Sheepscot Bay, ME (N080) Bathymetric Digital Elevation Model(30 meter resolution) Derived From Source Hydrographic SurveySoundings Collected by NOAA

Bathymetry for Sheepscot Bay was derived from nineteen surveys containing173,929 soundings. One survey was omitted before tinning the data. Theaverage separation between the soundings was 25 meters. The nineteensurveys used dated from 1941 to 1943. The total range of soundings data was2.0 meters to -81.4 meters at mean low water. Mean high water values of 2.7 or2.8 meters were assigned to the shoreline. Seventeen points were foundthat were not consistent with the surrounding data. These were removedprior to tinning. DEM grid values outside the shoreline (on land)were assigned null values (-32676).Sheepscot Bay has five 7.5 minute DEMs and a single one degreeDEM. The 1 degree DEMs were generated from the higher resolution 7.5minute DEMs which covered the estuary. A Digital Elevation Model(DEM) contains a series of elevations ordered from south to northwith the order of the columns from west to east. The DEM isformatted as one ASCII header record (A- record), followed by aseries of profile records (B- records) each of which include a shortB-record header followed by a series of ASCII integer elevations(typically in units of 1 centimeter) per each profile. The lastphysical record of the DEM is an accuracy record (C-record).The 7.5-minute DEM (30- by 30-m data spacing) is cast on theUniversal Transverse Mercator (UTM) projection. It provides coveragein 7.5- by 7.5-minute blocks. Each product provides the samecoverage as a standard USGS 7.5-minute quadrangle but the DEMcontains over edge data. Coverage is available for many estuaries ofthe contiguous United States but is not complete.