Life Cycle of Control Point Positions: A Case Study Using a Multi-State Control Point Database (MCPD)

摘要

The life-cycle (usability) of a control point's position is tied closely to the control point's stability, its datum, and velocity changes across a region due to crustal movement. Analyses of the coordinates of numerous control points stored in the Idaho and Montana Multi-State Control Point Database (MCPD) showed no statistical differences due to a point's stability and its physical setting. However, analyses comparing various realizations of horizontal datum revealed some significant differences. Specifically, there is & 1 m difference observed between coordinates using NAD 83(1986) relative to NAD 83(2011) and approximately 2 cm difference between NAD 83(CORS96) and NAD 83(2011) coordinates. A comparison of vertical coordinates derived from geoid models revealed a 30 cm mean difference between GEOID03 and GEOID12A, and & 60 cm difference between GEOID99 and GEOID12A. The impact of velocity on these coordinates was apparent and varies strongly with local tectonics across the eastern Idaho study area. This study supports the NGS recommendation to use the most current realization of horizontal and vertical datum available.