For the past two years, Nic Roets, a local investor and programmer, has ridden his bicycle from Pretoria to his sister’s home in Johannesburg. With him, he takes a handheld GPS device that records his routes on different back roads to which he adds road names, security road closures and other data.

Back home, he uploads the data to OpenStreetMap.org, an open source project to produce detailed streetlevel maps that can be published freely on sites such as Wikipedia, used to create handheld or in-car navigation devices, or printed and copied without restriction. Why has Roets ridden about 100km a week for more than two years for a project that gives away this data for free? And why is this softly spoken programmer from Pretoria (and his 130 000 collaborators around the world) causing so many mapping companies to feel threatened as location based data goes open?