In calculating the datum shift from the NGVD 29 to NAVD 88, I notice that Mount Curwood is closer in height to Mount Arvon using the new data. Mount Curwood at 1,978 feet had long been considered the Michigan highpoint until surveyors in 1979 found Mount Arvon at 1,979 was a foot taller. However in 1988 the USGS said its height calculations were wrong because the measuring instruments had not taken into account the impact of gravity and mass. In the majority of the cases the mountains still maintain the same relative height ranking. However for mountains that are close in height there could be a flip flopping of the rankings. So running the two mountains through the NOAA Vertcon cacluator we find that Mount Curwood 0.06 metres or 2.362205 inches taller while Mount Arvon is 0.049 metres or 1.929134 inches taller. This means Curwood has a net gain of 0.433071 inch on Arvon. That’s still not enougth for Curwood to gain the foot difference between the mountains to begin with. The USGS tables are rounded off to feet. Conceivably this could place both mountains in a “statistical rounded” tie (although all this comes into play only if the difference between the mountains in less than half an inch). Does anybody have the exact heights of the mountains?
Posted in Highpoint (States) News, Michigan by roger with .