2023 Shortlist

How much has your hometown grown since you were born?

Entry type: Single project

Country/area: Spain

Publishing organisation: elDiario.es

Organisation size: Big

Publication date: 2022-01-16

Language: Spanish

Authors: Raúl Sánchez


Raúl Sánchez: Spanish data journalist covering stories of inequality, gender, health, taxes and urbanism at elDiario.es. He coordinates elDiario.es data team.

Project description:

A journalistic project that analyzes the footprint and year of construction of more than 12 million buildings throughout the country to map how the urban landscape of Spanish cities has changed in the last century. The investigation was published as a personalized article where the reader could select their year of birth and the texts and graphics of the piece are adapted to it. This way, every user will read their own and unique story.

Impact reached:

This project compiled for the first time in a single database the cartographic plans of all the buildings currently standing throughout the Spanish territory. The map, which can be consulted by all readers, allows at a glance to understand and explain how Spanish cities have grown in the last century. The innovative format allowed readers to explore the heights of their buildings in three dimensions and also what it’s the age of their own house while we explained with personalized graphics and data the urban decisions that were made in each decade, along with the socioeconomic context of each moment. This story explored for the first time in Spain the personalization of the content based on the age of the reader: not only graphics but also part of the text is modified based on the year of birth selected by the user.

This project has proved that innovative narratives are useful and welcomed by elDiario.es users. The publication has been viewed by more than 200.000 users and it was one of the most read of the year in elDiario.es and also one of the articles that made most people suscribe and pay for elDiario.es during the year, according to our statistics. Added to this, the publication doubled the average time of view of a usual article in elDiario.es. It was also selected by the Global Investigative Journalism Network in his weekly TOP10 Journalism projects.

This sister project “Spain Lives in Flats”, published in 2021, won the Royal Statistical Society Award for Statistical Excellence in Journalism, a bronce medal at Information is Beautiful Awards and data visualization category at Digital Media Awards Worldwide (Awards), among other prizes.

Techniques/technologies used:

R, Rstudio, QGIS and Tippecanoe for data compiling and data analysis. D3.js and Javascript for data visualization. Mapbox for mapping buildings footprint. HTML and Javascript for personalized content and connected events.

Context about the project:

The hardest part of the project was compiling and automating the download of the building footprint of more than 12 million buildings throughout Spain and processing that amount of information. We created an R script that downloaded cadastral data of the buildings of more than 7,600 municipalities, one by one. The total size of the downloaded files exceeded 200GB on hard disk. During the processing of the data, the journalists found errors in the files that were later corrected after notifying the cadastral institution.

Then, we processed and joined in R all downloaded files to have a single database with the details of all the buildings in Spain. For example, we verified the data of 12 million buildings, we calculated the height of every building from the part that occupies the most built volume in the plans and we extracted the date of the building from the start of construction. All these processes were repeated several times during the year due to the publication of corrections and allowed us for the first time in Spain to have a database with the age of construction of all the buildings in the country.

In addition, Tippecanoe was used with different configurations to reduce the size of the files and thus be able to work with it in Mapbox.

What can other journalists learn from this project?

This project shows how the information available in national cadastres could be exploited in other countries to explain the urban planning of each territory and to tell stories of how other cities were built. The page format and personalized visualization are also part of one of elDiario.es’ long-term bet to give their readers informative content in innovative format by promoting collaborative work between traditional journalists and the data and visualization team.

Project links: