Nature had a nice article on a new tool that uses a diffusion algorithm to produce cartograms, maps rescaled in proportion to spatial variables. I know a bit about diffusion algorithms for image processing, and I can’t resist cool, free GIS software, so I downloaded a copy of the tool, ScapeToad, and tried it myself. First I grabbed a shapefile for US states from the Census’ TIGER/Line product. I clipped that to just the lower 48 states, using MapWindow. Also in MapWindow, I added a column to the shapefile’s attribute table to contain state emissions. In Excel, I used a lookup to insert state emissions from the Vulcan project into my emissions column in the attribute dbf. After a minute or two of chugging in ScapeToad (much more if you want higher resolution), I had this cartogram of state CO2 emissions:
I’ve found trends on Google news interesting for some time. For example, did net news predict a housing bubble?
As online sources of such social data get richer, and control and normalization issues are solved or at least made transparent, they could become a useful input to behavioral models. Already, I find them to be a useful reality check, for seeing how long it takes for events to show up on popular radar, and whether things that seem big are really big in the public mind.
A cool portal for worldwide geological map information has just been launched. OneGeology is a portal, into which regional geologic survey agencies can link their data through a map interface. Users can access map info through a web interface akin to Google Maps. Regional and global layers can be added easily, as in a GIS tool. Here’s a map of rock age for Afghanistan, overlayed on NASA Modis imagery, generated in just a minute or two:
I recently discovered a cool set of tools from MIT’s Simile project. My favorites are Timeline and Exhibit, which provide a fairly easy way to create web sites where visitors can interact with data. As a test, I built an Exhibit containing Richard Tol’s survey of assessments of the social cost of carbon (SCC):