Fig. 4
From: Open source data mining infrastructure for exploring and analysing OpenStreetMap
Calendar heat map with temporally arranged cells. Yellow colour indicates a low number of nodes/users per day, blue colour indicates a high number. In case no data were available for a day, the cell is left white. Data from OSMStats Ⓒ OpenStreetMap contributors (cf. www.openstreetmap.org/copyright). a New nodes per day b New users per day