Here is the interactive map demonstrating the various node locations, as listed in the 'Data View' section.
The same map allows for different formatting and views to ensure maximum readability for whoever is reading the map. Off to the side, are the other alternative views; different time scopes, and air pollutants, for an example. Below that, one can notice the ability to compare two different nodes (i.e. locations) and the various aspects of data of them (pollutants, temperature, etc.)
There are also alternative map views, for an example a more realistic one which depicts more topographical information, as opposed to the road map view, which shows streets, expressways, and towns.
The data view locations correspond to locations on the map, where there are map markers. Each node/location has a line of data; such as user-set parameters currently active, and the measurements of each parameter. Other standard information included is latitude/longitude, time of update, and the city/country. (always Chicago, and the U.S. for our purposes).
One should notice that the nodes are spread roughly the same length apart, to ensure a nice, even distribution of data collection, in an attempt to get a well-rounded collection of the Chicagoland area.