For the 30th edition of Amsterdam Dance Event, artist Bob de Jong gave Amsterdam a heartbeat that can only be heard from orbit. Terramira placed the radar reflectors on the city’s rooftops and processed the satellite images that became the beat.
Beat of the City launches on 21 October, at the opening of ADE. The film shows Amsterdam the way a radar satellite sees it, then lets the city pulse. Behind the art sits the work we do every day: comparing satellite observations over time and making visible what changed.
Amsterdam Dance Event turns 30. Beat of the City was made for the anniversary. It premieres at the opening.
Amsterdam artist. He gave the city a heartbeat that can only be heard from orbit. Radar images, rhythm and electronic sound became one film.
The Dutch voice in ESA. Co-responsible for the technology in orbit, including the Sentinel-1 radar satellites. Without them, no beat.
We turn satellite data into intelligence on what changes on Earth. For ADE, we placed the reflectors and processed every pass. The beat is change, detected from space.
How a radar satellite sees a city
The project uses the European Sentinel-1 satellites, which observe the Earth with Synthetic Aperture Radar (SAR) from roughly 700 kilometres up. A radar satellite doesn’t take photographs. It sends microwaves down and records what each surface sends back. Because it brings its own signal, it works at night and straight through cloud.
What comes back depends on the surface. Smooth water reflects the signal away from the satellite, so Amsterdam’s canals appear dark. Buildings and other structures send much of it back and light up. The strength of each echo is expressed in decibels, the same unit used for sound. For a project about electronic music, that was a useful coincidence.
Making the city answer
Rather than simply observing the city, we adapted the city to be observed. Together with Sensar, our team placed aluminium corner reflectors on the roofs of Felix Meritis and the A’DAM Tower.
A corner reflector is three metal plates set at right angles. A radar signal that enters it is sent back towards where it came from. On a rooftop, that makes the reflector a bright, recognisable point in the radar image, far stronger than the roof around it. To get that effect, each reflector has to be positioned and aligned with the satellite’s viewing direction.
The two locations were chosen for their story. Felix Meritis has an 18th-century observatory and today hosts the ADE Pro conference. The A’DAM Tower looks out over the IJ as an icon of contemporary electronic music culture. More than two centuries ago, people studied the sky from Felix Meritis. Now satellites look back.
From radar echo to rhythm
The satellites return over Amsterdam on their own observation rhythm, and every pass produces a new radar image. We processed those passes the way we process radar data for our clients: calibrated, aligned and placed in sequence, so that each image can be compared with the one before.
Between passes, most of the city stays the same. The reflectors don’t. Against that still background, their bright points read as a pulse. The beat in the film is, quite literally, a change between observations.
Bob de Jong turned that sequence into an audiovisual composition of raw radar images, signal patterns, rhythmic editing and electronic sound design. The film moves from Amsterdam’s night-time energy to the view from orbit and ends in the electronic heartbeat of the city.
The same principle, every day
Take away the music and what remains is the core of our work. We compare satellite observations over time to see what changed on the ground, and translate that into information people can act on. That might be a change in buildings and infrastructure, in water, or in trees and green space. Radar adds something optical imagery can’t: a reliable view at night and under the cloud cover the Netherlands knows so well.
“Radar satellites keep returning over Amsterdam, day and night, straight through the clouds. We turn those signals into insights about buildings, infrastructure, water and nature, helping organisations make better-informed decisions. We often think of Earth observation as a tool for understanding the world. Beat of the City invites us to appreciate it as something beautiful in its own right. That’s what Earth Intelligence means to us: revealing our changing world, so we can help shape a better one.” Reinier Oost, Earth Intelligence Lead at Terramira
See it during ADE
The film launches online on Wednesday 21 October. During ADE, visitors can see the radar reflector on the roof of the A’DAM Tower, together with the film.
Beat of the City is an art project by Amsterdam artist Bob de Jong, created for the 30th anniversary of Amsterdam Dance Event, in collaboration with the Netherlands Space Agency and Terramira.
