Howdy Timenuts- It has been a few years since I went to school on these, and there have been some changes. Basically, to find out the specifics on the benchmarks, you can go to the USGS website, and search for the benchmark, from the info on the brass plate. You can find the 'Order' of the benchmark, which will tell you its accuracy. In my time, there were 1st, 2nd, and 3rd order benchmarks, but they have since re-surveyed some of the benchmarks, now designated as 'High Accuracy'. Good luck. -
Dave Powers ________________________________ From: Michael Baker <[email protected]> To: [email protected] Sent: Wed, September 14, 2011 7:39:44 AM Subject: [time-nuts] USGS Benchmark accuracy...? Hello, Timenutters-- There is a USGS survey benchmark on the side of the road just a half-mile from my house. Any guess as to how accurate these are? I parked my pickup truck over the benchmark with the LH box and antenna ( a 10 year-old Trimble surveyors antenna). I only let LH run for an hour-- I am not sure how I could leave a LH box out there for a long survey period without running the risk of theft. The survey marker is about 20 feet off the side of the road in a grassy area and marked only by a 4-foot-tall plastic USGS geodetic pole next to the buried concrete post. The head of the marker post with the brass plate on the top is flush with the surface, but covered with grass. I had to scratch around to find it. There is also a second concrete post in the ground about 30-40 feet away-- apparently you line up the two concrete markers to give you a true cardinal direction. Mike Baker -------------------------- _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
