Census geography: Bridging data from prior years to the 2010 tract boundaries>>

MapUSA: Mapping the LTDB data for 1970-2010

This page links to a web-based mapping system that uses the harmonized data from the LTDB standard data files for 1970-2010. Because the tract boundaries for every year are the same (standardized to 2010), this system makes it easier to follow the same tract over time or to see how it compares to its neighbors in different years.

When you open the system, you will see a map of the continental U.S.

• Zoom in or out with your mouse or the +/- tool. Type a street address or place name, even a landmark, in the box to go directly to that location.
• By default you will be shown a street map. You can change it to satellite imagery or a light gray canvas by clicking on “Select a Base Map.”
• To visualize population data from the census, click on the symbol in the upper left corner. This opens a box in which you can choose a category of variables and then a specific variable. You can also drag the slider to choose a different year (the default is 1970). (You can then close this box or reopen it to see the legend.)
• The selected variable will be displayed. If you are zoomed out to show a very large area, the data will be for counties. If you zoom in, census tracts will be shown. Click on a county or census tract to see its exact value on the variable that is displayed.
• A tool is available along the top border to print the map as displayed. Other tools allow you to select an area using your mouse (click on points to identify the outline of the area, double click at the end to close the polygon). “Download” provides the data for the selected area in a new window.
• Click here to see the complete variable list. This list will show you what variables are available in each year. For more detail on the definitions and sources of variables, click here for the complete codebook.
• NEW: the LTDB now includes combinations of racial/ethnic categories that were used by John Logan and Charles Zhang in their studies of global neighborhoods: these are called "Diversity type - general" and "Diversity type - detailed." Click here for explanation.

Click here to enter the LTDB Maps.