Obtained county files in UNIX format from the EPA Region 7. Converted to singular precision coordinate, cleaned and reprojected to UTM zone 15. 5. Added acreage field. The classifications are from L.M. Cowardin, V. Carter, F. Golet, and E. LaRoe. 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 begining or end of a line segment. The neatline is generated by connecting the four corners of the digital file, as estabished during initialization of the digital file.