Railroads and US Population Growth

A decentennial (every 10 years) census is required by the US Constitution, and to date 24 have been completed, with the first in 1790 and the most recent in 2020.

When animated on a map, this makes up a very interesting time series showing how the US has grown over the past 250 years. But this data doesn’t tell the whole story, because Native Americans and others were excluded from counts.

There are two datasets on the map:

• The first is historical population data from the US Census (via UMich ICPSR). It was joined with county polygons.
• The second is historic US railroad network data, from Jeremy Atack at Vanderbilt. This data was ‘exploded’ so that each row was a railroad, and there was a ‘year’ column that indicates it was present in that year.

In Honeycomb, a polygon layer was added to show counties, colored by population with a fixed value to color mapping (so the colors stay fixed as the years change). Additional layers show percent change and absolute change. Filtered metrics were added showing the year and total population.

The historical railroad route data was added to the map as a line layer. A timeline slider filters both the population polygons and the railroad network data.

Everything on the map is rendered in real-time within the browser from raw data, at every animation frame - there’s no pre-computation of data going on.

The effect is that you can see the simultaneous and inter-related growth of the US rail network and population through the 1800s.