BMs: Are They Actually Used Much Anymore?

[+pgrig]

I started thinking (always a dangerous thing) about why some of the marks I find have been re-set, while others are left in forlorn disrepair. Then there was Wintertime's comment about my PR pitch to homeowners on the value of state and federal marks as a check on local surveys.

 

So my question is, as a practical, everyday matter, do these marks get much use anymore? Do public or private engineers "occupy" stations set in the 1840s (or for that matter, the 1930s or the 1980s) for any contemporary reason? I suppose the answer to this differs depending on the pace of public improvements or private development in one's neck of the woods, so my question is aimed primarily at sleepy, well-developed New England.

 

In my limited experience, searching only in MA, I don't find many (any?) marks set much after 1980, the average date of monumentation seems to be about 1952, and the distribution seems to be heavily bi-modal, with big peaks around 1935 (WPA) and 1970 (suburban development and road-building?).

 

I'm also curious about why some damaged stations are re-set while others are left to languish, turning their empty drill holes to the cold New England winds.

 

Has anyone had any budget for maintaining these stations since about 1985?

 

-Paul

[AZcachemeister]

Yes, they are still being used.

I can't tell you how many times I have made a recovery, and found recent evidence of the mark being occupied.

More than a few times, I have seen survey GPS set-ups on marks I have previously recovered.

Once, I actually recovered a mark while the site was occupied, and another time I arrived just minutes behind the surveyor. I asked if the mark was good, and he said, 'Yes, do you need to use it?'.

 

I can't speak to your question about the ones that aren't being 'maintained', but I think you answered your own question when you mentioned 'budget'.

[Bill93]

The vertical control true bench marks are still important. There is much work that needs them. As an example, our city is recovering from the biggest flood in its history and there was an article in the newspaper with a picture of the bench mark that they are referencing FEMA elevation certificates to.

 

There was an item on the NGS home page a while back about a proposed plan to gather more gravity data so that in maybe 10 years it will be easier to get geodetic elevations from GPS elevations. If successful, that will greatly decrease the importance of the average bench mark but they will still need high quality ones, probably within each county, for monitoring.

 

This change in importance has already happened to horizontal control marks. They aren't interested in intersection stations, and relatively few triangulation stations get occupied. GPS may be referenced to a few high quality (HARN, CORS, or similar) horizontal points and used to quickly determine other points with several miles by GPS.

[2oldfarts (the rockhounders)]

When we found F51106 ZONA, a 1898 Drill Hole in rock, it definitely had been used by a surveyor.

 

And FS1107 T 140 another drill hole with a metal rod placed right over it with guy wires. And this one is way back in the boonies. A 4X4 is nice to have for this one with a hike uphill.

 

It is great to know that some of these oldies are still being used today.

 

Plus, we have recovered several that have had the Surveyors equipment occupying the station.

 

HO0112 A 57 that had the Tripod there for at least 2 months.

 

And just south on Highway 89 from Page, GP0283 L 404 and here are a couple of those picks that I just remembered that I had gotten and never updated the mark till now....

 

So, when anyone wants to use a mark, they are just there waiting and the next person doesn't need to use the time and effort and expense of having to set another mark for their work.

 

That is really where we "Hobbyist's" at this site come in handy, pictures and logs of what we find. Several Surveyors have let us know here on our forum, that they check Geocaching.com to see if a mark has been logged. It just makes their life a little easier and ours a whole lot more fun.

 

Shirley~

Edited August 30, 2008 by 2oldfarts (the rockhounders)

[+PFF]

Here in North Carolina, I sometimes drive past stations occupied by surveyors, and it is very common to find survey tape which varies from fresh and bright, to faded by the Sun. I also see horizontal marks referenced in recorded plats across the state. In fact, there is verbiage on subdivision plats that there was (or was not) a NCGS station within x,xxx feet. It appears that a surveyor is required to "tie" to a marker, if it is available within a certain distance. [is there a confirmation from the Pro's on this?]

 

I know of at least 80 benchmarks which were monumented in the past 12 months, and there are many more if you go back 36 months. I have recovered 25 marks 6 to 12 months old in Johnston County, alone. I've also noticed numerous new marks showing up around Chapel Hill, Burlington, Wilmington, and over in the mountains. So, there must be some current value to benchmarks, when you consider the expense of setting new ones.

 

And North Carolina is not alone. On one of my trips to South Carolina, I was killing time waiting for the SCGS Boundary Specialist (Alan Jon Zupon) to meet me. While logging an old station, I noticed a new one about 300 feet away, on the shoulder of US-1. The cement was barely dry. I pointed it out to AJZ when he arrived. He commented that his state has an aggressive program of setting benchmarks at several-mile intervals along major highways.

[+Harry Dolphin]

 

Yup. Think this one was used recently.

[Papa-Bear-NYC]

Pine Hill Reset

 

Set in 1835 as a 4" x 4" brown stone monument.

 

Reset in 1932 as a disk

 

Resurveyed in 2008 (while we were visiting) as a GPS station.

 

That's 173 years and still going strong!

 

Edited September 2, 2008 by Papa-Bear-NYC

[ArtMan]

In my limited experience, searching only in MA, I don't find many (any?) marks set much after 1980. ....

Also, don't forget that the Geocaching.com database was frozen in time ca. 2001, so marks set since then won't be included, though of course they will be in the NGS database.

 

Many other marks set in recent years won't appear in the NGS database for various reasons but are used by state, county, or municipal agencies, or other special purpose entities, such as water districts, transit agencies, and even theme parks.

 

-ArtMan-

[+Black Dog Trackers]

pgrig -

 

My answers to your 3 questions:

 

1. As others have said, NGS stations are often seen occupied or evidence of recent use is seen.

 

2. (The implied question of monumentation rates.) The NGS database certainly does have a large decline in the number of PIDs monumented per year. However there are very recent monumentations of disks that are not in the NGS database. It could be that local databases have become more useful in recent years as compared to decades ago, or perhaps more to the point, local reliance on the national database may have become less for some reason. There is also a saturation effect - with over 700,000 NGS stations around, setting more is less important than when there was a lot less stations around.

 

3. Some disks were monumented for early and later mapping purposes that are now no longer as generally needed. Many of the mountaintop disks were put there to replace holes drilled in the 1800's for initial mapping of the area, but these days, to build a new McDonalds or a municipal building, it is not nesessary to take a reading from a 1890 mountaintop station 20 miles away; instead a 1960 station down the street can be used. The 1960 station was probably established for building purposes, not mapping purposes.

[+Shorelander]

I think part of it has to do with the jurisdiction and their habits as well. In Massachusetts, for instance, I haven't noticed new disks submitted to the NGS. But walk around downtown and you will see dozens of small disks set for the Big Dig - I waymarked as many as I could, just over 50 of them. So they are definitely setting new disks in Massachusetts - they're just not getting into any publicly-facing database that I could find.

 

I can understand why GPS has taken off, though. I can't imagine how much trouble it would be to occupy TU1210 for instance.

[+Renegade Knight]

The Board of Professional Engineers & Land Surveyors is so convinced that land corners (not exactly NGS but related just the same) are so vitally important that we are now required to show all corners in the vicinity of our plans, on our plans. Not just the ones we reference. The goal being better preservation since they tend to come up MIA.

 

Control is important. So much so that there are a lot more than one way to skin the cat these days.

Edited September 11, 2008 by Renegade Knight

[AZcachemeister]

 

I can understand why GPS has taken off, though. I can't imagine how much trouble it would be to occupy TU1210 for instance.

 

While that one is listed as a benchmark disk, it's pretty clear that it's an intersection station, and there is no disk set there! (Not the first time I've seen that error...)

 

If there IS a disk, you can bet it was occupied when it was set!

[+Shorelander]

 

I can understand why GPS has taken off, though. I can't imagine how much trouble it would be to occupy TU1210 for instance.

 

While that one is listed as a benchmark disk, it's pretty clear that it's an intersection station, and there is no disk set there! (Not the first time I've seen that error...)

Hehe, yeah, that's what I meant. Going to the trouble of finding the intersection of the diagonals of the building (especially now that it's received a few additions) would just make me want to go find another station to use.

[+shorbird]

Papa Bear,

 

Your picture is a perfect illustration of how benchmarks are used. Thanks for the post!! That picture should be on the main page for benchmarks here.

 

shorbird

[+89SC]

I was out on Rt 50 east of Grafton, WV looking for benchmarks Saturday and found two that showed signs of use.

 

JW1099 had a wooden stake with red ribbons beside it and red ribbons in the bushes above and below:

 

 

JW1100 had a wooden stake with orange ribbons beside it: