Realtime Weather Sonification

OpenWeatherMap

This first, simple Web Audio sonification application makes use of the Weather API for real-time, browser-based sonification of weather data. For fetching data, a free subscription is necessary: https://home.openweathermap.org

Once subscribed, the API key can be used to get current weather information in the browser:

https://api.openweathermap.org/data/2.5/weather?q=Potsdam&appid=eab7c410674e15bfdd841f66941a92c2

JSON Data Structure

The resulting output in JSON looks like this:

{
  "coord": {
    "lon": 13.41,
    "lat": 52.52
  },
  "weather": [
    {
      "id": 804,
      "main": "Clouds",
      "description": "overcast clouds",
      "icon": "04d"
    }
  ],
  "base": "stations",
  "main": {
    "temp": 9.74,
    "feels_like": 6.57,
    "temp_min": 9,
    "temp_max": 10.56,
    "pressure": 1034,
    "humidity": 93
  },
  "visibility": 8000,
  "wind": {
    "speed": 4.1,
    "deg": 270
  },
  "clouds": {
    "all": 90
  },
  "dt": 1604655648,
  "sys": {
    "type": 1,
    "id": 1275,
    "country": "DE",
    "sunrise": 1604643143,
    "sunset": 1604676458
  },
  "timezone": 3600,
  "id": 2950159,
  "name": "Berlin",
  "cod": 200
}

All entries of this data structure can be used as synthesis parameters in a sonification system with Web Audio.

Temperatures to Frequencies

Mapping

In this example we are using a simple frequency modulation formula for turning temperature and humidity into more or less pleasing (annoying) sounds. The frequency of a first oscillator is derived from the temperature:

\(\displaystyle f_1 = 10 \frac{1}{{T^2 / C^{\circ} }}\)

The modulator frequency is controlled by the humidity \(H\):

\(y = sin(2 \pi (f_1 + 100 \cdot \sin(2 \pi H t))t)\)


The Result

The resulting app fetches the weather data of a chosen city, extracts temperature and humidity and sets the parameters of the audio processes:

Where would you rather be?

What does the weather sound like in ...?





Contents © Henrik von Coler 2021 - Contact