UNITED STATES DEPARTMENT OF COMMERCE
                                   National Oceanic and Atmospheric Administration
                                   NATIONAL OCEAN SERVICE
                                   National Geodetic Survey
                                   Silver Spring, Maryland 20910-3202

                                   October 27, 1995




MEMORANDUM FOR:  Distribution       

FROM:            Captain Lewis A. Lapine, NOAA
                 Director, National Geodetic Survey

SUBJECT:         Federal Base Network (FBN) Replacement Policy


The following policy for FBN replacement surveys was developed in
accordance with Strategic Goal #3, Development of the FBN, and
approved by the NGS Executive Steering Committee on August 2,
1995.

POLICY: In general, destroyed FBN-stations shall be replaced in
a timely manner, and the survey to reestablish them shall be
designed to achieve their original accuracy.

   ‚ Destroyed FBN stations shall be replaced within 12 months
     of the station being found destroyed.

   ‚ The replacement survey for A-order stations will follow
     A-order specifications. Similarly, the replacement survey
     for Border stations will follow B-order, or better,
     specifications.

   ‚ An NGS field party will generally be required to perform
     the A-order surveys, however, they may be assisted by state
     personnel. The B-order replacement surveys may either be
     performed by an NGS party, or an NGS State Advisor will
     provide technical guidance to a cooperating agency.

   ‚ Replacement surveys for Cooperative Base Network (CBN)
     stations will be done by cooperating agencies, preferably
     under the technical guidance of a State Advisor, and follow
     B-order specifications.

   ‚ If the destroyed monument was also a bench mark, an effort
     will be made to find a nearby existing bench mark to serve
     as the replacement. Otherwise, the replacement survey will
     include leveling observations.


Distribution:
N/NGS  - Challstrom           N/NGS   - Leigh
N/NGS  - Fisher               N/NGSl  - Mitchell
N/NGS  - Lucas                N/NGS2  - McKay
N/NGS  - Spencer              N/NGS3  - Floyd
N/NGS  - Strange              N/NGS4  - Wade
N/NGS  - Weston               N/NGS5  - Schwarz