GeoWorms Posted October 22, 2003 Share Posted October 22, 2003 I've just started hunting benchmarks (partly because of a geocaching related case of poison oak that I dare not provoke further!). There are plenty listed in the area, but most appear to be destroyed. I have been going for ones at intersections (and many haven't been noted since 1970). Do road construction crews just destroy them without telling anyone? Quote Link to comment
+happycycler Posted October 22, 2003 Share Posted October 22, 2003 Yes 1 for 10 can be a good ratio. I have some streaks that where I had less finds per 10 searches. You can often increase your find ratio by looking for newer marks, those with ADJUSTED coordinates and of course those already found by another GeoCacher. But of course the older ones which have not been visited for a while can be more satisfying. Whatever way you go -- keep on searching them out! Everybody loves benchmarks more! Quote Link to comment
+GeckoGeek Posted October 22, 2003 Share Posted October 22, 2003 quote:Originally posted by GeoWorms:I have been going for ones at intersections (and many haven't been noted since 1970). Do road construction crews just destroy them without telling anyone? Where are they located? Some are in small manholes that are too dangerious to open. I've been having problems finding some that I think have been destroyed by installing ADA ramps. All I can say is check, double-check, tripple check. I find many time I read something wrong and that's why I can't find it. Also note that SCALED marks may be 300 - 600 feet off from where you're GPS says they should be. Quote Link to comment
BeachBum22 Posted October 22, 2003 Share Posted October 22, 2003 Do road construction crews just destroy them without telling anyone? I'm in an area where there's been a lot of development in the last ten years and lots of the markers I've looked for are MIA also. I've found some that are obviously destroyed, and whomever destroyed them didn't tell the NGS as they are still in the database with no comments. Always in areas with new construction - sidewalks replaced, culvert head wall gone, replaced by underground pipes, etc. But I always look two or three times before I give up on a marker and write it off as MIA. As someone else pointed out, the descriptions on the NGS datasheets can be confusing, so a fresh start sometimes results in finding one that was not found on a previous trip. BeachBum22 http://www.benchmarkhunting.com Just because I can't find it doesn't mean it's not really there. Quote Link to comment
GeoWorms Posted October 23, 2003 Author Share Posted October 23, 2003 Thanks for the responses. Most of the ones I've been looking for are supposed to be "in the asphalt" and "10 ft from the centerline of the road" but there's no covers or anything, just smooth blacktop. Another one was "3 feet from pole #418, near a witness post" and there was no witness post left. (I did find a witness post with no marker, but from reading I now realize it must be burried near the post)But I do want to look a little further before I declare them lost. Quote Link to comment
Z15 Posted October 23, 2003 Share Posted October 23, 2003 Just because you can't find then does not mean they are not still there, especially if you are new to this. I have dug up many that were buried over the years and I have dug and not found them. If they are in the pavement, best to move on to something easier to find. We found one that was over 1 ft deep and the only way we knew if could still be there was that we had the highways plans which gave us the roadway C/L elevation and we were able to determine the location and the ground was about 1 ft higher from landscaping the roadside. The NGS Data SheetSee file dsdata.txt for more information about the datasheet.DATABASE = Sybase ,PROGRAM = datasheet, VERSION = 6.89 1 National Geodetic Survey, Retrieval Date = OCTOBER 23, 2003 QL0371 *********************************************************************** QL0371 DESIGNATION - M 30 QL0371 PID - QL0371 QL0371 STATE/COUNTY- MI/MENOMINEE QL0371 USGS QUAD - NADEAU (1989) QL0371 QL0371 *CURRENT SURVEY CONTROL QL0371 ___________________________________________________________________ QL0371* NAD 83(1986)- 45 30 30. (N) 087 35 54. (W) SCALED QL0371* NAVD 88 - 221.132 (meters) 725.50 (feet) ADJUSTED QL0371 ___________________________________________________________________ QL0371 GEOID HEIGHT- -36.10 (meters) GEOID99 QL0371 DYNAMIC HT - 221.120 (meters) 725.46 (feet) COMP QL0371 MODELED GRAV- 980,558.8 (mgal) NAVD 88 QL0371 QL0371 VERT ORDER - FIRST CLASS II QL0371 QL0371.The horizontal coordinates were scaled from a topographic map and have QL0371.an estimated accuracy of +/- 6 seconds. QL0371 QL0371.The orthometric height was determined by differential leveling QL0371.and adjusted by the National Geodetic Survey in June 1991. QL0371 QL0371.The geoid height was determined by GEOID99. QL0371 QL0371.The dynamic height is computed by dividing the NAVD 88 QL0371.geopotential number by the normal gravity value computed on the QL0371.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 QL0371.degrees latitude (g = 980.6199 gals.). QL0371 QL0371.The modeled gravity was interpolated from observed gravity values. QL0371 QL0371; North East Units Estimated Accuracy QL0371;SPC MI N - 80,760. 7,953,240. MT (+/- 180 meters Scaled) QL0371 QL0371 SUPERSEDED SURVEY CONTROL QL0371 QL0371 NGVD 29 (??/??/92) 221.147 (m) 725.55 (f) ADJ UNCH 1 2 QL0371 QL0371.Superseded values are not recommended for survey control. QL0371.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums. QL0371.See file dsdata.txt to determine how the superseded data were derived. QL0371 QL0371_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TDR532395(NAD 83) QL0371_MARKER: DB = BENCH MARK DISK QL0371_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT QL0371_STAMPING: 725.546 M 30 1930 QL0371_STABILITY: C = MAY HOLD, BUT OF TYPE COMMONLY SUBJECT TO QL0371+STABILITY: SURFACE MOTION QL0371_SATELLITE: THE SITE LOCATION WAS REPORTED AS SUITABLE FOR QL0371+SATELLITE: SATELLITE OBSERVATIONS - September 20, 2001 QL0371 QL0371 HISTORY - Date Condition Report By QL0371 HISTORY - 1930 MONUMENTED CGS QL0371 HISTORY - 1934 GOOD NGS QL0371 HISTORY - 20010621 GOOD MIDT QL0371 HISTORY - 20010920 GOOD JCLS QL0371 QL0371 STATION DESCRIPTION QL0371 QL0371'DESCRIBED BY NATIONAL GEODETIC SURVEY 1934 QL0371'AT TALBOT. QL0371'AT TALBOT, MENOMINEE COUNTY, ON THE CHICAGO AND NORTH WESTERN QL0371'RAILWAY, 25 YARDS NORTH OF THE NORTH END OF THE BOXCAR STATION, QL0371'50 FEET NORTH OF THE CENTERLINE OF A ROAD, 35.8 FEET EAST OF QL0371'THE EAST RAIL, AND 1.7 FEET LOWER THAN THE TRACK. A STANDARD QL0371'DISK, STAMPED 725.546 M 30 1930 AND SET IN THE TOP OF A CONCRETE QL0371'POST FLUSH WITH THE GROUND. QL0371 QL0371 STATION RECOVERY (2001) QL0371 QL0371'RECOVERY NOTE BY MICHIGAN DEPARTMENT OF TRANSPORTATION 2001 (MPR) QL0371'AT TALBOT, ALONG US HWY 41, 1.11 MI N OF COUNTY RD 360, 0.175 MI S OF QL0371'COUNTY RD 366, AT ANDREWS LANE NO. 27. 81 FT WSW OF THE C/L OF US-41, QL0371'51 FT S OF A UTILITY POLE, 50 FT NNE OF THE LANE, 35.8 FT ESE OF THE QL0371'EASTERLY RAIL OF THE RAILROAD, 17 FT W OF THE WEST END OF A CULVERT QL0371'HEADWALL, 1.25 FT N OF WITNESS POST, 1 FT BELOW GROUND LEVEL. QL0371 QL0371 STATION RECOVERY (2001) QL0371 QL0371'RECOVERY NOTE BY JOHN CHANCE LAND SURVEYS INC 2001 (MRY) QL0371'RECOVERED AS DESCRIBED. *** retrieval complete. Elapsed Time = 00:00:01 Mike Survey Tech (Retired) Quote Link to comment
GeoWorms Posted October 23, 2003 Author Share Posted October 23, 2003 quote:Originally posted by elcamino:Just because you can't find then does not mean they are not still there...If they are in the pavement, best to move on to something easier to find So "in the pavement" means paved over, not just embedded flush? Quote Link to comment
AE5D Posted October 23, 2003 Share Posted October 23, 2003 For better results, search in your area (by zip code) for marks that someone else has already found. With a little more experience you will have better results, but there will still be times when you visit several benchmarks in a row without finding one. My longest dry spell was ten benchmarks in a row that I just couldn't find... all on the same day! That's an unrewarding way to spend a day off. Please be aware that there are many benchmarks out there in places that are just too dangerous to go. I've been to a few spots where I took more risks than I could ever justify for a picture of a benchmark. Quote Link to comment
Epyon_zuk Posted October 23, 2003 Share Posted October 23, 2003 I used to Co-Op on a state highway survey crew and we had to find benchmarks a lot. Sometimes they are buried under dirt, asphalt, dead chipmunks. I agree with AE5D, look for ones others have found so you can get a feel for it. Sometimes you just can't find them. GOod luck Brian D. Quote Link to comment
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