# Applet For Drawing Exact 3 Set Area-Proportional Venn Diagrams with Convex Curves

The ideas behind this applet are outlined in a paper submitted to Diagrams 2010.

## Instructions

The applet draws Venn Diagrams with 3 curves. It makes each of
the *regions* proportional to the *population*
(value) assigned to it.

To draw a diagram with your own data, simply type in the data for the zones
in the 'population' column, and click the 'Draw Diagram' button, you should map
the 3 set names of your data to A, B and C. The population values can be any you
like, the program will scale them. The 'Measured Area' column gives a confirmation
that the regions are the correct area (or, if they do not match, a indication that they are wrong).

By default the label in each zone is the population. You
can create an unlabelled diagram by choosing the 'No
Labels' option. The display of the curves and shading
can be altered by the 'Colour', 'Shading' and 'Dashed' options.

The diagram types are explained in a paper submitted to the
Diagrams 2010
conference. In summary, the 'Core-Triangular' and 'Triangular' options will
not draw all specifications. 'DT-Triangular' and 'CH-Triangular' should be
able to draw all specifications, in a convex manner where possible. Note
that due to bugs, some specifications are not drawn correctly. The
'CH-Triangular' type draws some specifications in a convex manner that are
only drawable with non-convex curves with the 'DT-Triangular' type. The
'Layout Improvements' option only works with 'CH-Triangular' diagrams

At the moment the only way to use this diagram is to take a screen shot
('Print Screen' key in Windows) and paste the bitmap into a document.

The Euler Diagrams Visualization
project has developed further tools of this sort.

The use of the results of this applet is free for research and non profit
use.

## Related Work

- If you want to draw these diagrams with three circle Venn diagrams (with approximate
area-proportionality) use the
3 Circle Venn Applet
applet.
- If you want to draw two circle Venn diagrams (with exact
area-proportionality) use the
DrawVenn
applet.
- Constructing these sorts of diagram is a fascinating problem. For more
information on Venn Diagrams (diagrams where all zones appear) see the
Venn Diagram
Survey.

Ideas used to generate this work were developed by

Peter Rodgers, University of Kent, UK; Jean Flower, Autodesk; Gem Stapleton and John Howse, University of Brighton, UK

Contact: Peter Rodgers, University of Kent, UK (email)