This edition of the Glossary of Mapping, Charting, and Geodetic Terms was prepared under the direction of the Defense Mapping Agency. The purpose of this glossary is to provide a comprehensive and an authoritative source of current usage of mapping, charting, and geodetic terms for all levels of users to help them communicate effectively. The terms and definitions in this publication were selected from authoritative glossaries and dictionaries, and from technical publications and papers concerned with the many disciplines associated with mapping, charting, and geodesy. Numerous changes, additions, and deletions were made after a thorough review of the Third Edition by Defense Mapping Agency components and by the Departments of the Army, the Navy, and the Air Force.