D i s p l a c e d : R e p l a c e d I I
Images and movies from ICMC 2002, Gøteborg Art Museum
Natasha Barrett:concept, music, visual design, programming
Øyvind Hammer:programming
Kjell Bjørgeengen:visual design and adviser

The Displaced:Replaced project began as a space within which sound is played over a cubic array of loudspeakers. The sound is controlled by real-time weather data using rule-based mapping procedures. In the first version of Displaced:Replaced semi-abstract still photographic images were projected within the space. In Displaced:Replaced II, instead of still images, real-time graphics are controlled in parallel with the sound. The result is a mimetic abstraction of the meteorological source, projected through sound and vision within the space.

By applying a rule-based rather than direct mapping of data and sound, the composer can stand in the centre of the work: on the one hand controlling the installation through composing the sound material and the rules, while on the other hand the weather determines the realised result. Likewise is the case with the visualisation.

The sensors

Custom made sensors (temperature, humidity, light, precipitation, wind direction, wind speed and wind gust) monitor the weather. The sensors each produce a voltage change, which is converted into MIDI information and transmitted over the Internet. The sensors are currently located in Oslo: displacing the local weather conditions and replacing them with those where the sensors are located.


The visual projection is a combination of pre-made images and the real-time physical modelling of weather conditions, including a realistic air flow (wind) model based on the Navier-Stokes equations. Real-time control from weather sensors influences the weighting of velocity fields (wind direction) and the speed of particles in the flow (wind speed and gust).

The background pre-made images are also transformed by the particle system through erosion and deformation processes, as well as being manipulated by other real-time processing algorithms. In addition to the air flow model, the dynamics and appearance of particles and images are controlled by data from the rest of the sensors.


Sound material has been created in stereo and ambisonics sound-files, ranging from one second to two minutes in duration. This material is stored on the computer hard-disk. Up to four 8-channel sounds and eight 4-channel sounds can play simultaneously (depending on how rapidly the weather data varies). The addition of real-time sound transformation results in an infinitely variable sound environment.

The original version of Displaced:Replaced was commissioned by the Ilios Festival and premiered in Harstad, Norway, 2001.

Displaced:Replaced II exhibition at the ICMC2002 is partly funded by the Norwegian department for foreign affairs.