Where the roads aren't - and why it matters

Editor's note: Last week we published a series of blog posts about our activities at Rio+20, the United Nations Conference on Sustainable Development. The post below is by Rebecca Moore, manager of the Google Earth Outreach team.

We were excited to unveil at the Rio+20 Conference the initial fruits of a unique collaboration with a member of the European Parliament and the Society for Conservation Biology: a global, interactive map of the world’s “Roadless Areas.”

The project came about when we were approached by MEP Kriton Arsenis, the European Parliament's Rapporteur on forests. He explained that, while most people using Google Maps want to know which roads will get them from point A to point B, the same information is useful for conservationists who want to know where roads aren’t. In his words:

The concept of "roadless areas" is a well-established conservation measure coming from conservation biologists from all around the globe. The idea is that roads in most parts of the world lead to the unmanageable private access to the natural resources of an area, most often leading to ecosystem degradation and without the consent of the local and indigenous communities. Keeping an area roadless means that the specific territory is shielded against such exogenous pressures, thus sustaining its ecosystem services at the maximum possible level. An important tool which will drive environmental, development as well as global climate change policy forward will be the Google development of an interactive satellite map of the world's roadless areas.

We were intrigued by Kriton’s idea, so we decided to give it a try.

Start with where the Roads are

We started by taking all the road data (plus rail and navigable waterways) in Google Maps today, and importing that into our Google Earth Engine platform for analysis. For example, here is what the road network in Australia looks like when zoomed out to country-scale:


Then figure out where the roads aren't

Based upon advice from Kriton Arsenis and his project collaborators in the Society for Conservation Biology, we decided to define a “Roadless Area” (for the purposes of this prototype map) as any area of land more than ten kilometers from the nearest road. Using the global-scale spatial-analytic capabilities of Google Earth Engine, we then generated this raster map, such that every pixel in the map is color-coded based on distance from the nearest road. Every pixel colored green is at least 10km from the nearest road, and therefore considered part of a Roadless Area. For example:


Or consider the island of Madagascar, home to some of the most unique species on Earth:


From these maps it becomes more apparent how the simple construction of new roads can fragment and disturb habitats, potentially driving threatened species closer to extinction.

Finally we decided to try running this “Roadless Area” algorithm at global-scale:


Large roadless areas are readily apparent such as the Amazon and Indonesian rainforests, Canadian boreal forest and Sahara desert.

Caveats and Next Steps

The road data used to produce these maps inevitably contains inaccuracies and omissions. The good news is that Google already has a tool, Google Map Maker, that can be used by anyone to submit new or corrected map data, and in fact this tool is already being used in partnership with the United Nations to support global emergency response. We look forward to continued development of this prototype, which can help to turn the abstract concept of “Roadless Areas” into something quite concrete and, we hope, useful to policymakers, scientists and communities around the world. To explore these Roadless Area maps yourself, visit the Google Earth Engine Map Gallery.

Posted by Rebecca Moore, Manager, Google Earth Outreach and Google Earth Engine