Document Type

Data

Department/Program

Virginia Institute of Marine Science

Publication Date

12-23-2014

Abstract

Abstract: The 2013 Chesapeake Bay SAV Coverage was mapped from 1:24,000 black and white aerial photography to assess water quality in the Bay. Each area of SAV was interpreted from the rectified photography and classified into one of four density classes by the percentage of cover. The SAV beds were entered into an SDE GIS fetaure class using the quality control procedures documented below. The dataset contains all SAV areas that were identified from the areas flown. Some areas that are presumed to contain no SAV were not flown. Some small beds, particularly along narrow tributaries may not have been distinguishable on the aerial photography. Purpose: The annual SAV aerial photographic monitoring program provides a comprehensive and accurate measure of change in SAV relative abundance that has been used to link improving water quality to increases in bay living resources. Dataset credit: SAV Ecology, Monitoring, & Restoration Program, Virginia Institute of Marine Science Attributes FID SHAPE QUADID BEDID DENSITY BEDLABEL ZONE_ CBPSEG ST SHAPE_Area SHAPE_len Surveyed

Description

Coordinate System Details Map projection Map projection name: NAD 1983 UTM Zone 18N Scale factor at central meridian: 0.9996 Longitude of central meridian: -75.0 Latitude of projection origin: 0.0 False easting: 500000.0 False northing: 0.0 Planar Coordinate Information Planar coordinate encoding method: coordinate pair Coordinate representation: Abscissa resolution: 0.000000002220024164500956 Ordinate resolution: 0.000000002220024164500956 Planar distance units: meter Geodetic model Horizontal datum name: D North American 1983 Ellipsoid name: GRS 1980 Semi-major axis: 6378137.0 Denominator of flattening ratio: 298.257222101

Keywords

SAV, vegetative surface cover, submerged aquatic vegetation

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