Building traffic 🚚 maps with Space data 🛰️
A quick tutorial to generate traffic maps and understand impacts of COVID-19 on Europe’s mobility & economy
Road transportation is a good indicator of how the economy of a country is performing. Follow the step-by-step instructions to understand the evolution of trucks on main roads throughout lockdown periods in Europe, using satellite data and an online tool, launched by the European Space Agency and the European Commission.
Step 1 — First things first! Open the tool.
Visit the site: race.esa.int. This free platform consists of a dashboard with several indicators (related to air, land, water, economy and agriculture) monitored using satellite data.
Step 2 — Select the ‘Number of trucks’ indicator
Select the ‘Number of Trucks’ indicator (you can find it via the left panel or by clicking directly on the ‘Global Indicators’ button as shown in the picture). A map with the averaged number of trucks (aggregated in a period of three months) will appear on the right visualization panel.
The detection of trucks and their averaged numbers was derived using the Copernicus Sentinel-2 data, at the end of the tutorial you will find more details on how this information was extracted from optical data. The truck indicator shows if there has been a low or high number of trucks on primary roads and highways within the respective region of interest.
Step 3 — Draw your area of interest
For an easier exploration, enlarge the map (clicking on the arrows on the upper left corner of the truck map). Under the zoom buttons, click on the polygons and draw a polygon over your area of interest. In the example below, we select a rectangle-shaped area over the city of Paris.
Step 4 — Extract information!
On the top of the map you can either select motorways or primary roads. As you zoom in and out the average numbers get segregated or aggregated respectively, to the location. The maximum zoom will actually show the location of the detected truck — but bear in mind this is information relative to a period of 3 months.
You can also compare this time of period to past years to further understand if there are changes (and what is the magnitude) relative to post-pandemic truck activity on the European roads.
Step 5 — Share your results!
Lockdown measures have been diverse across the EU both in duration and intensity. What were the impacts on the main motorways or primary roads across the main European cities? Explore, find the answer and share it with the Twitter account @EO_OPEN_SCIENCE.
…How are the trucks detected?
The method exploits an effect related to the Sentinel-2 Multispectral Instrument (MSI) geometry. Sentinel-2 does not see a moving truck once but three times in the red-blue-green wavelengths. As the truck keeps traveling during this short time offset, it appears spectrally disassembled. This pattern may be used for detecting roaming trucks on roads. Although visual inspection cannot confirm that the objects are trucks, this is implied by the ratio between size of different vehicles and a Sentinel-2 pixel. The blue dots in the picture below are examples of identified trucks . You can find more information about this methodology developed by Henrik Fisser the winner of the custom script contest.
More on the Rapid Action on coronavirus Earth observation dashboard
The Rapid Action coronavirus and Earth observation — or RACE is an online platform that allows anyone to access data collected from satellites and understand the impacts on societal and economic changes driven by the coronavirus pandemic. This initiative is the result of the Joint cooperation between ESA and the European Commission.
