DaveD Posted March 29, 2012 Share Posted March 29, 2012 I thought some of you might be interested in the on-going geodetic survey of the area around the Washington Monument -- Washington Monument podcast Quote Link to comment
tosborn Posted March 29, 2012 Share Posted March 29, 2012 Dave: What do you know about the history of the mini obelisk? It appears that it's PID is HV1841 and it was first recovered by NGS in 1971. The monumented date is unknown by the Department of Defense. Does this go back to the original construction of the Washington Monument? If it is more recent it seems like it would have been a lot easier to just drive a rod rather than create a 12 foot tall buried version obelisk. Enjoyed the podcast. Tim Osborn Quote Link to comment
DaveD Posted March 29, 2012 Author Share Posted March 29, 2012 The mini-Monument was the original bench mark established by Col. Casey of the Army Engineers who was the engineer in charge of the completion of the Monument. He set the mark to monitor settlement of the foundation during the construction. I know the datasheet says 1971 for the first time NGS visited the mark and I've tried for years to correct that. We actually first survey this mark in 1901 and on at least 13 different campaigns since then. Quote Link to comment
DaveD Posted March 29, 2012 Author Share Posted March 29, 2012 The mini-Monument was the original bench mark established by Col. Casey of the Army Engineers who was the engineer in charge of the completion of the Monument. He set the mark to monitor settlement of the foundation during the construction. I know the datasheet says 1971 for the first time NGS visited the mark and I've tried for years to correct that. We actually first survey this mark in 1901 and on at least 13 different campaigns since then. Quote Link to comment
foxtrot_xray Posted March 30, 2012 Share Posted March 30, 2012 Dave - Made the news again, this time, with your picture: http://wtop.com/?nid=109&sid=2807483 I've wanted to recover a few of those marks on the Monument, but... it's not worth it with all the park officers around. Quote Link to comment
+DukeOfURL01 Posted April 19, 2012 Share Posted April 19, 2012 I'm a little curious, what does the steel rod (key?) that is shown in the picture, do? Quote Link to comment
DaveD Posted April 22, 2012 Author Share Posted April 22, 2012 The "key" you saw in the picture is a special tool we use to remove the threaded cap which covers the actual bench mark which is embedded in the side of the monument. Then we slide a 18" stainless steel pin into the cavity and place the level rod on the pin. Once the measurements are completed we remove the pin and replace the cap so the cavity doesn't get filled with dirt and other debris. Only NGS and the National Park Service have access to these special tools. Quote Link to comment
+DukeOfURL01 Posted April 22, 2012 Share Posted April 22, 2012 The "key" you saw in the picture is a special tool we use to remove the threaded cap which covers the actual bench mark which is embedded in the side of the monument. Then we slide a 18" stainless steel pin into the cavity and place the level rod on the pin. Once the measurements are completed we remove the pin and replace the cap so the cavity doesn't get filled with dirt and other debris. Only NGS and the National Park Service have access to these special tools. Oh. What is being measured? Thanks. Quote Link to comment
+EdrickV Posted April 23, 2012 Share Posted April 23, 2012 The "key" you saw in the picture is a special tool we use to remove the threaded cap which covers the actual bench mark which is embedded in the side of the monument. Then we slide a 18" stainless steel pin into the cavity and place the level rod on the pin. Once the measurements are completed we remove the pin and replace the cap so the cavity doesn't get filled with dirt and other debris. Only NGS and the National Park Service have access to these special tools. Oh. What is being measured? Thanks. I'm going to make an educated guess that it was HV8077 in the photo, which would likely mean he was checking elevation. http://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=HV8077 Quote Link to comment
DaveD Posted April 23, 2012 Author Share Posted April 23, 2012 Exactly correct - HV8077 (B 8). Quote Link to comment
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