A new mapping project from University of Richmond’s Digital Scholarship Lab has provided an interactive and historical look at the way the federal government initially established economic inequality and discrimination.  Mapping Inequality is a database of more than 150 federal “risk maps,” an effort executed by the New Deal Program that would dictate decades of economic discrimination in cities.

They’re a reminder that letting huge swaths of the American city fall apart was essentially federal policy beginning in the Great Depression, when banks began to withhold lending from certain communities based on color-coded risk maps.

As reported in Henry Grabar’s article on Slate.com, the Home Owners’ Loan Corporation, or HOLC, brought together mortgage lenders, developers, and real estate professionals in hundreds of American cities to design four-color maps. Neighborhoods were shaded green (“best”), blue (“still desirable”), yellow (“definitely declining”), or red (“hazardous”), in descending order of credit-worthiness. These maps, which came to shape not just the distribution of mortgages but other types of lending and investment, were the origin of the term “redlining.”

The innovation of the Mapping Inequality project is that it links maps from scores of American cities with contemporaneous neighborhood reports, which allows you to toggle easily between maps and more detailed descriptions. What’s revealed is how the mapmakers’ obsessive focus on racial “infiltration” dominated the outcome of appraisals.