[GRASS-dev] Re: [GRASS-user] vector layer labelling doesn't work....

[Moritz Lennert]

G. Allegri wrote:
>> I would hesitate to add GV_CENTROID automatically when displaying
>> labels. Attributes are connected to the primitives like points,
>> centroids, lines or boundaries, not areas! In d.vect when you ask to
>> display 'area', you ask for filling areas, nothing else. Labels are
>> not connected to areas but to the centroids. So you basically cannot
>> ask to display area labels. This should be explained in d.vect manual
>> rather then changing the code. Just my opinion.
> 
> Yes, ok Martin. But that would be for "user-friendness". Conceptually,
> with your logic, also d.what.vect should work only if a centroid is
> clicked, not on the whole area...
> Centroids are borned to make areas exist, so they're conceptually
> strongly related, so it doesn't appear an error to me to consider
> labels (attributes) directly related to areas... my two cents. I
> repeat, just for "user-friendness"
> 

I have no definite opinion on this, but I see Giovanni's point and I 
think the latest patch I posted responds to this: labelling areas when 
areas+labelling is asked for, without showing centroids...

So, let's ask for more opinions: should labelling of areas be linked to 
centroids only, and thus display of centroids obligatory for seeing 
labels for areas, or should labels for areas be displayed even if 
centroids aren't ?

I filed this as an enhancement ticket on Trac:
http://trac.osgeo.org/grass/ticket/252, so maybe discussion should go on 
there.


Moritz