Produced and updated annually by the Oak Ridge National Laboratory (ORNL), LandScan is global population distribution database featuring population estimates at approximately 1 km resolution (30 arc-seconds) and representing an ambient population averaged over 24 hours. Like tabulated census data, the LandScan dataset represents population counts, but it presents census counts disagreggated within administrative boundaries through the use of spatial data, imagery analysis, and a multi-variable dasymetric modeling approach that incorporates physical, socieconomic, and cultural understandings of areas. LandScan was first produced in 1998 for the U.S. Department of Defense to estimate populations at risk. It continues to be used in rapid consequence and risk assessment and for emergency planning and management.