San Andreas Fault Lidar Point Cloud and Digital Elevation Models

Northern California's San Andreas fault zone is mapped via airborne laser swath mapping (ALSM) data. The dataset contains a LIDAR point cloud and two 6-foot grid digital elevation models (highest-surface and bald Earth). NASA and the USGS collaborated on the acquisition, with data collected in 2003.

Use Cases

• Analyze fault scarp geometry and offset using the bald Earth DEM elevations.
• Model vegetation canopy height by comparing highest-surface DEM and bald Earth DEM grid cell values.
• Assess vertical accuracy of LIDAR-derived topography by comparing DEM elevations to the 85 GPS ground control points.
• Study urban or natural feature reflectance by examining undefined grid cells in the highest-surface DEM associated with water or fresh asphalt.
• Create terrain visualizations using the provided shaded relief images with specified illumination parameters (azimuth 225°, elevation 60°).

Strengths

• DEM vertical accuracy of 17 cm RMSE validated against 85 GPS ground control points.
• Data acquired with nominal density of 1 laser pulse per square meter and 58% swath overlap for redundancy.
• Provides multiple derived products: raw point cloud, highest-surface DEM, and vegetation-removed bald Earth DEM.

Limitations

• Bald Earth elevations under dense vegetation or for water bodies have lower accuracy due to sparse laser returns.
• Dataset is from a single acquisition in 2003 and may not reflect recent tectonic or geomorphic changes.
• Grid cell values are in international feet referenced to NAVD-88, requiring unit conversion for metric analysis.

Provenance

Source

NASA Solid Earth and Natural Hazards Program and United States Geological Survey, acquired by TerraPoint, LLC.

Collection Method

Airborne LIDAR using a discrete-return, scanning laser altimeter capable of up to 4 returns per pulse.

Time Range

2003

Freshness

null

Geography

San Andreas fault zone in northern California, USA, mosaicked by USGS 7.5-minute quadrangles.