Continuing with the cartography series we are going to cover the use of thematic mapping on the GeoWeb. There has been a pleasant up tick in thematic maps being used across the GeoWeb and more attention placed on the cartography of them. Real Estate sites have been using choropleth maps (usually labeled heat maps) for the past few years, but we are now beginning to see them crop up in a wide variety of GeoWeb applications.

Guilhem posted up a nice tutorial on how to create a thematic map with the new Google Maps Flash API on his “Leveraging Visionary Paradigms” blog. Bjørn Sandvik has been putting out a flurry of blog content and applications for thematic mapping. Bjorn’s “Thematic Mapping Engine” is a very cool piece of software and another visually appealing 3D thematic generator similar to UUorld’s time space maps.

I was talking to some cartographer friends about the recent proliferation of 3D thematic maps and they had some concerns about their utility and accuracy. Specifically they pointed to testing that has shown people stink at estimating heights of the countries and have the hardest time telling the most basic differences in height.

Same with estimating sizes of oblique-viewed 3D domes for proportional symbols. The problem is further magnified when the data is re-projected to an Earth globe view making the task of estimating heights/sizes of the polygons even harder (since the user has to mentally compensate for the curvature of the earth). In short their concern is we are sacrificing accuracy for eye candy.

I love eye candy just as much as the next person, which begs the question can we leverage a Z dimension in a more effective manner. One example I like is this 3D thematic in Google Earth:

3d Thematic

The map shows the results of a project where participants are wired up with a device that “records the wearer’s Galvanic Skin Response (GSR), which is a simple indicator of the emotional arousal in conjunction with their geographical location.” While the 3D lines still have the projection issues, I believe it effectively uses 3D to show the data far more effectively than the 2D version (lines varying in thickness).

Criticality aside I think it is great people are pushing the bounds of cartography and thematics on the GeoWeb. Although the cartographers have a great point that we should be aware of the limitations and inaccuracies inherent in some of these techniques.

(editorial note – I blatantly stole the “Is 3D Crap” title from Steve Coast’s “Is 3D Shit” session at WhereCamp.)


6 Responses to NeoCartography and Thematic Mapping: Is 3-D Crap?

  1. Hi Sean,

    Some interesting perspectives you present here. I enjoy reading your blog posts.

    First of all, isn’t it better to use the term “heat map” on maps of this type (a sort of density map), rather than mixing it with choropleth or shaded polygon maps?

    I’ve also got several of the critical arguments about 3d cartography. Some of them are reasonable, others I don’t agree with. I will clearify my arguments on my blog soon – I think it’s best to do it by example. For me it’s not a question of one or the other, rather than giving the user both options. And I think 3d prism maps has some advantages over 2d choropleth maps.

    Eye candy is important, – to give the user something nice to look at has always been important for cartographers, – but it’s of course a problem that “fancy maps” might distract the map reader. But, what’s eye candy today will be plain usual tomorrow…

    I think it’s important to know basic cartographic rules, but it shouldn’t stop people from being creative, – powerful new visualisation tools also need new cartographic rules (or best practices) and skills.

  2. Sean Gorman says:

    Hi Bjorn,

    Thanks for reading the blog. I definitely agree with the heat map comment – choropleths are not heat maps and lots of people label them incorrectly. Actually the picture you refer to was made with our API although we took it off line while we rebuilt our platform. Should be back this fall.

    On the 3D thematic side I’m playing a bit of an intermediary from conversations with folks smarter than myself on cartography. My take is there are pros and cons to using 3D and 2D thematic techniques. I think educating folks on what those are is a great service, and a good debate on it is healthy and useful for the community. I just hope I can contribute effectively because I definitely would not label myself a cartographic expert.

    Look forward to the blog post and learning more. I’ve been trying to track down the reference to the study on 3D thematics my friends referred to and will add that to the discussion if I am successful.

    Lastly you are spot on with pushing the limits and being creative – everyone I talked to was in full agreement on that.


  3. Bjorn says:

    I agree that a good debate is healty. I think we’ll find the best solutions when GIS’ers, cartographers and web geeks are working togheter.

  4. Sean Gorman says:

    Definitely agree and that is one of the big goals with geocommons is to provide one more tool to help that goal.



  5. Sean Gorman says:

    Definitely agree – that is one of the big goals we have with GeoCommons (trying to help and connect those three communities). I hope the incendiary title of the blog post did not obfuscate the message that the folks here are really impressed with the work your pushing out. Ironically at WhereCamp Steve had to admit at the end that 3D was not shit, but the room was packed and everyone was talking about 3D ;-)

  6. Bjorn says:


    There are now 4(!) blog posts about this issue on

    I agree to some extent that accuracy is sacrificed for eye candy, but I’m not yet sure to what extent – and if the drawbacks of 3D visualisation are outnumbering the benefits. I find proportional symbol maps more troublesome than prism maps.

    Sean, I would like to have a reference to the study you write about.