Powell River ISA Refresh 2022
January 17, 2022
On January 4th, 2022, the published values for all monuments in the Powell River ISA were subject to a 3-dimensional refresh. Changes were approximately 0.36m horizontal and -3.1m vertical; they were not uniform across the network. Some monuments were removed from circulation due to having an unknown compatibility with main ISA network. The new values are accurately referenced to official horizontal and vertical datums in BC. Surveyors can expect greatly improved compatibility with independent GNSS-derived positions via post-processing methods such as CSRS-PPP or baselines to provincial/federal active control. The corrections were derived from a GNSS sampling of the network; not all monuments were directly occupied and therefore the accuracy and reliability of corrected positions will have some limitations. That said, new network accuracy (with respect to official horizontal and vertical provincial datums) for the ISA as a whole, will be greatly improved over the previous published values.
Figure 1: The Powell River ISA as Shown in iMaps