Saco Bay, ME (N110) Bathymetric Digital Elevation Model (30meter resolution) Derived From Source Hydrographic Survey SoundingsCollected by NOAA

Bathymetry for Saco Bay was derived from five surveys consisting of 13,108soundings. No surveys were omitted. The average separation betweensoundings was 61 meters. One survey in the north dated from 1923. The otherfour surveys dated from 1946 to 1955. The total range of sounding data was 3.0meters to -32.3 meters at mean low water. A mean high water value of 2.7meters was assigned to the shoreline. Nine points were found that were notconsistent with the surrounding data. These were removed prior to tinning. DEM grid values outside the shoreline (on land) were assigned null values (-32676).Saco Bay has four 7.5 minute DEMs and a single one degree DEM. The 1degree DEMs were generated from the higher resolution 7.5 minute DEMswhich covered the estuary. A Digital Elevation Model (DEM) contains aseries of elevations ordered from south to north with the order ofthe columns from west to east. The DEM is formatted as one ASCIIheader record (A- record), followed by a series of profile records(B- records) each of which include a short B-record header followedby a series of ASCII integer elevations (typically in units of 1centimeter) per each profile. The last physical record of the DEM isan 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.