20 replies to this topic

[Matthew Hampton]

It was my understanding that Gastner and Newman's basis on diffusion gas laws used a more precise density-equalization algorithm. The trick is maintaining a recognizable shape. I think their process can be taken another step forward by weighting the boundaries, or at least simplifying the geography first, then running it through the density-equalization.

I guess it will be easy to test when the next version of ArcGIS (adding polygon generalization) comes out. It's really great that Hardisty made an applet, but I wish it would support bi-variate data.

[franciscocartographer]

I completely agree with the generalization and some separation of boundaries.
I believe cartograms should be used more often especially now that are easier to construct and more readable with the diffusion technique developed by Gastner – Newman. Moreover they should be accompanied with text explaining what a cartogram is.

I wrote a small research paper at school (2003) comparing cartograms with proportional (Flannery) symbol maps. I developed a questionnaire and gave it to a sample of 14 undergraduate students (I know the sample was too small). The overall conclusions were that cartograms are as effective as proportional symbol maps in representing human phenomena, they represent better quantitative aspects of variables, and are difficult to understand.

Here is a graphic of the qualitative conclusions:

Attached Files

•  AttitudesCartogram_03.gif   21.14K   109 downloads

[frax]

Im not so convinced of the communicative power though. It works best when there are very strong regions vs very weak regions (as in a global GDP map) but the feedback from the water map (in the map gallery) I did in September is that it is cool but very hard to interpret...

[GlossopJohn]

Hi all

Greetings from sunny Sheffield, UK.

I was trawling the web looking for stuff on cartograms, and came across this topic. I work for Danny Dorling, and I'm helping him in a collaboration with Mark Newman to produce lots of world cartograms.

The website we're creating for the project is in its infancy, but I though you might like to take a look, as the first few cartograms are on there. It's at http://www.worldmapper.org/

Most of the maps aren't there yet, and the information is a bit sketchy at the moment... we're working on it. But I'd appreciate some suggestions and/or constructive criticism.

Regards

John Pritchard
Sheffield University

[DaveB]

The website we're creating for the project is in its infancy, but I though you might like to take a look, as the first few cartograms are on there. It's at http://www.worldmapper.org/

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Interesting maps/cartograms. It would be cool to see an animation of the population ones.

I noticed a spelling error or 2 just browsing around (sorry, didn't make note of them). The maps that cycle in the main page go by a little too fast, but then you can always go browse the various map categories.

[franciscocartographer]

Very nice collection of cartograms, John. I like the fact that the graphics are accompanied by text and graphics summarizing the data. I think that the regular educated individual will understand cartograms using explanatory text and graphs. Also, the colors help one identify the areas represented.

I will personally get rid of Antarctica since there is no population there and its area in a cartogram will be equal to 0.