Blogs‎ > ‎

Intersection Mapping with GIS

posted Feb 23, 2012, 8:46 AM by Crash Congestion
For my deliverable, I have been working on creating an interactive map of the intersections in Santa Fe. I have been experimenting with a few different applications for doing this including GIS Cloud, Google Mapper 2.0, and Google Fusion Tables. GIS cloud is the more powerful of the three but it has a more complicated user interface and is difficult to customize. My goal was to use GIS to place a "pin" on every intersection and then create info boxes that would pop up with more information about the intersection when a specific pin was clicked.

I decided to use Fusion Tables because it allows you to automatically create info balloons from data in a spreadsheet. Unlike Google Mapper which supplies some templates but for more customization requires HTML coding skills. 

Since our team does not have any data in excel format yet, I used the signaled intersection data from last years SF lights team. To create a map with Fusion Tables, all you need to do is copy the desired data into a Fusion Tables spreadsheet and then designate each column. Columns for latitude and longitude must be designated as well as a name. The user has the option to designate as many secondary columns as needed. I created columns for volume and crash measurements including the EPDO (Equivalent Property Damage Only) and the AADT (Average Annual Daily Traffic). 

As you can see above, there are three different colored pins. These colors differentiate between the three possible EPDO values 1,5 and 10. A value of 1 results in a green pin because it represents an accident with only property damage. A yellow pin represents a five or an accident with injuries. Finally, red pins represent fatal crashes or an EPDO value of 10. The info boxes that pop up when a pin is clicked display more information about that intersection including address, coordinates, and traffic measurements. The interactive version of this map can be viewed here. More intersections will be added to the map once we have our crash data in a usable format.

- Ray Casola