How Detailed Is Your Demographic Data? It Makes a Difference

Demographic Transit Data in the European Union

Open Demographic Data Enhances Mobility

Public transportation authorities around the world use demographic data to analyze and improve mobility in their cities. Here’s a simple example of how overlaying population and jobs data can help analyze who can access the route:

In the video, you can see demographic data at the US census block level, which gives great estimates of population, jobs, and other relevant information.

Different Countries, Different Levels of Detail

However, there are major differences in the level of detail available for different countries’ data. The European Union provides data for population grids of 1 sq km. This is how Europe’s population density looks in Remix:

Population density of the European Union, using 1 sq km grids, zoomed to a 300-km view.

But EU data is just one dataset of hundreds; each country, region, or municipality within the EU typically collects demographic data with its own level of granularity. For example, let’s look at the differences between the open data used in the island nation of Malta and in the UK, both viewed at the same scale (500m):

Population density by census block in Malta (left) and the UK (right). The level of detail of demographic data differs greatly based on location.

Maltese census data is less detailed than the 1 sq km grids provided by the EU, whereas the UK open data is much more detailed than the 1 sq km grids.

Shorter Routes Require More Detailed Data

When it comes to estimating the population affected by a change in the bus system, it is critical for this data to be as accurate as possible. The smaller each section of the map is, the better results we get. In Manchester, there are significant changes when we switch between calculating the EU data of 1 sq km grids and UK data, which is much more detailed:

In general, the EU 1 sq km grids provide results within 90% accuracy on long lines with evenly spaced stops along the route. However, for shorter or irregular routes, the accuracy provided by the 1 sq km grids decreases dramatically, which can make insights drawn from the data unreliable.

Most cities in Europe do have more detailed data than the 1 sq km grids provided by the EU, typically at the city council, regional government, or district level. And even though some of this data might not be open to the public, it is generally made accessible to transit agencies by the country’s Public Transportation Authority upon request.

At Remix, we encourage all transit agencies to use the most detailed data available during their planning process, as it improves accuracy and reliability for the end users of the system — which gets at the main goal of providing mobility to the greatest number of people possible.