Sharing new data layers developed directly from these data would also be appreciated by NWRC staff. Users should be aware of that comparisons with other data sets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in photo interpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such. Persons intending to engage in activities involving modifications within or adjacent to wetland areas should seek the advice of appropriate Federal, State, or local agencies concerning specified agency regulatory programs and proprietary jurisdictions that may affect such activities. Polygons intersecting the neatline are closed along the border.
Line segments are a set of sequentially numbered coordinate pairs.
No duplicate features exist nor duplicate points in a data string. Intersecting lines are separated into individual line segments at the point of intersection. Point data are represented by two sets of coordinate pairs, each with the same coordinate values. All nodes are represented by a single coordinate pair which indicates the beginning or end of a line segment. The neatline is generated by connecting the four corners of the digital file, as established during intialization of the digital file.