Shoreline Change Map Data for Tidewater Maryland

      These are vector format maps. Unlike raster images, they can be rescaled without distortion.  The maps were created in ArcGIS 8.3 and consist of polyline segments and polygons.  The dates of these shorelines range from the mid 1800's to the 1990's.  Three file formats are available:  Autodesk's Drawing Exchange Format (.DXF), ESRI's Shapefile (.SHP) and Arc Export (.E00) formats.  These are widely accepted vector data standards and are used by programs such as AutoCAD, ArcGIS, ArcInfo, CorelDraw, Adobe Illustrator, JASC's Paint Shop Pro, Bryce 3D, 3D Studio Max, and many Intergraph programs.  The ESRI .SHP file format contains shoreline attribute data. 
     A complete metadata file accompanies each file.  You may also download the complete metadata in a zipped filed here. The metadata describe map projections, attributes, compilation procedures and all other critical parameters necessary to the proper use of the data. 
     The maps are available in two groupings, found in the charts below:

• Shoreline Change Maps by Quadrangle . Each zipped file contains the most recent shoreline and one or more historic shorelines.
• Shoreline Change Maps by County. Each zipped file contains a base shoreline and one or more historic shorelines.

      To download data click on the desired file format in the table below. Files have been compressed with Winzip to decrease download times.  You will not be able to view the files on-line.
     We also have Shoreline Change Maps in PDF format available for download.

The image below is an example of shoreline change map data displayed in ESRI's ArcMap GIS software

Anne Arundel

      For the coastal regions of Maryland, the Maryland Geological Survey (MGS) has periodically compiled maps depicting shoreline position at several points in time. The most recent compilation -- the first electronic one -- involved (1) digitizing historical (1841-1977) shoreline maps, all derived directly or indirectly from National Oceanic and Atmospheric Administration coastal survey maps (topographic or T-sheets), and (2) interpreting recent (1988-1995) shorelines from digital orthophotography. MGS is using the shorelines to update a series of Shoreline Changes maps and to determine coastal land loss, by watershed and by county, during the last half of the 20th century.
     This data set contains past shorelines, dating from 1841 to 1995, for 125 7.5-minute quadrangles covering the coastal regions of Maryland (see below). Originally in MicroImage's TNTmips .rvc format, the shoreline vectors have been converted to Arc/Info "Export" (.e00) format. They are registered to the Maryland State Plane Coordinate System (North American Datum of 83, meters).

Spatial Reference Information:

• Map Projection Name: Lambert Conformal Conic
• Grid Coordinate System Name: State Plane Coordinate System 1983
• SPCS Zone Identifier: 1900 (Maryland)
• Planar Distance Units: meters
• Horizontal Datum Name: North American Datum of 1983
• Ellipsoid Name: Geodetic Reference System 80
• Semi-major Axis: 6,378,137 meters
• Denominator of Flattening Ratio: 298.257
• Depth Datum Name: The aerial photography from which the DOQQs were developed was not tide-coordinated.  Therefore, shorelines in this data set does not represent a consistent vertical datum.

Shoreline Attributes:

• beach
• vegetated
• structure
• water’s edge

     All four categories are linear features, except “beach,” which, if sufficiently wide, can be both linear and polygonal.  Shorelines were merged into 7.5-minute quadrangles, provided that the aerial photography on which the DOQQs were based was flown in the same year. 
     Please see the complete metadata online or attached to each downloaded data file.