Re: Venn diagrams?
- To: mathgroup at smc.vnet.net
- Subject: [mg118269] Re: Venn diagrams?
- From: Murray Eisenberg <murray at math.umass.edu>
- Date: Tue, 19 Apr 2011 06:57:23 -0400 (EDT)
The "mathy" way to say it is simply that the areas should be proportional to the number of objects! I might add that how to draw Venn diagrams is a delicate issue of graphics design: how to shade or color the individual circles and how to shade or color their various intersections. Fairly straightforward a decision with just two sets (and their intersection) being represented, but getting more difficult with three and even thornier with four. As I recall, it's not yet a closed question how to construct a Venn diagram for larger numbers of sets (where, as always, you want them "in general position"). Of course with known sizes of the sets, it's a different matter. On 4/18/2011 6:50 AM, dantimatter wrote: > What I meant by 'to scale' is probably best explained with an example: > > Imagine that group A contains 40 objects, group B contains 30 objects, and > the intersection of A and B contains 27 object. In this case I would really like for the circle representing B to be 75% of the size of the circle representing A, and 90% of B to be overlapped by A. > > (There is probably a more 'mathy' way to say this, but I'm not sure what that is. Sorry about that.) > > Thanks! > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305