+Colorado Papa Posted July 21, 2003 Share Posted July 21, 2003 Of all the benchmarks I've found, I have observed only two Witness Posts. What are they? Why and how are they used? Who installs them and when? What markers qualify for a post? How are they anchored? Quote Link to comment
+BlueDeuce Posted July 22, 2003 Share Posted July 22, 2003 Well, I don't know all the whys and wherefores, but in my short experience I have only seen witness posts when the marker is difficult to find, like in tall grass along a roadside. If there's a wooden utility poll nearby they may tack it there, otherwise they'll place a signpost. I have seen mentioned here that they may place the witness post at a distance to help prevent vandalism and you have to read the datasheet to know exactly which direction to look for the marker. Dustyjacket has a great website that may answer most of your questions. Here Quote Link to comment
Z15 Posted July 22, 2003 Share Posted July 22, 2003 What are they? They can be wood, metal or fiberglass or anything similar, seen pipes. Why and how are they used? To protect and aide in finding the mark. They are used as another reference (term witness is used in surveying) Who installs them and when? Usually the survey crews installs them either when they set the mark or later find it and use it. What markers qualify for a post? Any survey mark that you would want to protect but NGS witness posts are normally only on geodetic marks no matter the agency. How are they anchored? The old wood ones were set in concrete, and I have found metal ones set in concrete also but most all are just driven into the ground with a common fence post driver available at any home center or hardware store Quote Link to comment
+Dreamer of Pictures Posted August 4, 2003 Share Posted August 4, 2003 Recently on vacation I saw three fiberglass witness posts, apparently identical. The first was very close to a ground-level disk that I was specifically seeking. The second was in a minigolf course which is part of the ferry terminal at Lewes Delaware. The ground surface is covered in small pebbles; we scooped away the pebbles nearby (but not comprehensively), and could not find any benchmark. The third was in the wildlife refuge adjacent the Cape May (NJ) Lighthouse, on the blue trail along the beach dune, on the way to the Cape May Point Lighthouse Trek geocache. There were other metal posts nearby, and perhaps one of those was the actual benchmark. However, these second and third posts were not near (within 100 feet of) any benchmarks shown by the geocaching.com list. I wonder: is it possible that the witness posts were officially placed far from the corresponding benchmarks? The first one I saw was very near its corresponding benchmark. Dreamer of Pictures Quote Link to comment
+jeff35080 Posted August 4, 2003 Share Posted August 4, 2003 I have seen posts as far away as 150' from the actual mark. In fact, the text on the posts (signs) only states that the marker is nearby. Of course, most of the time the signs and posts are right next to the mark, but not always. Cheers! Jeff http://www.StarsFellOnAlabama.com http://www.NotAChance.com If you hide it, they will come.... Quote Link to comment
sixthings Posted August 4, 2003 Share Posted August 4, 2003 Hey Papa, check out JK0843 for photos of a mark with nearby witness post. the good thing about this mark is that it is in your area. check out the area and see how easy it is to find the mark when you know this witness post is there to help. Quote Link to comment
+Colorado Papa Posted August 5, 2003 Author Share Posted August 5, 2003 quote:Originally posted by sixthings:... check out the area and see how easy it is to find the mark when you know this witness post is there to help. Tell me about it! I almost screwed up JK1230 Glen Eyrie royally when I found reference mark 2 and without looking at it closely, logged it as a find. On a return trip from the opposite direction, came accross a Witness Post in the brush without a marker in sight. Upon reading the NGS Data Sheet, got more insight about the BM and returned to the site with a shovel. Uncovered the real thing and returned later to dig out RM-1. If it hadn't been for the Witness Post, I never would have discovered my goof 1950 Surveyor Quote Link to comment
sixthings Posted August 5, 2003 Share Posted August 5, 2003 funny you mention JK1230, Papa. i noticed the mistake, and was going to check out the area next week to see if the actual station was still around. i logged a find on JK1235 with the same error. of course, i first found the RM a long time ago, and photograhed it out of pure curiousity, without knowing any better. i returned to JK1235 just a few weeks ago, hoping to find the station, but it's gone, i fear. i'll update and correct that log right now. Quote Link to comment
+Colorado Papa Posted August 6, 2003 Author Share Posted August 6, 2003 Thanks to the Witness Post, have now recovered the station, two reference marks and the azimuth mark. The NGS data sheet was complete and right on the money! I never would have found the azimuth mark using only the geocaching.com detail page. 1950 Surveyor Quote Link to comment
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