Mobile Coverage Explorer is a representation of the area covered by mobile networks around the world. It is supplied as vector and raster data which has been created from submissions made directly to Collins Bartholomew or the GSMA from network operators who provide roaming detail for inclusion in the GSMA’s Network Coverage Maps web application. This data is supplemented with coverage created from OpenCellID, the world's largest open database of cell towers. Mobile Coverage is released annually in January each year. Title supplied by cataloger.