This report documents part of the National Park Service (NPS)/U.S. Geological Survey (USGS)/National Aeronautics and Space Administration (NASA) Aerial Data Collection and Creation of Products for Park Vital Signs Project. This report is one in a series that describes methods for extracting topographic features from aerial survey data as part of a joint project among the NPS Inventory and Monitoring (IM) Program, the NASA Observational Sciences Branch, and the USGS Center for Coastal and Watershed Studies (CCWS).