Colombo is the largest city in Sri Lanka by population and economic activity. With the post-‐war infrastructure boom, land use patterns in Colombo are changing quickly, with residential population continuously decreasing making way for commercial activities. Having an up-‐to-‐date overview of land use characteristics is critical in for urban planning, and traditional survey and census-‐based methods in addition to being expensive cannot give high-‐frequency insights. Mobile network big data could be utilized as a low-‐cost and high frequency alternative for understanding changes in land use. Our method potentially goes further than previous efforts, by allowing for a more fine-‐grained understanding of land use changes.

Whenever a mobile phone is used to make or receive a call or SMS, or to access the Internet, the event is captured via meta-‐data stored in the operator’s logs. This is called a Call Detail Record(CDR). The CDR also contains the location of the Base Transceiver Station(BTS) that services the subscriber, as well as timestamp for the event. Using these records it is possible to get a time-‐series of activity at each BTS. Building on prior work [1, 2, 3, 4], this usage pattern of BTS activity can be leveraged to understand the characteristics of the land beneath it.