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Data associated with the investigation of suitable habitat for the endangered plant Harperella (Ptilimnium nodosum Rose) in the Potomac River near Hancock Maryland

November 6, 2020

In lieu of a uniform mapping of the Chesapeake and Ohio Canal National Historical Park corridor at very high-resolution using UAS, this study developed a multi-scale workflow, where (1) geospatial modeling methods and (2) historic image analysis were used to constrain the areal extent of (3) detailed field and unmanned aerial systems (UAS) observation. Geospatial Modeling Methods: Harperella habitat characteristics reported by literature sources and corroborated by extremely limited harperella occurrence data (in the form of GPS locations), were compiled into a geospatial prediction model (GPM) to characterize the extent of harperella habitat for the region between Sideling Hill Wildlife Management Area and Harper's Ferry National Park. Historical Image Analysis: Analysis consisted of visual examination and manual delineation of in-channel bars within the Potomac River and its larger tributaries, including the Cacapon River, lower Tonoloway Creek, Sleepy Creek, lower Lick Run, and Back Creek. This manual delineation was conducted for several dates of historic aerial imagery, including 2009, 2011, 2013, 2016, and 2017. Persistence of different parts of the in-channel bars over time was mapped by intersecting the 5 years of interpretations. UAS image acqusition of AOIs: UAS imagery was collected to facilitate detailed observation, terrain modeling, and documentation of 10 AOIs (shown in figure). National Park Service regulations restrict the take-off and landing of UAS on park property, so the edge of in-channel bars within the Potomac River was used to enable line-of-sight UAS image acquisition covering the entire AOI. The USGS and the Aerial Vision Group, LLC sought permission to fly a small UAS from both the Maryland and West Virginia Department of Natural Resources (DNR). DEM and Orthophoto datasets are available by request - please email

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