This is a Vector data set. The map projection used is Lambert Conformal Conic. The horizontal datum used is NAD27. The semi-major axis of the ellipsoid used is 6378206.4 meters. This is an alphanumeric combination of degrees north and west with a row column index applied to each 1 degree by 1 degree area.
Values are in decimal degrees.
Q15 - Indicates if arc is also a boundary for a 15 minute quad. 0 - arc is not a 15 min. 0 - arc is not a 7.5 min. Each quad is annotated with the quad name. This data set was created to serve as base map information.