Creating interactive visualisations to make sense of city data

Mirko Marras, Matteo Manca and David Laniado
Monday 6th November 2017

The problem with the current model of data silos and data centralisation in the hands of a few corporations  is not only that citizens’ data are often used for goals they are not aware of. We are also missing opportunities for leveraging such data for public good and individual or collective goals which are not of primary interest for the companies which own  the data.  Furthermore, even when open data are available, they often remain just raw data, which citizens without technical skills cannot benefit from.

DECODE’s vision of data as a common good implies a democratisation of data processing and exposure, based on transparent algorithms and intuitive interfaces for information visualisation and exploration. With this in mind, the DECODE platform will be deployed through four pilots in Amsterdam and Barcelona. In the Barcelona pilots, we are currently working to make data not only available to citizens, but also useful to them. To this end, in the Digital Humanities team at Eurecat, we are developing data analysis and visualisation interfaces to allow citizens to explore data about specific city relevant issues. While individual citizens’ data shared through the DECODE platform are not yet available, in this first phase we have started to work with open data from the city.

In recent years, several of Barcelona’s providers and platforms have given access to an increasing amount of data through publicly-available APIs (Application Programming Interfaces) as well as periodic batch processes. For the purpose of putting this pilot into practice, in collaboration with the Barcelona City Council, we are collecting, integrating, analysing and visualising information extracted from temporal and geo-tagged data coming from the following heterogeneous sources:

  • IRIS  (Incidències, Reclamacions i Suggeriments), an online registry of incidents, complaints, suggestions, and gratitudes of citizens to the City Council;

  • ASIA (Aplicatiu de Sistemes Integrats d’Atenció), an online registry of the activities happening in the City Council’s buildings;

  • Sentilo, an open source platform providing real-time access to Barcelona’s sensors data.

As a first preliminary example, we have started from the consideration that living in a large city like Barcelona means becoming intimately acquainted with the noise generated by transport, industry, people, social events, construction activities and so on. However, such noise is not equally distributed across neighbourhoods. Therefore, given the importance of noise as a source of information about citizens’ and city quality life, we have designed a preliminary visualisation showing a time-evolving map of environmental acoustic levels based on data provided by more than 40 outdoor sensors spread all over the city. The measurements have been collected from Sentilo through Smart Citizen, a platform aimed at building open indicators and collaboratively connecting data, people and knowledge.


The visual interface exposes temporal patterns over the acoustic level measured in A-weighted decibels (dBA) between Monday, October 2nd, and Sunday, October 8th 2017. Hotter colours represent higher levels of noise, while colder ones depict more peaceful acoustic levels. Playing with the controls to start and stop the data animation over a range of time, it is possible to recognize both daily and weekly patterns characterising different neighbourhoods, and to identify for example the areas of the city that are more affected by noise pollution during the night or the weekend.

This visualisation is just a preliminary example to show how the value hidden in city data can be extracted to get useful insights and knowledge. In the next months we will go further, developing analyses and visualisation interfaces to help citizens make sense of the increasing range of data coming from people, sensors, devices and the city.