[GRASS-user] add a centroid in the center of polygon

Markus Metz markus.metz.giswork at gmail.com
Thu Jan 30 14:13:18 PST 2014


On Thu, Jan 30, 2014 at 10:39 AM, Moritz Lennert
<mlennert at club.worldonline.be> wrote:
> On 28/01/14 11:52, Markus Metz wrote:
>>
>> On Mon, Jan 27, 2014 at 9:38 AM, Moritz Lennert
>>>
>>>
>>> Personally, I support MarkusN's idea of merging the two, if that's
>>> possible
>>> from the code point of view. I find it more intuitive to look for a
>>> module
>>> creating centroids...
>>
>>
>> IMHO it will be confusing if there is a flag to calculate the center
>> of mass, but centroids are then not always the actual center of mass,
>> in which case it is safer to assume that centroids are not the center
>> of mass.
>
>
> Well, that's when you come from the GRASS perspective with a very specific
> meaning for 'centroids'. I think for most users centroids are the center of
> mass. So, I'm not sure that this will really be an issue of great confusion.

Centroids, in the sense of v.centroids for which you request the
modification, are calculated in the very specific GRASS meaning of
'centroids', i.e. they really must be inside the area for which they
are calculated. Moreover, the center or mass for two or more different
areas can be exactly the same.
>
> But I won't make an issue out of this. v.centerpoints is already a nice
> solution and I think it should be moved to trunk, although I've stumbled on
> some issues, but I'll file bug reports on those.

Please let me know, I will try to fix these issues.

Markus M


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