[GRASS-dev] v.what.rast support for centroids, v.rast.stats speed, r.category update

Wolf Bergenheim wolf+grass at bergenheim.net
Wed Oct 10 04:35:08 EDT 2007

On 10.10.2007 10:11, Hamish wrote:
> Michael Barton wrote:
>> This brings up an issue that we might want to think about for GRASS 7.
>> Currently, centroids must always be created manually to transform a
>> closed polyline into an area. While we might want to keep this as an
>> option (but maybe not), I think it would be better to have some kind of
>> 'area-creation' utility that would transform a close polyline into an
>> area by automatically adding a centroid at a predefined center location
>> (geometric center or other measure) and adding a cat value. Then
>> analytical utilities like you are discussing here could be more
>> reliable.
> (v.type + v.centroids)
> I don't think you can convert automatically all closed boundaries as
> some of the closed boundaries may be islands/holes within an area, and
> you risk turning them into positives.

I agree with Hamish, however, I think it might be worth considering that
we could have 2 new area creation buttons: "create area" and "create
island/hole" That could make it easier for the new user to start with
digitizing in GRASS. An advanced user would maybe choose to use the
"draw boundary" and "draw centroid" buttons, which would sit there next
to the new area drawing buttons. The purpose of the GUI is after all to
make it easier/friendlier to operate GRASS.



<:3 )---- Wolf Bergenheim ----( 8:>

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