The easiest way to create thematic maps by state, county, or zip code

Posted on January 21, 2010 by Doug McCune

We've just launched new thematic mapping features in SpatialKey that let you create maps of your data by state, county, or zip code with a few simple mouse clicks. We think this is the easiest way to create thematic maps - ever. To show off these abilities I'll show an example of creating a thematic map of unemployment rate by US county. The end result will look like this:


Find some data

Your data must have location details down to the level of granularity that you are trying to map. For instance, if you want to show a map of states, all the records in your data should at least have US state (your data can be more granular too, you can map address-level data by state if you want). In this example I'll be mapping US unemployment rate. The data for unemployment is provided by the Bureau of Labor Statistics and can be found here. I took the latest stats by US county and extracted only the data for October 2009.

After just a little massaging in a spreadsheet program my data looked like this:


You can download the CSV file that I used if you'd like to try it out for yourself.

Upload to SpatialKey

Once you have your data ready, you can upload it to SpatialKey. If you don't already have a SpatialKey account, you can sign up for the free 30-day trial to get access right away and start uploading. During the upload process you'll be asked to identify the location columns in your data, like street address, zip code, etc. We'll do our best to automatically identify these columns based on your data, but you might have to help us out.


Make your map

When you load your data onto a map you'll be asked what kind of map you want to create. We'll make a thematic shape map, and we'll choose to map the data by US geography (this includes state, county, or zip code).


Then we choose what the map should display. In this example we want to show the unemployment rate, so I'll pick average unemployment rate, which will start me off with a map of the US states with the average unemployment rate for all the counties in each state.


Now our thematic map shows the average unemployment rate for all the counties aggregated by state.


I can switch between this state view of the data and counties by changing the options in the layer's settings panel.


Now we have a map of all the counties in the US (including Puerto Rico) that shows the unemployment rate of each county.


Customize and Explore

You can easily customize the bin ranges if you want to tweak them, or you can control the colors used (all maps are the same, just with a different color scheme):



You can also use all the filtering options that SpatialKey offers to filter the data in your thematic maps. Here's an example of filtering to only show counties where the total labor force is over 100,000.


And here's another example to show only the counties where the unemployment rate is greater than 15%:


No Programming Required

To generate these maps you don't have to write a single line of code. It's as simple as uploading your data and stepping through a few guided steps. If you wanted to change the map to show the total labor force per county instead of the unemployment rate, it only takes 3 clicks. There are lots of ways to make these maps, like this great tutorial on FlowingData shows, but we think SpatialKey gives you the easiest way to create and analyze thematic maps.

This entry was posted in examples, thematic, choropleth by Doug McCune. Bookmark the permalink.