Geographical Data

Geospatial Databases

NARAC utilizes extensive global geospatial databases of terrain elevation, land-use, and building footprints. Population data are used to estimate the number of people potentially affected by a particular contamination or dose level. The operational modeling system automatically selects and extracts the appropriate data so that simulations use the finest resolution data appropriate to the calculation.

  • Terrain elevation databases are obtained from several agencies including the US Geological Survey (USGS), the National Geophysical Data Center (NGDC), the National Aeronautics and Space Administration (NASA), the National Geospatial-Intelligence Agency (NGA) and Oak Ridge National Laboratory (ORNL).
  • Population density data are provided by ORNL and include night and day variations. NARAC's population databases also can be adjusted manually to account for large numbers of additional people attending a special event.
  • Building footprint and morphology data provided by NGA, Department of Homeland Security/Federal Emergency Management Agency (DHS/FEMA), Lawrence Berkeley National Laboratory (LBNL) and the US Census Bureau are used for building-scale flow and dispersion model simulations, estimates of indoor air infiltration, and calculations of building protection / shielding factors.
  • Maps and aerial/satellite imagery obtained from the USGS, the National Imaging and Mapping Agency (NIMA), the U.S. Census Bureau, and commercial companies are provided with NARAC plume predictions.