UGRC is in the process of finalizing a contract with Watershed Sciences Inc. (WSI), opens in a new tab to acquire 1,352 square miles of USGS Quality Level 1 Lidar elevation data in the Fall of 2013. WSI won a competitive bid process this summer, that attracted 7 vendor submissions, for a project area that includes: the urbanized areas of the Salt Lake and Utah Valleys and areas along the Wasatch Fault from Sanpete County north into Onieda County in southeastern Idaho.
Lidar stands for Light Detecting and Ranging. Lidar data is collected using an airplane-mounted laser and a sensor that records the laser pulse reflections from surfaces on/near the ground. The timing of the pulse returns provides a surrogate for measuring distance. When the distance measurements are combined with the precise instantaneous position of the aircraft from its onboard GPS, the elevation and position of surface of the earth, structures, and vegetation can be measured with high precision.
Quality Level 1 is currently the ‘Cadillac’ data specification for Lidar as it provides the highest level of horizontal and vertical exactness, as well as multiple measures from the same square meter, enabling among other things, structures and ground surfaces to be measured through tree canopies.
The primary intended uses for the new Lidar data include but are not limited to:
- Planning, preparing & mitigating flooding hazards through FEMA’s Risk Map, opens in a new tab modernization program
- Detailed detection of earthquake faults and related hazard modeling and vulnerability studies
- Delineation of building and structure footprints for general purpose mapping
Many other non-traditional uses of Lidar data are possible such as detecting landslides and slumping, optimizing irrigation, and quantifying solar energy systems potential, opens in a new tab on rooftops and other surfaces.
The 2013 Lidar acquisition is funded through a partnership of the US Geological Survey, opens in a new tab, Utah Geological Survey, opens in a new tab, Utah Division of Emergency Management, opens in a new tab, FEMA, and a consortium of local government led by the Salt Lake County Surveyor’s Office, opens in a new tab. Flights are expected to begin mid Fall, weather conditions permitting, and data delivery is anticipated several months after the flights are completed.
Project deliverables include:
- Raw Point Cloud
- Classified Point Cloud (8 points per square meter with 9.25cm vertical RMSE)
- Bare-Earth Digital Elevation Model (DEM) (0.5 meter cell size with 9.25cm vertical RMSE and Hydro-Flattening)
- First Return Surface Model (0.5 meter cell size)
- Intensity Images (0.5 meter resolution GeoTIFFs)
- FGDC Metadata