NCALM. PI: Brian Wernicke, Caltech and Bernard Guest, University of Calgary. The survey area consisted of three 500 meter wide corridors near the California-Nevada border and across the Pahrump Valley. The corridors total approximately 60 km long, 0.5 to 1 km wide and contained approximately 40 square km. Please note that the flight was conducted in an unconventional way as this was an add-on to other work and was done to quickly obtain data for the requested area. Rather than flying a regular, straight grid across the area, the airplane banked along the determined trajectory. This way of gathering data introduces noticeable error, especially on the fringes of the flight path, giving a "corduroy" appearance to the data. This is in addition to the background periodic fine scale elevation variation (normally 5 to 20cm) which is a property of the Optech LIDAR system, and within the machine's error limits. This effect is less noticeable in Corridor 1 as the plane was following a mostly straight trajectory. Our understanding is that if these preliminary data looked promising, a carefully planned survey would then be conducted if funding became available. Bare-earth extraction was not performed on this dataset due to the scarceness of vegetation in the interest area. Filtering the data with a conservative feature preserving algorithm (Hagerud) can remove some of the vegetation but with the expense of smoothing out some of the morphology in steep areas.
Dataset Acknowledgement: Lidar data acquisition and processing completed by the National Center for Airborne Laser Mapping (NCALM - http://www.ncalm.org). NCALM funding provided by NSF's Division of Earth Sciences, Instrumentation and Facilities Program. EAR-1043051.