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Confused About Bridge Reconstruction


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Unless I'm completely lost, NB0907 (H 155) should be just down the road from my house. It's supposed to be on a bridge that was replaced a number of years ago. At the coordinates listed, there is a NYSDOT benchmark, not the original one. I was calling this a "not found", but I just downloaded the latest data sheet, and the thing is listed as recovered in 1995. If I'm not lost, then they either used the new mark, or the old one was reset close by. Can anybody clear up what normal practice is, and if this qualifies as found or not found? Be gentle- I'm a complete noob at this.

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Unfortunately is was recovered by the US Power Squadron (boating enthusiests) and may not be reliable, so I would not discount the fact they are wrong. They may have found what you found and not paid any attention to the facts.


I am hear to tell you I have found many errors in USPSQD reporting.

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If you look at the current datasheet, you can see that the recoveries in 1989, 1990, and 2005 were made by members of the USPSQD. USPSQD reports can be in error on occasion. If you are sure the bridge was replaced, along with the headwall, then it is likely that you are the one who is correct, and that the previous reports are in error.


NB0907 (H 155) is not found unless you see "H 155 1942" stamped on the disk. Whatever NYSDOT disk is currently at that location, it is not NB0907.


However, I will say that sometimes the superstructure of a bridge might be rebuilt on the old foundation, so you should be certain that you haven't overlooked the presence of the original marker. I found a somewhat similar situation recently at KV1342, where there was a NJ state marker on one side of a bridge, and the original NGS marker was hidden beneath a pipeline on the other side of the bridge.

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I was looking at this post and saw some remarks about the usps. LX4700 was recovered by wildbird and myself in early 2003 while there was about a foot and a half of snow on the ground. Later in the year the usps tried to recover the station and they couldn't even find Bald Hill Rd. which is right off of Rt. 190 in Union Ct. I wonder if they would have found the station if they had found the road.

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Recoveries by the Power Squadron are only as good as the individual. Some care, some don't. I have followed a USPS member in my area and found his recoveries to be quite good, on the whole (yeah, I have picked up a few "founds" where he had "not found" them, but not many!). Others haven't done so well. I take a USPS "not found" to be an invitation to find a mark, and I am usually correct in that assumption about 10-20 percent of the time.


I think the flaw is that the Power Squadron basically gives out merit badges or brownie points or something similar for benchmark reporting (I am being facetious here, but there IS some sort of credit received, and it is for any type of recovery, found, not found, destroyed, etc.). Since the credit is for just looking and reporting to NGS, sometimes the "looking" is a bit sloppy. Also bear in mind that the USPS folks are mostly interested in boating, not benchmark hunting. The benchmark hunting is part of the navigating lessons and credit.


I remember reading a page on site run by a local chapter of the USPS suggesting "making a day" of hunting benchmarks. The impression I got was to get it over with as quickly as possible. The suggestion of having a picnic, with wine!, let me know how serious that chapter was about the process.


I am not sticking up for the USPS here. In fact, I think their overall program is flawed, as it encourages the subsitution of quantity for quality. I am just trying to give a bit of insight into why I think they consistently turn in less than accurate results. But it isn't really the fault of the hunters--they only know what they are told, which is "go hunt 'em up and get credit."


A similar situation: I have seen just as many poor recoveries on GC.com from cachers who pick up a few casual benchmarks near caches. There are lots of pictures of reference marks posing as triangulation station disk in the gallery! Luckily they don't report to NGS so the damage is minimal.


Even the "official" agencies mess up from time to time. Take KW0765 for example. "Not found" by the USGS over 50 years ago, but there it is, undisturbed and in good condition.


Just thought of this... a question for the surveyors... what are the chances some junior surveyor is going to come along and use NB0907 for a survey point without doing the correct homework first? Is the false recovery an error of convenience, where some poor slob is sent out on a rainy day to set up over NB0907 and finds that it is the wrong disk (#%$!), or can it be worse, resulting in a sewer line that runs uphill?

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Thanks all- very interesting stuff as I come up to speed. Went out this morning on foot to find an easy mark just up the road. This is sort of an exercise program for me- as I exhaust the supply of marks close to home, I have to walk further!


I'll re-investigate the bridge from my original question to be sure the real disk is nowhere to be seen. I did log it as not found, but included a picture of the DOT disk- is that ok, or will it confuse somebody? I don't have the confidence to log anything as destroyed at this point. Thanks for the info on the power squad- I thought they were some official government or utility group, that was sure to be more successful at recovery them me. Did like the idea of benchmark hunting with wine, though.


There is another mark very close to here, where the landmarks are gone and the coordinates are highly questionable. I'm wondering if it might be buried near the road- do people have much success with metal detectors for finding these things?




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...Is the false recovery an error of convenience, where some poor slob is sent out on a rainy day to set up over NB0907 and finds that it is the wrong disk (#%$!), or can it be worse, resulting in a sewer line that runs uphill?

Surveyors typically know what they are looking for before they head out the door. If they set up over a mark that is close but isn't right they will figure it out. Since surveyors are usually the first on the project even if they set up on the wrong mark and have wrong coords for everything in the project. Those wrong coords will be assiend to real topo information and that's what the engineer will design from. His work will have incorect coods but will match up just fine to the real world. If the surveyor figures out the error at that point and corrects it but doesn't work with the engineer to update the design then they will figure it out when they go to connect and everthing is 3' off consistantly.

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Photobuff -


I don't think that there is any problem with reporting the existence of the no-PID NYSDOT mark you found on the datasheet for NB0907 as long as you clearly identify the other mark as NOT the mark described in the datasheet. I do that regularly (record no-PIDs on the datasheet of the closest PID station) to keep track of the extraneous odds and ends that I've found.


In the future, I think the new Waymarking site will probably have a category for US survey marks that are not in the Geocaching database. That will provide a standardized location and method for logging all the no-PIDs.


You are correct NOT to log the disk as DESTROYED. It's easy to determine that a water tank has been razed; it's much much harder to determine reliably that a disk (especially when the location is defined by scaled horizontal coordinates) has been destroyed. I think I have only a single destroyed disk to my credit (because, in part, I think that a NOT FOUND with good comments is just as good).


Metal detectors: I use a metal detector when I suspect that the disk I seek is either sub-surface or deep in a bunch of Poison Ivy (maybe, one in every twenty searches or so). I've had mixed results. Sometimes, it works like a charm. Other times (and, especially along road shoulders), there's so much metallic garbage mixed in with the fill that the detector becomes worthless.


The detector is generally no help unless either 1. the location of the disk I seek is defined by adjusted horizontal coordinates (and the handheld can get me to within 10 feet of the location), or, 2. the location of the disk is dfined by scaled coordinates and the description provides at least one precise measurement from a surviving environmental reference.


I would say that the metal detector has improved my "find rate" by about one or two percent, but it has shortened considerably the time I've spend searching for many marks that I would have found anyway. It is more of a time-saver than a disk-finder.

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To be honest, I never use the pics on GC as a resource, so whatever you post wouldn't confuse me. You described what you found so you are explaining and showing it. No problem there to me.


A metal detector can be very helpful, although the cheapie I have has only helped me find one mark so far in the 2 months I have carried it around. I wouldn't have found the disk without it though. I am sure that the more expensive ones will get you a hit deeper in the ground than mine. There have been some threads here about metal detectors and use.


Make sure to use all the tools at your disposal. You can see topographic maps directly from the benchmark listing on GC.com, if you click Topozone. Most benchmarks are listed on the maps as a small X with the elevation. Those Xs are what the benchmarks are scaled from. I have found that they are usually almost exactly where indicated, so if you link to Topozone from GC.com and your coords place you east of the X, you would be well off to head a bit west to start your search.


Another tool I use extensively is USAPhotoMaps. It is free if you don't mind an annoying pop up when you start it. I donated to help the creator--it is a great program and I am willing to bet all serious benchmarkers have at least tried it. You can load benchmarks into it (download them from the NGS and save them as GPX files. That can wait until you decide if you want to keep doing this though), then toggle between aerial photos and topo maps. I find the photos to be indispensible for seeing what is REALLY there.


For finding underground marks most of us use some sort or probe. There have been threads on that--some use a long screwdriver, I use a Walmart camp fork with the fork tines broken off. It gives me a wooden handle and a long pointy metal thing for probing for monuments a couple inches underground. It has been my most valuable piece of hardware so far.


Get a 100 foot tape measure too, a compass (even if your GPSr has one, a cheap compass is invaluable) maybe a small shovel for digging out marks from, and a brush to clean them off for pictures. That is about all I carry, in a back for easy transport.


By the way, I looked at some of the marks in your area on GC.com and to be honest, I suspect almost all of the 1989 and 1997 recoveries by the USPS. Although I don't know your area, the 800 series marks along the railroad have a pretty high chance of still existing, even though the tracks seem to be gone. Rarely is every single bit of a railroad removed. The bridges are usually left for quite some time, even those over roads, but most certainly those over creeks and streams. There is one mark described as being in a boulder and I wonder who would bother to remove a boulder that was beside the tracks? Hmmm. I think you have some interesting hunting ahead of you!

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Photobuff -


It is actually a very good thing to include a photo of the wrong-mark! So many times, people will log a find on a PID and it will be the wrong mark. Your not-found log accompanied by the wrong-mark picture should prevent anyone from erroneously logging a find with the NYSDOT mark.


I like your closup pictures of the disks. You should always take a 'distant' picture of each PID you find; a picture is worth a thousand words, I'm certain you know. ;) (I see you did include a 'distant' shot in one of your finds.) In the description of your 'distant' shot, its a good thing to include the direction you were facing when you took the picture. Many of use a photo editor program to include an arrow pointing out the disk if it's not 100 percent obvious in the picture.


Have fun benchmark hunting! ;)

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