First-order political boundaries in approximately January 1925. Accompanying dbf file shows status of each political unit. Disputed areas generally have their own polygons. Author of file is Sam Brown. Name of the shapefile is WorldBorders1925.shp

This dot map shows three kinds of urban transitions. First, there are indeed areas where changes take place at very precise boundaries — such as between Lawndale and the Little Village, or Austin and Oak Park — and Chicago has more of these stark borders than most cities in the world. But transitions also take place through gradients and gaps as well, especially in the northwest and southeast. Using graphic conventions which allow these other possibilities to appear takes much more data, and requires more nuance in the way we talk about urban geography, but a cartography without boundaries can also make simplistic policy or urban design more difficult — in a good way.

This map service, utilizing data from the Federal Motor Carrier Safety Administration (FMCSA), displays Hazardous Material Routes in the United States. The data in this map is specifically for all roads, highways and interstates, defined as Hazardous Material Routes. At state and national levels, the user can see the national network of these routes and the differences in coverage and expanse by state. At the county and city level, the road symbol changes to include a black border so roads may be better defined against basemap roads. Selecting a feature will bring up a pop-up window indicating the name of the road and highlight all sections of that road, highway, or interstate that are defined as a hazardous material route. Data for this map was obtained through the National Transportation Atlas Database (NTAD) 2012 and is maintained by the Department of Transportation.-----------------The Civic Analytics Network collaborates on shared projects that advance the use of data visualization and predictive analytics in solving important urban problems related to economic opportunity, poverty reduction, and addressing the root causes of social problems of equity and opportunity. For more information see About the Civil Analytics Network.