Monday, September 28, 2009

When Is a Boundary Really a Boundary?

Controversy is brewing between Highland County, Virginia and Pocahontas County, West Virginia over their common boundary. The planned Highland County Wind Farm has sparked debates over nearby historic resources and environmental impact. In addition, an issue of interest to geographers is the location of the shared boundary. Where is the “official” state boundary between West Virginia and Virginia? Turns out this is not such an easy question to answer and highlights some of the difficulties Virginia will face when tasked with improving the accuracy of geospatial boundary data.

The West Virginia perspective – state boundary.
West Virginia, uniquely among the 50 states, has declared in Code that its state boundary is that which is represented on the US Geological Survey quadrangle maps (See Section 2.2.3 of USGS Quad Specs and West Virginia Code ).

The Virginia Perspective – state boundary.
References to the Virginia boundary with West Virginia in the Code of Virginia are generally absent, other than a reference to the WV – VA boundary between Loudoun County, VA and Jefferson County, WV. Details are provided for the boundaries with North Carolina, Tennessee, Kentucky, Maryland, and the District of Columbia.

Where does this leave the Virginia definition of the state boundary for the Virginia border with West Virginia? Thanks to Mike Zmuda, State Surveyor at VDOT, I can point to the following historical information. It seems to boil down to the County Boundary definition at the time of the formation of the state of West Virginia. More specific information about the Virginia counties that became part of West Virginia can be found at the Proceedings of the Second Session of the Second Wheeling Convention, August 20, 1861.

So where is the county boundary between Highland County, Virginia and Pocahontas County, WV? The following was excerpted from a letter that the surveyor Jeffrey Hiner, who was hired by the Highland New Wind Development company, wrote to describe his survey work in support of the project:

Highland County was formed in 1847 from Bath and Pendleton Counties. The survey of Highland County is recorded in Surveyors Record Book 1 page 1 in the Courthouse at Monterey…. The northwestern corner of Highland County is described as “eight hemlocks and three small beeches and a small maple on the top of Alleghany Mountain in the Pocahontas County Line.” The line then runs southward “along the main top of said mountain with said county line to the plum orchard,” where the surveyors “marked one plum tree on the top of said mountain.” …
…An excerpt of the 1821 Acts of the General Assembly obtained from the book History of Pocahontas County West Virginia states the Pocahontas County Line ran “a straight line to the top of the Allegheny Mountain opposite the head of the east fork of Greenbrier River; thence with the top of said mountain to the Pendleton line, and thence with the top of said mountain to the beginning.”

The ridgeline of Allegheny Mountain is apparently a factor of the boundary definition. From a GIS data perspective, a couple of things come to mind when defining the ridgeline:
  • If USGS quads are used to define the ridgeline, the National Map Accuracy Standards for USGS quads should be considered. A horizontal distance of plus or minus 40 feet for “well defined points” is the NMAS value for 1:24,000 scale USGS quads. Positional errors for features can be greater than 40 feet when located away from “well defined points”.
  • How should the West Virginia reference to USGS topographic quadrangle maps be used for more precise boundary delineations? Is the authoritative source the cartographic representation, or the terrain feature (the ridgeline) which it appears to represent?
  • Elevation data such as Lidar and/or Digital Terrain Models could prove very useful if available.
Of course, Virginia law states that the determination of property lines and boundaries for legal purposes are the domain of Licensed Land Surveyors; otherwise, they are to be used for general information (§ 54.1-404 or 54.1-406 ).

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