(NOTE: The folowing is an excerpt from letter: sEN~137, dated 13 February 1952): from D. T. Robbins, Chief Engineer, Hal, to Manager, A.E. Co, Albuquerque, ~~ ow 1 oo ee ee ee ee "Greenhouse" coordinates ee ee mee we mw ee we we me me te eee N ft @ a Ivy" 2,307.86 EB 3,821.76 S465 20! ysis co 5,051.77 E “945 ..%3 147,390.40 E 83,523.60 Zero to Sta, 6A 6” le,1637595 E 86,391.46. a 6° dot 13" Star 6A Difference Stae Zero Location Ruby . 11,148.91 E "Greenhouse" coordinates 170%39-90 E 6,311.49847.06 E 125,304.64 3;7153.21 132,055.50 E 110,146,00 "Ivy" ms 58° 06! 5OmE Zero to Sta. 6A "Greenhouse" bearing | tLyytt 1 ott " tion Stas Zero e. W N 15,058.71 E “953 033 106,178.70 E 124,317.80 Zero to Sta. 6A u n 68 Difference 0 N 4H 11,947.10 B 3,426.89 103,067.64 E 262492 205 S 38° 2g' Seng 29' 338° 0° 00! 462- 58° To determine the location of any structure based on the "Ivy" coordinate system, coordinates of zero, S 0° oof 23" Difference apply the difference in bearings between grids at the particular location to the *Greenhouse® bearing. From the adjusted bearing and the given distance from zero to a structure compute the difference in coordinates to be applied to the "Ivy" mR NM.) 7- ee Sta. 6A Zero ' "Greenhouse" bearing a rye ne ee = "Ivy" Ty # ee Location Janet "Greenhouse" coordinates *“Iyvy" "Greenhouse" bearing . le The relation between local grids used for the "Greenhouse" computations and the new Atoll grid is as follows. This is based on the difference in bearings of the sero lines as computed from the two systems, and gives the relation of structure 6A to gero at each of the three locations, Pacific Southwest Region . Reproduced from the holdings of the National Archives Be ome ee EN “| eS —