Grand Bay National Estuarine Research Reserve and U.S. Department of Agriculture National Agriculture Imagery Program (NAIP)
Location
Grand Bay National Estuarine Research Reserve, Mississippi/Alabama
Summary
Data was collected by the Grand Bay NERR as GPS points and provided to the USGS SPCMSC. USGS researchers converted the points into lines and ran the shorelines through a shoreline change analysis. Final data is published as a U.S. Geological Survey data release, https://doi.org/10.5066/P9JMA8WK.
Info derived
GPS shorelines (2013-2020), Site description and elevation profiles (2020)
Comments
GPS data were collected using a Trimble R8 Model 3 Global Navigation Satellite System (GNSS) and TSC3 data collector from 2013 to 2018, or a Trimble R10 GNSS system and TSC3 data collector from 2018 to 2020. Each were attached onto a 2-m graphite rod with a mounted foot to obtain both horizontal and vertical shoreline position. The positional accuracy of Trimble R8 Model 3 GPS points was ± 10 millimeters (mm) + 1 parts per million (ppm) root mean square (RMS) horizontal error and ± 20 mm + 1 ppm RMS vertical error. The horizontal error of the Trimble R10 GPS points was ± 8 mm + 0.5 ppm RMS and vertical error was ± 15 mm + 0.5 ppm RMS. The shoreline points were collected along the vegetation-water boundary, which typically represented the top of an erosional scarp; where an erosional scarp was not visible, the most suitable shoreline position based on dense shoreline vegetation is mapped. For the transects with site descriptions, each transect consists of two points on the marsh platform, one at the top of the scarp (or estimated top if no scarp was present), bottom of the scarp (or estimated bottom if no scarp was present) and one point in the nearshore estuary.
