Cart: Computer software for making cartograms


This page contains computer software and documentation for creating density-equalizing maps or "cartograms" using the technique described in the paper Diffusion-based method for producing density equalizing maps, Michael T. Gastner and M. E. J. Newman, Proc. Natl. Acad. Sci. USA 101, 7499-7504 (2004).

Downloads

To download the software, click here.

Documentation

For documentation on how to use the software, click here.

Example applications

To see some examples of cartograms created using this software take a look at my cartograms web page or the recent book The Atlas of the Real World, a collaborative project of myself and co-authors Daniel Dorling and Anna Barford.

Questions or comments

I welcome questions about the code, suggestions for improvement, or any other comments. My contact details are here.

Other cartogram software

My collaborator Michael Gastner has also written a program to calculate cartograms using our diffusion-based method. You can find his code here. There are several technical differences between Dr. Gastner's code and mine, including the implementation of the Fourier transforms, the integrator used to solve the flow equations, and the method used to evaluate the velocity field. In practice, this means that the code given here runs somewhat faster than Dr. Gastner's code (typically about a factor of six or seven faster). The two programs are entirely independent, sharing no code whatsoever, which allows you to make an independent check of the results, should you wish to do so. (I know of no case in which the programs disagree.)

A user-friendly JAVA program implementing our cartogram method called ScapeToad has been developed by programmers at the Choros Laboratory in Lausanne. You can find it here. There is also an (unrelated) on-line JAVA version of our method created by Frank Hardisty, which you can find here, and there are free cartogram add-ons for ArcGIS and MapInfo.

Acknowledgements

The original algorithm upon which this software is based was developed in collaboration with Michael Gastner. I received useful feedback from Tom Gross and Danny Dorling during the development of the software. I'd also like to acknowledge the Santa Fe Institute for hospitality while some of the development work was completed.


Last modified: November 6, 2008

Mark Newman