[R] Does the "labpt" object in the Polygons-class represent the centroid of the polygon

[Roger Bivand]

 <Rizzo.Michael <at> epamail.epa.gov> writes:

> 
> I need to calculate the centroids of some spatial polygons that I have
> placed into a Polygons-class object.  Is the labeling point in the
> Polygons-class the centroid of the polygon?
> 

Yes. The class documentation at ?"Polygons-class" does not state that this is 
the case, because other points might be validly inserted as label points. The 
default constructor uses the centroid of the largest non-hole ring in the 
Polygons object.

Roger Bivand


> Thank you for your help.
>