Summary

Description

Bathymetry for Charlotte Harbor was derived from twenty-two surveyscontaining 256,940 soundings. No surveys were omitted. The averageseparation between soundings was 55 meters. The surveys datedfrom 1955 to 1961 with approximately 50 percent from 1955 or 1956.The range of sounding for the surveys was 1.2 meters to -22.3meters at mean low water. Mean high water values between 0.4 and 0.8meters were assigned to the shoreline. Fifteen points were foundthat were not consistent with the surrounding points.These were removed prior to tinning. DEM grid values outside theshoreline (on land) were assigned null values (-32676).Charlotte Harbor has eighteen 7.5 minute DEMs and four one degreeDEMs. 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.