Blick, G.H. 1991 Precisions of surveys in the Wellington region from networks designed for measuring crustal deformation 1969 - 1983. Lower Hutt: DSIR Geology & Geophysics. New Zealand Geological Survey report EDS 135 61 p.
Abstract: Part of the 1928-1930 Department of Lands and Survey, now the Department of Survey and Land Information (DOSLI), 1st order triangulation network in the Wellington region has been resurveyed, and extended, to monitor contemporary earth deformation. Nine horizontal direction surveys, and seven determinations of astronomical azimuth have been made between 1969 and 1983 of survey networks referred to as the Wellington Quadrilateral, Wellington Hutt Valley Geodetic Chain, Wellington Regional Monitoring Pattern, and the Wellington Polygon. Observations have been made by New Zealand Geological Survey, now incorporated within DSIR Geology & Geophysics, with some distance measurements by DOSLI and Works and Development Services Corporation (NZ) Ltd. The horizontal direction and astronomical azimuth observations were made using Wild T3 and Kern DKM3 theodolites, and the distance measurements using Geodimeter Model 8 and Model 6BL distance measuring equipment. Following reduction of the field measurements the precisions of the observations were estimated by a least squares variation of coordinates computation. The standard errors of the horizontal directions, computed using an assumed observational error of 3.5''/set, were used to weight the observations. A standard error of 5'' was used to weight the vertical angles, and 5mm + 2 pp, for Geodimeter Model 6BL and Geodimeter Model 8 measurements. Results of the least squares adjustments show these values to be reasonable estimates of the precision of the data. One vertical angle, two horizontal directions, and seven distance observations were considered outliers and were rejected from the adjustments. Scale differences of about 2 ppm were identified between day and night distance measurements made during a survey, day measurements being longer. The day and night measurements were combined, allowing for a scale error of the night observations, together with horizontal directions observed during a survey and were found to be consistent with each other allowing the data to be combined for joint adjustments. (auth)
