County approves contract for 3-D topographic mapping, surface modeling

The San Diego County Board of Supervisors voted 5-0 July 20 to approve a funding agreement between the county and the U.S. Geological Survey (USGS) for three-dimensional topographic mapping and surface modeling of San Diego County.

USGS will use light detection and ranging (lidar) remote sensing technology to map the portions of San Diego County for which data does not currently exist. The high-resolution elevation data will have applications for studies focusing on infrastructure or the environment.

"Introducing this new modeling data into the county's mapping systems will allow us to make more informed land use decisions and provide an increased level of service to residents," said Supervisor Bill Horn.

The county will fund $133,000 of the project for USGS to acquire the lidar mapping data while the San Diego Association of Governments (SANDAG) will contribute $255,170. SANDAG oversees the San Diego Regional Geographical Information System (SANGIS) council, which in 2014 led the 27-agency Imagery Acquisition Partnership Project to fund the mapping of 1,388 square miles of coastal and urban areas in San Diego County.

The Federal Emergency Management Agency provided funding in 2015 for the mapping of 1,600 square miles of unincorporated San Diego County for the purposes of supporting the county's flood impact modeling activities. The total area of San Diego County is 4,526 square miles and is comprised of 4,207 square miles of land and 319 square miles of water.

The County of San Diego currently relies on 30-year-old topographic maps for elevation data and the current data has spatial resolution of 33 square feet. The USGS lidar data will have a resolution of two square feet. The county expects to use the data for hazard mitigation, conservation, infrastructure development, and regional security and may also determine other applications.

The county and USGS expect the mapping and modeling to be complete by September 2017.