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Brand Newbie - A Few Questions


EZEnos

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Howdy,

 

I am brand new to this website and to the 'sport' of benchmark location. I find the idea of locating benchmarks fascinating and I just have a few questions that I was wondering if ya'll could help me out with.

 

Firstly, I don't have a GPS right now. Is it possible to find benchmarks using only the engineers description? If a benchmark is located in this manner, does it call into question the accuracy of the find?

 

Second, once I find a benchmark, then what? Do I just 'log' it here under my own account, or should I also report it to a government organization?

 

And lastly, any one else benchmark hunting in Las Vegas? I've looked over a couple of zipcodes here in Vegas and pretty much all the marks are open.

 

Thanks for any insights you might have.

 

Nathan Enos

nate@lasvegasdirectory.com

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Hi, welcome to benchmark hunting! Unlike geocaching, an additional challenge is that what you seek might not be there anymore.

 

Here are answers to your questions.

 

1. It is possible to find benchmarks without a GPS. In fact, the descriptions are pretty much made to find the marker without needing a GPS. In urban areas, a GPS is really not needed at all. In open country, a GPS might help quite a bit so that you don't have to measure 300 yards, etc. Generally though, benchmarks are very near landmarks, unlike geocaches. You can also use a satellite map from the internet to give you a good idea where the station is located if you have no GPS.

 

2. The accuracy of the find depends not on how you found the marker, but instead depends on whether the name stamped on the marker you find matches the marker's "Designation" on the sheet from the website for the benchmark.

 

3. After getting home, log your find into the Geocaching website with your account. If there's no report for the last 30 years or so, you could consider reporting a find to the NGS site, expecially if some aspects of the location description have changed. Take notes when you're there!

 

4. If the benchmarks in your area are open, GO for it - you're the first one of us looking there!

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In fact, Vegas is an ideal place for this. There are a lot of tri-stations not only in the city, but in the mountains surrounding the valley, and most of them are relatively new. Nevada, due to its remote and inhospitable expanse, was among the last areas of the country to be covered by the national control network, so most of the monumentation there is post-war era. The absence of development outside the Vegas Valley means virtually all of the points are still there. Also the markers set in the mountains overlooking the city remain safe even as the city expands. If you visit Jet, Snipe, Len, Happy, Can, Pipe, Bard, Jerk, Dodo2, Whitney2 or BMW51, you will be walking in my footsteps. BMW51 would be a good easy one to start with, its just down Boulder Hwy. from Sam's Club, unless they widened it again recently, it was close to the road 15 years ago.

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quote:
Originally posted by survey tech:

If you visit Jet, Snipe, Len, Happy, Can, Pipe, Bard, Jerk, Dodo2, Whitney2 or BMW51, you will be walking in my footsteps.


 

OK, I want to know what happened to cause someone to name a benchmark "JERK" icon_smile.gif

 

-Centaur

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quote:
Originally posted by survey tech:

If you visit Jet, Snipe, Len, Happy, Can, Pipe, Bard, Jerk, Dodo2, Whitney2 or BMW51, you will be walking in my footsteps.


 

OK, I want to know what happened to cause someone to name a benchmark "JERK" icon_smile.gif

 

-Centaur

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i actually just started looking for benchmarks TODAY, (with no GPS) out of the 5 i printed to look for, I found 2. I would consider it 3, but poison ivy kept me kinda far from seeing if it was actually there. I took some digital pics of the disks and posted them with my logs.

 

anyway, what i posted to say is that the ones i did find were easy enough to do with no gps.

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I wish that they were all that easy over here in the Ozark hills, I have found quite a few without the GPSr but most of them sit high in the air.There are some down here in the Forests that you have to have one to findem.Some coordinates from the original surveys are different than the things that we are looking at today, 1. The Magnetic field has moved approx. 7.5 degrees in the last 142 years of keeping records, the North Star,Polaris, is slightly moving to the west as well, annual wesward slippage,or the expasion of the Universe as the Scientists are now calling it.

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quote:
Originally posted by Trailblazer # 1:

I wish that they were all that easy over here in the Ozark hills,


 

I will admit that it is a whole lot easier when the description references street names. Occansionally I get a difficult one but usually because of recent construction. Still, I get to parts of the area I've never been to before so it remains very interesting every time I go out.

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That is the fun just getin out there and lookin for em you know, dosent matter how u findum.The one that I have been finding are highly accurate to the readings given, there are still those that are very puzzling because none of the data is now correct??? and those with no data , you never know what you may stumble upon in the forest, and especially in the CITY, i'll take my chances in the woods!!!!

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With the exception of those markers which only have approximate coordinates, all coordinates and other data provided on the NGS data sheets are intended to be permanent and remain correct over time. Polaris, which is currently known as the north star, due to the fact that it happens to be very near the point in the heavens that corresponds to true north at this time in history, moves through an infinitely repeating cycle that takes it away from this point in the heavens, and then back around to it, about once every 26,000 years. During each cycle, several other stars take turns being the north star, the brightest of which is Vega, in the constellation Lyra, which is near the other end of the cycle, now over 50 degrees away from true north, which will again become the north star about 13,000 years from now. This movement is known as apparent motion, since the stars are not really moving, but merely appear to move when viewed from this planet. So astronomical north, upon which the data is based, remains unchanged over time, while the positions of the various stars with respect to it are constantly changing and can be precisely calculated at any moment in time. Anyone interested in this may want to order a copy of The Star Almanac For Land Surveyors, available in North America from Berman-Unipub of Lanham MD for about $30, which is an ephemeris giving positions of all the bright stars for each year.

 

The different datum information given on the data sheets represents adjustment of the positions of the points in the network, due to technological improvements in the determination of the exact size and shape of the planet, which improvements will probably continue in the future, leading to further adjustments, but this process does not have anything to do with orientation to true north, which is unchanging, nor does it represent movement of the points or error in the original calculation. Also, while crustal movement of the earth may make some coordinates inaccurate, particularly in areas where earthquakes often occur, magnetic variation has no impact whatsoever on the data, since the data is unrelated to magnetic north. Incidentally, use of a magnetic compass for land surveying has been banned by BLM policy for over a hundred years now.

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The Earth's rotational axis precesses in a 26,000 year cycle, currently pointing near Polaris and making a circuit of stars and back to Polaris.

 

The Earth's axis of revolution around the sun has it's own pole in relation to the stars and this also precesses in a 41,000 year cycle, causing it to mark out a different circle among the stars from that of the precession of the rotational axis. No doubt the solar system's revolution around the center of our galaxy precesses as well.

 

There is no unchanging astronomical North.

 

All stars move in relation to each other, causing the constellations to change shape over time. Polaris won't always be in the circuit of stars that Earth's precessing pole describes; it will move away.

 

The Earth's continents slide around over the Mantle in respect to the Earth's rotational axis. This is called 'apparent polar wandering'.

 

The Earth's rotational pole moves as well. It has a wobble that completes a circuit of 6 meters in 435 days.

 

As the Earth's crust moves, the Earth's rotation axis in relation to the Mantle moves to compensate for these movements. This is called 'true polar wandering'.

 

The relationship between a benchmark and any type of North-South axis you may choose (rotational pole, magnetic pole, geographic pole, Earth orbit pole, solar system orbit pole) is always changing.

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