',
> but I'm not certain which method is being used by default.

The -d option applies only to lines, default is only those on the
render path (thin line).

>
> I came across a paper by  Biagi and Negretti
> <http://geomatica.como.polimi.it/workbooks/n2/articoli/lbmn.pdf>   * which
> describes how by default vectors are rasterized in GRASS  5. The latter
> authors refer to the 'center' method as being the standard GRASS command in
> 5.0 (p. 4). Is this used in GRASS 7? From my observation (in the Map
> Display), by default, vector area appear to be rasterized if the center of
> the grid cell falls within the area boundary?

Yes, or the other way around: a grid cell belongs to the area where
the grid cell's center falls into.

Markus M

>
> I haven't checked through the code, but maybe someone has some knowledge on
> the history of v.to.rast?
>
> Cheers,
> Richard
>
> *http://geomatica.como.polimi.it/workbooks/n2/articoli/lbmn.pdf
>
>
>
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