Anomaly Selection for Deflection Interpolation Part 2. Practical Application
HAWAII UNIV HONOLULU INST OF GEOPHYSICS
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The Test Phase utilized three astro-geodetic deflection stations in the Rocky Mountain area of the western United States. These were deflection stations 102, 105, and 116 from USCGS Special Publication No. 229. Using the adopted procedure, the Xi deflection component was interpolated between stations 105 and 116 to obtain an interpolated Xi value at station 102. A comparison of this interpolated Xi value with the astro-geodetic Xi value showed that the two differed by only .22 in. Since the accuracy of the astrogeodetic values probably do not exceed .2 in., the results were considered highly satisfactory. The Application Phase pursued deflection interpolation in an area in the Alps chosen by ACIC. In this case three deflection stations were chosen from a deflection of the vertical map provided by ACIC. These were designated stations 1, 2, and 3 for convenience. Using the adopted procedure, the eta deflection component was interpolated between stations 1 and 3 to obtain a value at station 2. As there were no individual deflection values given, the astro-geodetic deflections were estimated from a eta deflection component contour map with a 2.50 in. contour interval. Because of the manner of obtaining the astro-geodetic deflections, they are considered to have an accuracy of the order of .5 in.