Sketching Euler Diagrams

This EPSRC funded project [EP/H048480/1] focuses on developing sketch recognition techniques for Euler diagrams.

A natural creation method for Euler diagrams is using a pen but, prior to this project, no intelligent tool support existed for the pen-based creation of diagrams of this type. Euler diagrams are a popular and frequently used visualization technique; in part, this popularity serves to motivate our selection of them for the proposed research, since the results are likely to have significant impact. Moreover, Euler diagrams form the basis of more expressive notations, built by augmenting them with graphs or arrows (or both), for instance. Example notations include spider diagrams, Euler/Venn diagrams, Venn-II diagrams, constraint diagram, and concept diagrams. The research results of the project provide a basis for developing sketch recognition tools for these more expressive notations.

The figure below shows a sketched Euler diagram (on the left) alongside a formal Euler diagram (on the right). The sketch was drawn on a touchscreen and automatically converted to the formal version. The conversion process relies on being able to distinguish text from curves. In addition, sketched curves which are approximately circles or ellipses are rendered as these shapes in the formal diagram.

Previous work on sketch recognition has focused on types of diagrams, such as graphs, where properties like connectedness are semantically important. Euler diagrams, by contrast, use containment and overlap in semantically significant ways. Thus, the process of converting a recognised sketch to an Euler diagram must ensure that these properties are preserved.

The project runs from 2010 - 2011 and the proposal can be found here, which contains full details of the aims and objectives.

Project Team

Dr Gem Stapleton is the Principal Investigator and Aidan Delaney is the Co-Investigator. The project runs in collaboration with Dr Beryl Plimmer at the University of Auckland who is a leading expert in sketch recognition software. In addition, Nokia Research are an official Project Parter and Dr Peter Rodgers is also collaborating on the research.

So far, the project has led to the development of two sketch recognition tools: SketchSet and SpiderSketch. To see SketchSet in action, you can download this video. We acknowledge the significant contribution made to the implementation of SketchSet by Mengdi Wang and Paul Schmieder, both at the University of Auckland. SpiderSketch recognises Euler diagrams augmented with graphs and shading and can be freely downloaded.


The following publications directly contribute to the project outcomes.

  1. A. Delaney, B. Plimmer, G. Stapleton, P. Rodgers. Recognising Sketches of Euler Diagrams Drawn with Ellipses. Visual Languages and Computing, Knowledge Systems Institute, pages 305-310, 2010.
  2. M. Wang, B. Plimmer, P. Schmieder, G. Stapleton, P. Rodgers, A. Delaney. SketchSet: Creating Euler Diagrams using Pen or Mouse. Visual Languages and Human-Centric Computing, IEEE, pages 75-82, 2011
  3. G. Stapleton, A. Delaney, P. Rodgers, B Plimmer. Recognising Sketches of Euler Diagrams Augmented with Graphs, Visual Languages and Computing, Knowledge Systems Instutite, page 279-284, 2011.