View Metadata As: Get Data, FAQ, HTML, 19139 XML

Assess Metadata For: Completeness, DOI Readiness, CSW Readiness, Components
Penobscot Bay, ME (N050) Bathymetric Digital Elevation Model (30 meter resolution) Derived From Source Hydrographic Survey Soundings Collected by NOAA
Bathymetry for Penobscot Bay was derived from forty-three surveys containing 477,888 soundings. Nine entire older, less accurate, overlapping surveys and the overlap from five older less accurate surveys were omitted before tinning. The average separation between soundings was 46 meters. Four of the surveys in the southeast and east dated from 1869 to 1883. The other thirty-nine surveys dated from 1944 to 1985. The total range of soundings was 4.0 meters to -164.9 meters at mean low water. Mean high water values between 2.8 and 4.1 meters were assigned to the shoreline. Twenty-two points were found that were not consistent with the surrounding data. These were removed prior to tinning. DEM grid values outside the shoreline (on land) were assigned null values (-32676). Penobscot Bay has twenty 7.5 minute DEMs and two one degree DEMs. The 1 degree DEMs were generated from the higher resolution 7.5 minute DEMs which covered the estuary. A Digital Elevation Model (DEM) contains a series of elevations ordered from south to north with the order of the columns from west to east. The DEM is formatted as one ASCII header record (A- record), followed by a series of profile records (B- records) each of which include a short B-record header followed by a series of ASCII integer elevations (typically in units of 1 centimeter) per each profile. The last physical record of the DEM is an accuracy record (C-record). The 7.5-minute DEM (30- by 30-m data spacing) is cast on the Universal Transverse Mercator (UTM) projection. It provides coverage in 7.5- by 7.5-minute blocks. Each product provides the same coverage as a standard USGS 7.5-minute quadrangle but the DEM contains over edge data. Coverage is available for many estuaries of the contiguous United States but is not complete.