A cartogram is a map where areas or lengths are distorted to represent thematic content such as population or GDP. This sample is a Silverlight-based web application that maps cartograms of international tourism, immigration and trade in dairy, meat and fruit.
The live application is available here.
The source code can be downloaded from here.
The data used in this application is derived from spreadsheets downloaded from Worldmapper. Cartograms of this data were generated using this geoprocessing tool developed by Tom Gross and published on ArcScripts. For data analysis and presentation we selected the Geood homolosine projection because it is equal-area and looks cool.
In my opinion, the most interesting aspect of this sample is its ability to animate between various cartograms. This is achieved using an inherited Graphics class that can interpolate geometry at a giving instance in time. This will be the subject of a future posting that will discuss this in more detail.
In summary, cartograms are useful technique for showing the distribution of thematic values particular when the data has a wide distribution. However cartograms are not suitable if the map reader is unfamiliar with the original shape of geometries.
Contributed by Richie C.