2010 Chattanooga Shootings

I have been working with some people for a while on mapping the sites of the shootings happening in town. There is still a lot of work to do on the data driving the map, but with this being a big part of the conversation going on in the city, I wanted to go ahead and post the map in progress. In this static form it tells us three things. Shooting locations/approximate locations marked by dots, orange dots represent shootings resulting in injury, red resulting in death. The size of the dots corresponds to the number of incidents at that location. (This view focuses on the heart of the city and, therefore, does not include the Sanders Rd. incident.) Once the data is fine tuned and triple checked, there will be an interactive version of this map. As this is a work in progress, please let me know if you see any obvious errors on the map.

Reminder: This map represents three facts and does not represent any crime analysis or interpretation. Oh, and you should click it open to another tab to see if you haven't already.

Pointless and Bible Black

The other day I was looking at a map of Chattanooga that was color scaled to show the percentage of the population that met, or fell short of, some criteria or other. The polygons were, I believe, Census tracts. The color scale went as follows: yellow, green, dark green, blue, black. This is from lowest to highest percentage. The frustrating thing was, of course, that the details for the tracts in black were pretty much illegible. Decisions on cartographic color schemes can be tricky, luckily, there's an app for that....Color Brewer. I think the most important thing I learned from the site was making the color choice based on the function of the colors on the map, whether they represent sequential, diverging, or qualitative data. This might seem obvious, but many maps produced by professional GIS folks fall short. Color Brewer has become an indispensable tool in the Chattadata toolbox. Whether it is making ArcGIS default colors pretty or choosing a palette to use with R, Color Brewer delivers. (For some reason, I find myself using the first version of it more. You should look at both.) I used it tonight on a map, that will show up here once it is all growed up, and it made all the difference.