These are vector format files. Unlike raster images they can be rescaled without distortion. The files on this page were created in ArcGIS 8.3 and consist mainly of polyline segments of the shorelines that are shown on the PDF maps. 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. 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. Place your mouse over the index map below to find a quadrangle name. You can find the quadrangle name and data in the table below. 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). 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. Maryland Geological SurveyRichard A. Ortt, Jr., Director2300 St. Paul Street, Baltimore, MD 21218 (410) 554-5500 Source.