Friday, March 11, 2016

Dorling Cartograms for Better School Days

Today the Huffington Post are promoting's BestSchoolDay campaign, The campaign is asking members of the public to donate to classroom projects across the USA.

The Huffington Post and Stamen Design has created an interactive map which visualizes the total number of projects and the total number of unfunded projects in each state.

The map includes a really clever 'bubbles' view. Select the 'bubbles' button and the map transitions to a Dorling Cartogram of the same data. The shape of each state on the map transitions to a circle which is scaled to represent the number of projects in that state.

If you want to know more about Dorling Cartograms then there is a really great description at ArcGIS. If you want to make your own map that transition into a Dorling Cartogram you could start with d3.js. Mike Bostock has created a nice example in which the state of California transitions into a circle.

In Mike Bostock's Shape Tweening example topojson is used to create a map of California which then transitions into a circle. If you want to change the size of the circle to represent a data ratio then you just need to adjust the radius variable in the JavaScript to represent the size of your data.

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