In the last tutorial, I showed how to scrape data off a website. This time I’m going to show how to make a basic heat map in Fusion Tables using GIS data. (Heat maps are very en vogue right now.)
Before I start, I do want to point readers in the direction of NYTimes graphics editor Matthew Ericson’s fantastic blog post that came out a while ago called “When maps shouldn’t be maps.” Using several examples, Ericson illustrates a great point: just because data can be mapped, doesn’t mean it should be mapped. (On that note, I will fully concede that trends in the data I use in this tutorial would probably be best visualized in a bar chart, not a heatmap, but it’s data I had on hand!)
Okay, making a map in Fusion Tables requires three things:
1. A shapefile (which is actually a folder with at least four file types in it: .shp, .dbf, .prj, and .shx). You can download your own copy called wards_may2010.zip under “Attachments” from the city’s water billing dataset on BuzzData.
2. A tabular data file whose quantitative data is binned into geographic regions — specifically, regions that correspond to those marked in your shapefile. You can use the cleaned-up copy I made of Toronto’s water consumption data from my clone here.
3. A column of data whose cell inputs — including the header — are exactly identical in both the above shapefile and the tabular data file. (This is the column Fusion Tables matches up to make the merged data table on which your map will be based.)
Got your data? Got your motivation? Then follow the step through this video tutorial and you’ll have your first Fusion tables heatmap ready to go.
If you still have questions, feel free to ping me and I’ll help you out.
Have you tried BuzzData yet? What are you waiting for?