Three datasets are included: the official state boundary line, the county boundary lines, and the land/shore outline. These geospatial data files comprise the bounding lines relating to the political boundary delineation for the State of Delaware as well as the shoreline taken from the 2002 orthophotos of Delaware.
No formal horizontal positional accuracy testing has been performed to qualify or validate these data. The horizontal positional accuracy of the source data used to generate this boundary varies greatly. Accordingly, the placement of boundary lines on land are generally more horizontally accurate and reliable than the position of boundary lines as they exists on large water bodies such as the Delaware Bay and the Atlantic Ocean. These boundary lines are positoned so they are coincident with known boundary monuments and boundary points. Boundary monument positions were based upon NGS coordinates as documented in several joint agreements between the States of Delaware, New Jersey, Maryland and Pennsylvania. These monument positions were stated to be within first and second order horizontal network accuracy. Not used were the computed boundary points and boundary reference monument positions from "Exhibit C" of the Joint Agreement between Delaware and New Jersey along the 1934 mean low water line (20010829). Boundary, boundary monument, and boundary reference monument positions were calculated and included in this file along the mean low water line of the Delaware - New Jersey boundary. These values were calculated from descriptions in the 1934/1935 U.S. Supreme Court Decree.
Please give proper credit to the Delaware Geological Survey.
These datasets were produced to serve as a representation of the Delaware State boundary and land outline in support of the Delaware's Spatial Data Framework/DataMIL project.
Official State Boundary
Mr. William Schenck of the Delaware Geological Survey graciously provided most of the sources that were used either directly or indirecly to create this version of the lines comprising the Delaware State boundary. A text file containing NAD83 (1991) point positions for boundary and reference monuments was created. This information was extracted from Joint Agreements between the States of Delaware, New Jersey, Pennsylvania, and Maryland. Not used were computed boundary points and boundary reference monument positions from "Exhibit C" of the Joint Agreement between Delaware and New Jersey along the 1934 mean low water line (20010829). Added to this text file were 1) additional calculated positions along the Delaware - New Jersey boundary originating from the 1934/1935 U.S. Supreme Court Decree, and 2) other pertinent miscellaneous point positions used in the computation and delineation of the boundary. The mean low water line portion of the boundary between the States of Delaware and New Jersey was revised by locally registering the composite map from the 1934/1935 U.S. Supreme Court Decree with the USGS boundary DLG data and the 2002 orthoimage. The geometry of this revised boundary was then registered to the calculated positions of appropriate monuments as described in the 1934/1935 U.S. Supreme Court Decree. A series of GIS computer software (ESRI Arc Macro Language) - AML) programs were developed by Mr. George Miller of the USGS that used as input, the positional data from the source information listed above. Output from this program yielded an an ESRI coverage. The ESRI coverage data were then exported to point, line, and polygon shapefiles. The line shapefile was then interactively edited in order to fulfill specific content and attribution requirements.
The Delaware State Outline GIS dataset comprises the bounding lines relating to the official political boundary delineation for the State of Dela