Unlisted Benchmarks On Topo Maps

[Photobuff]

Along with the various search options for benchmarks in the database, I sometimes look at local topo maps to find benchmarks that might be interesting. I found one shown on the map at an intersection on the way to work- perfect. Usually I search for these by coordinates in the database and they pop right up. Not this one, but it might well still be there. Is there anyplace to else to find some clues as to what I might be looking for? This doesn't seem common; around here, almost every benchmark on the topos is listed in the database.

[mloser]

I am not a big hunter of undescribed benchmarks. In fact, I have found about 5 of them, all accidentally, which is pretty poor in comparison to others here, some of whom actively hunt them.

 

Chances are your X is a USGS mark and is part of the USGS database. The bad news--the USGS database is not online, nor does it seem it will ever be. You can request mark descriptions for your area from them--others here will provide you with information on how. Zhanna has taken the effort to get quite a few in her area of NE Pennsylvania and California.

 

As for guidelines if looking without a description. Look near telephone poles, on concrete bases and bridge abutments. Your mark may or may not be a disk. You could be searching for a chiseled square on the base of a traffic light, or a bolt or rivet. Disks are more prevelant near roads, the others along railroads, but anything goes.

 

There IS a NY geodetic control viewer, put up by the NY Transportation Federation, but it seems to be limited to only NGS marks. Take a look at NY Geodetic Control Viewer.

[Z15]

info from NGS (DaveD)

 

"The U.S. Geological Survey (USGS), an agency in the Dept. of the Interior has the responsibility for producing our national topographic maps. They completed the monumental task of complete national mapping of the 1:24,000 scale map series (about 55,000 maps) in the early 1990's. USGS would often set survey monuments to help "control" the map. Maps are produced from aeronautical photos mosaiced together. In order to provide accurate location, orientation, scale and elevation to a flat map of a curved surface, it is required to have numerous points that can be identified on the photographs for which the coordinates/elevations are well known. The marks set by USGS were a vital part of this operation. In the days when mapping surveys were conducted primarily by line-of-site methods, these marks helped save money by helping to ensure a network that cartographers could rely on for mapping update procedures. With the rapid developments in surveying and mapping technology, especially GPS, USGS sees little need to setting new marks or maintaining the old networks. Unfortunately the data for tens of thousands of these marks set by USGS were never submitted to NGS for inclusion in the National Spatial Reference System. Due to major reductions in staff and the changing nature of mapping requirements, it is highly unlikely that USGS will ever automate these data."

 

It should be noted that many (likely 98%) of the USGS marks appear in the database not becuase USGS submitted them but rather USCGS and NGS found them and used them in their surveys. Yes there are exceptions to this but I am talking in general.

Edited December 19, 2005 by Z15

[+Crystal Sound]

I've searched for quite a few of those "non-PID" marks found on topo maps, and had pretty decent success at finding them.

 

Especially, when compared to looking for PID marks, from GPS coordinates, and without a datasheet.

 

In my area, most seem to be located on bridge abutments, and a careful inspection of which side of the road, ect the "X" lies upon, leaves a good clue as to where the mark may be located. "A picture is worth a thousand words."

 

If it's still there, it's pretty much been a case of "walk right up to it".

 

I find it to be a pretty fun challenge, though there's little practical point to it, since there really isnt anyone to report the find to. Which is why I mostly hunt for PID marks, and report my findings to the NGS.

 

Most of the non-PID marks I find, are during my outings working on my NMC quad, or while i'm out caching and referencing Topo maps.

[Photobuff]

Thanks for the replies. My main interest is in PID marks that nobody else has been able to find. Anything that's been visited in the last decade or so has much less mystery to it, at least for me. I just stumbled across this unlisted one, and figure it's one more thing to have a look for when the weather warms up. That NYS marker map is neat. It doesn't have any new information, but it beats my entering everything into USAphotomaps by hand!

 

No, I don't work at Harbor Freight, but just have to mention they have really nice long tapes for very little. I just picked up a 165' tape for $12.99 and I think I saw some at over 300' for not a lot more. Should help with some of those descriptions where the landmarks are a ways away.

[mloser]

You don't need to enter everything in USAPhotomaps by hand!

 

Go to the NGS site and download the PIDs you want. I have been doing it by county in order to keep each file managable, but you can download by USGS quad, radial, and rectangular searches.

 

Save the resulting screen as a text file (.TXT). Make sure to wait until it is completely loaded first. Then clean up the top and bottom of the text to remove all non-datasheet text, and run it through BMGPX (Get BMGPX from Parkrrr/BMGPX. Voila, a GPX file that you can read directly into USAPhotomaps, as well as the latest version of MapSource, if you are a Garmin person.

 

A 165 foot tape would be great. There have been quite a few times when I had to measure over 100 feet and that can be a pain. I am not so sure I want to drag a 300 footer around though!

 

Edit: Wait! Their tapes are in METRIC too! Now THAT is a big deal, because the box score on triangulation stations is only in metric, so I can skip doing the conversions. I will be stopping by Harbor Freight this week. Early Christmas for ME! Whoo hoo.

 

Matt

Edited December 19, 2005 by mloser

[+Black Dog Trackers]

Photobuff, mloser, Crystal Sound -

 

For those non-NGS marks you can log them at the Recovered US Benchmarks Waymarking site. So far, 26 people have entered 127 waymarks there. As seventhings points out, it's an interesting challenge to craft the entire location description when you have none to start with.

 

One challenge of logging these is to pick a topo quad you're working/interested/living in and log all the BMs on it that are not in the NGS database, if you can find them (or even if you can't).

 

As far as mapping this activity to real-world usefulness, although the USGS doesn't seem particularly interested in recovery reports, if the collection of non-NGS waymarks is good enough, local surveyors could someday use it to locate a mark to use in their project as Z15 pointed out above:

It should be noted that many (likely 98%) of the USGS marks appear in the database not becuase USGS submitted them but rather USCGS and NGS found them and used them in their surveys.

 

I'm using a local county database to find some non-NGS marks right near where I live whereas all the NGS ones have already been logged, so it's a new resource of benchmarks to have fun finding.

 

The main thing though, is that if you find a benchmark that's unlisted while you're finding an NGS benchmark or geocache, you can waymark it just for fun.