Batticaloa, Sri Lanka, OSM edits since May 1, 2013 (Open Cities Project and using the HOT Task Manager).
OpenStreetMap edits in Maynooth, Ireland ("Analysing the growth of OpenStreetMap networks" by Corcoran, Mooney and Bertolotto in Spatial Statistics) - densification (red), exploration (green)
That evolution looks an awful lot like how physical street networks themselves evolve over time. And, in fact, the Irish researchers behind this project found that OpenStreetMap expands precisely through two processes – “exploration” at the outer edges of the known network, and concurrent “densification” of its core – that have been used to describe how road networks are built.
Obviously, a new area must be explored before anyone can build out that particular neighborhood’s spiderweb-like side streets. But these two processes occur simultaneously in different parts of the network. Given that OpenStreetMap appears to so closely mirror the growth of real-world infrastructure, the tool may offer the opportunity to understand the expansion of networks in a way that no one was trying to do when these streets were paved in the first place.
Researchers have gone back to look at earlier maps of development. But that process typically involves digging out old paper maps, scanning and digitizing them. And good time stamps aren’t always available to pinpoint a map’s moment in time. But with OpenStreetMap, Corcoran says, “It opens an opportunity to study how networks are growing in real time. OpenStreetMap is currently an evolving process – it’s still not complete. We don’t know when it will reach a stage of maturity.”
gif animation (in gist) of the last seven years of changes to OpenStreetMap based on the changesets grouped into 72 day periods