Here at TheCityFix, we’ve watched the open data movement virtually explode in recent years.

Having comprehensive, transparent data allows both civil society and government to utilize critical information to make cities better places to live. On one hand, local governments and transport authorities are in a position to collect data about travel behavior, assess the efficiency of their services, and improve transport systems based on insightful analysis of that data. On the other hand, social entrepreneurs, non-profits, and civic activists—really, anyone who loves their city—can tap into the potential of open data to develop innovative technologies, enhance existing social programs, and change how we interact with each other and our cities.

That’s why we’re excited about tomorrow’s Open Data Day, a hackathon hosted and supported by the Open Knowledge Foundation. On February 21, 2015, people from around the world will come together for a day-long “hackathon” to develop new apps, create engaging visualizations, and publish thought-provoking analyses using governmental data that’s been made available to the public. Organizers hope that the event’s end products will encourage local, regional, and national governments to invest in accurate data collection and support open data policies.

Organizing from the ground up

Open Data Day participants are encouraged to meet up with others in their cities and collaborate as a group. So far, 105 cities have formed groups. While prominent tech hubs like London and Washington DC are well represented, hackers globally have teamed up in places like Kolkata, India and Nairobi, Kenya to work together in cities that don’t usually make headlines for civic innovation.

Successful hackathons draw on the insights and expertise of people from a variety of disciplines, and Open Data Day’s organizers call on developers, designers, librarians, statisticians, and interested citizens to get involved. The idea is to include a diversity of voices, opening up the range of possibilities that can result from collaboration. As long as groups engage open data in some way, they can pursue any kind of project they want.

At the end of the day, organizers are urging groups to put together at least one demo, proposal, or prototype that they can share with the global community. One of the main purposes of the event is to spur communication and interaction across geographic lines. While it’s true that cities often face their own unique challenges, they also can learn a lot from each another’s experiences. Open Data Day’s impact is both local and global.

Open data is starting to make a concrete difference

In recent years, open data has progressed from a concept advocated by a few fringe developers to a mainstream movement with an increasingly tangible impact. A handful of Brazilian cities, for example, are embracing open data to encourage public participation in civic life. Crowdsourcing platforms, like São Paulo’s VGI (Volunteered Graphic Information) system, are providing cities with valuable information about citizens’ needs and concerns. And in London, transport authorities are using big data to make public transport more efficient, resulting in travel time savings of $23 – 90 million annually.

But data needs to be comprehensive and transparent to the public if city leaders want to unlock its full potential. Equipping individuals and the private sector with accurate information about their city is indispensable to creating an inclusive civic society in which both the government and the public actively contribute together to bettering their communities. After all, regardless of the end results of Open Data Day, the event’s organizers hope that the hackathon will serve as a meaningful gesture to local and national governments that open data matters to their citizens. Anyone can make a difference in in their city as long as they have access to the right information.