NA UMA ALLA LE. REPOSITORY ZAC/EIC SourHMésT KECION COLLECTION AG 326 ATOMIC ENERGY Commission HORIZONTAL CONTROL BOX No. £79674 #081) Aud24 _326-6546/70 FOLDER VAS1- 1952 beRZone TAL CONTE SURVEY (95S EXPANSION ENIMETOK ATOLL MARCH Is# STIS NOw Reproduced from the -holdings of the National Archives Pacific Southwest Region The horizontal control scheme has been expanded until it now includes the entire Atoll. It consists of a primary network of second order triangulation supplemented with third order stations at locations of lesser importance. The few remaining islands which have not been included in the scheme can be located by single triangles from exist ing controls. PREVIOUS SURVEYS BEST COPY AVAILABLE Some features of previous surveys were utilized in establishing the scheme. The earliest survey from which records are available was completed in 19) by the 0.5.8. BOWDITCH to control the hydrographic mapping of the Atoll. As this survey was of third order accuracy and most of the stations were not on project islands it was not adaptable to requirements of this project. However, the geographic position of station North Base on Runit Island and the azimuth of the line North Base-Sand became the origin of position and agimuth for the later surveys. A survey was completed in 197-8 by the JOINT TASK FORCE SEVEN consisting of a limited scheme covering the eastern portion of the Atoll. The scheme was stated to be of first order accuracy but it was only because of its limited extent that it could be considered of such nigh order. As the south end of the original base line had been destroyed a new base line, North Base-Runit, was established and the azimuth of the line was line North Base-Sand. computed from its relation to the Expansion of this scheme involved re-occu- pation of all of its existing atations and it became obvious -l- that