> Xin, thanks for your response, but:
> 
> I define two polygons in a dig_ascii file.  The outer one has
> area A, the inner one has area B.  In the dig_cats file they 
> have 2 different categories.  In the dig_att file they have two
> different label points, with the inner polygon's point obviously
> being inside both the inner and outer polygon. 
> When I run d.what.vect and click on the 2 polygons, each one is
> defined correctly, except:  The area of the large polygon is A,
> not A minus B like a donut.  How does the v.in.ascii format
> represent a donut so that the area of the small inner polygon
> will be B, and the area of the large outer polygon will be A
> minus B?
> 
> Cheers, Peter Briggs   
> 
First, I recall earlier mail saying that d.what.vect does not take
into account the possibility of islands (your B). This is clearly a
bug. Second, v.in.ascii does not represent shapes at all, so there
is no data about the area of any polygon until you ask for it to be
calculated (by d.what.vect, for instance). Third, if you really 
need the area data and can stand a little imprecision, you might
v.to.rast the donut and do the area calculation with r.volume. Or
you do the subtraction of (area A+B) - (area B) by hand.


\_\_\_--\_----\_------\_-------------------- P. Martijn van Leusen --------- 
 \_   \_ \_\_\_\_      \_        Dept of Pre- and Protohistoric Archaeology
  \_\_\_  \_ \_ \_      \_        University of Amsterdam, The Netherlands
   \_      \_    \_ \_\_ \_               martijn@scanner.frw.uva.nl
    \_------\_----\_--\_--\_\_\_\_--------------------------------------

