These data can be printed in a variety of ways to display various geologic features or used for digital analysis and modeling. Any hardcopies utilizing these data sets shall clearly indicate their source. If the user has modified the data in any way they are obligated to describe the types of modifications they have performed on the hardcopy map. User specifically agrees not to misrepresent these data sets, nor to imply that changes they made were approved by the US Geological Survey. Attribute accuracy was verified by manual comparision of the source with hard copy printouts, plots, and on-screen evaluation.
Line segments are a set of sequentially numbered coordiante 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 coordiante values. All nodes are represented by a single coordinate pair which indicates the beginning or end of a line segment. The horizontal position accuracy for the digital data is no better than 13 meters based on the digitizing RMS error.