[!! SPAM] [GRASS-user] digitisation of an adjacent polygon

[Hamish]

ramarajua wrote:
> I am using grass digitisation tools and wants to know wether it is
> required to redigitise the common boundaries between the adjacent
> polygons. Also let me know how to add islands, merge two polygons into a
> single polygon. Thanking in advance
[...]
Maciej Sieczka wrote:
> To create a polygon digitize it's boundaries, make sure their nodes are
> snapped, digitize centroid within each polygon. In GRASS, a polygon is
> made of boundaries and a centroid inside.

and to make an island digitize a boundary but give it no centroid.

to merge two polygons you can use v.dissolve, that only dissolves
boundaries if the areas on either size share the same category value,
or (in GRASS 6.3) you can use the column option to base the dissolve on
some attribute column in the attached database.


Hamish