[GRASS-dev] Areas

[Maciek Sieczka]

On Mon, 29 May 2006 13:40:55 +0300 (EEST)
Wolf Bergenheim <wolf+grass at bergenheim.net> wrote:

> Hi!
> 
> When starting to think about areas I played with v.digit a bit, and
> it seems that it creates different cat for the boundary and centroid.

Only if you request it. You can digitize a boundary (any other feature
too) without category. Or with any cat you specify manually, eg. if you
want to attach the new feature to an existant datatable entry.

> Is this what we want? I've always thought of them as kind of bound
> together, and thus would expect them to have the same cat.

> Am Itotally off base here? What about islands? Should they have a cat
> at all, or should they have the same cat as the area that they belong
> to? Or something totally different?

When digitising adjacent areas (sharing a common border line),
categories for boundaries are redundant, if not a disturbance. We
only need cats for centroids then. This also solves the problem of
islands. When the island boundary doesn't have a cat attached,
attributes belong only to centroids in the surroning areas - and no
problem.

That's at least the way I see it.

Maciek

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