Benchmarks

[+ladeebugg]

I had never heard of a benchmark till i started geocachin. What is a benchmark? Who put them there, and what is their purpose? And what do you do when you find them? Ive got a few to look for that are close to home, figured when there wasnt a cache close, benchmark would do. Thanx Guess these are stupid questions, was hoping, someone would enlighten me, Thanx

Edited January 11, 2006 by ladeebugg

[+Kewaneh & Shark]

In short, a benchmark is a land survey reference point. They are used in various types of land survey and engineering projects as horizontal and vertical referencing. True benchmarks are for vertical measurement, ie elevations. Triangulation stations are used horizontal positioning on the ground. Many marks are now used as both types, even though the marks were usually placed with only one intended purpose. On GC.com, both type of marks are called 'benchmarks'.

 

From the Benchmark Hunting FAQs

 

What is a benchmark?

 

Geodetic control points are permanently affixed objects at various locations all over the United States to enable land surveying, civil engineering and mapping to be done efficiently. These objects are usually metal disks, but can be any other object that serves as a control point.

 

There are two general types of these control points:

 

One type, the vertical control point, is for precisely establishing the elevation at that point. This type of control point is usually, but not always, a small brass or aluminum disk, concrete post, iron pin, or bolt, (among other things), that is permanently attached to a stable foundation.

 

The other general type of control point is for horizontal control. There are several names for horizontal control points - triangulation stations, traverse stations, trilateration stations, GPS stations, and intersection stations, depending on which kind of horizontal control system was used in establishing them and the amount of precision they represent. This type of control point can be a small brass or aluminum disk, concrete post, iron pin, or bolt, (similar to the vertical control points) but also radio towers, water towers, church spires and mountain tops or any other type of object that can be identified from a distance.

 

In the surveying profession, the term benchmark is applied only to the vertical control type, but for sake of discussion on the Geocaching website, both vertical and horizontal control points are commonly referred to as benchmarks.

 

These markers are part of the geodetic control network created and maintained by the National Geodetic Survey (NGS). The NGS maintains a database of these locations. In the database, each geodetic control marker has a PID (Permanent IDentifier) number, and a datasheet of information about it. Although much of the descriptive (how to find it) data is outdated, the surviving markers remain vitally important to the conduct of our nation's commerce.

 

- Kewaneh

[+Black Dog Trackers]

ladeebugg -

 

Welcome to Benchmark Hunting!

 

Before you start looking for benchmarks, be sure to read all of the Benchmark Hunting FAQ that Kewaneh & Shark referenced.

 

Also, check out a few found logs that people have done. They will be the ones with an exclamation mark in the leftmost column in a Nearest Benchmarks in a geocache page, Postal Code, or Coordinates search done from the Benchmark Hunting FAQ page.

 

Also, check out the Benchmark Gallery to see what you'll be looking for.

[Photobuff]

Ladeebugg-

 

Yes, welcome! Whatever you do, do not attempt to find a benchmark. It seems innocent enough on the surface, but what are you going to do if you find one. Yup, that's right, you're going to look for another. And another. And maybe just one more after that. You tell yourself you can quit anytime you want to, but deep inside you know the truth. It's an addiction and a disease with few cures. Part of vacation preparation will be checking to see what benchmarks are near your destination. Trips to nearby places will be interrupted for "just a quick stop to look for NBxxxx". Suddenly your hard drive will be littered with images of topo maps and aerial photos. You'll be talking to people you'd never otherwise meet- I just drove in and introduced myself to two local farmers to get permission to wander in their fields, and ended up chatting about local history for at least an hour. You'll end up wanting a metal detector, a probe rod with a more comfortable handle, and a longer tape measure. A lot longer! You'll catch the history bug and want to learn about surveying and the USC&GS and all the changes your local region has gone through over the years. You may yearn for simpler time. Save yourself while you can

[+Crystal Sound]

Dont forget the visions.... For instance, you drive along a road, and spot one in a bridge abutment... Or spotting an "innocent enough" round concrete post, along the side of a rural highway. Somebody please, make them stop!

 

Welcome to the hobby/obsession/whatever you like to call it.

[+seventhings]

And you will begin to fantasize about a small town in the Midwest. It has a county courthouse set on a tree-lined square. There's a flagpole and a Civil War mounument. There are also seven prominent church-spires, two water tanks and three tall factory stacks. There are four WPA-era bridges east of town and two west of town, and a large public park on a hill. On the outskirts of town, there are miles and miles of wide-shouldered, two-lane blacktop that has not been re-paved since 1929. You will imagine yourself doing a radial search on the courthouse and seeing four pages of un-found marks within three miles. Then, you'll start scouring mapping software to find such a place. When you do find it, you'll start making vacation plans.

 

Years ago, a wise man said "If you monument them, they will come."

 

My name is William, and I'm a benchmark hunter.

 

Abandon all hope, ladeebugg.

 

Will

Edited January 13, 2006 by seventhings

[ArtMan]

What about the railroad, 7? Town like that gotta have train service, no?

 

But this gets me wondering — where might one find the densest concentration of marks, say the most within a given radius or a rectangle of given dimensions.

 

Here are a few examples, using the radial search function on the NGS website to find all marks within three miles of ...

 

WASHINGTON MONUMENT 1913 (HV4442) — 770 marks (27.2 per sq. mi.)

BOSTON STATE HOUSE CUPOLA (MY3299) — 488 marks (17.3 per sq. mi.)

ATLANTA CITY HALL SPIRE (DG2684) — 342 marks (12.1 per sq. mi.)

EMPIRE STATE BUILDING (KU3602) — 240 marks (8.5 per sq. mi.)

CHICAGO SEARS E TV TOWER (ME2805) — 149 marks (5.3 per sq. mi.)

Philadelphia CITY HALL (JU3112) — 134 marks (4.7 per sq. mi.)

ST LOUIS COURTHOUSE (JC1598) — 65 marks (2.3 per sq. mi.)

 

I knew the DC area was heavily benchmarked, but the dramatic difference in density is, well, dramatic. Obviously, not a scientific sampling or anything, and I wonder if there is a more systematic way of examining this, or if it matters....

 

-ArtMan-

[holograph]

A while back, I tallied benchmarks by USGS quad. Washington, DC won by a fair margin. Here were the top ten quads:

Count Quad
----- ------------------
811  WASHINGTON WEST (Washington, DC)   
680  CAPE CANAVERAL (Brevard Co., FL)   
583  NAPA (Napa Co, CA)                 
526  NEW ORLEANS EAST (Orleans Co., LA) 
491  BOSTON SOUTH (Suffolk Co. MA)      
454  LONG BEACH (Los Angeles Co., CA)   
448  ST PETERSBURG (Pinellas Co., FL)   
412  PORTLAND (Multnomah Co, OR)        
407  ALEXANDRIA (Fairfax Co., VA)       
407  HOLLYWOOD (Los Angeles Co., CA)    

[+seventhings]

Art -

 

Of course the town has a railroad. No, wait, it has two! And both have been converted to trails but all the bridges have been preserved and the crossings have not been re-graded since 1937.

 

And, against all odds, there's a lighthouse in the middle of the park on the hill.

 

W

Edited January 13, 2006 by seventhings

[+PFF]

When I was a teenager, a friend ruined movies forever by showing me the "change reel" dots in the corner of the screen. Now, I cannot ignore them.

 

Then I discovered aluminum triangles on telephone poles beside the highway. I never noticed the things until I got into this hobby. Now, I'm afraid I will run off the road looking for......Wait! Was that a witness post we just passed? Stop the car!

 

-Paul-

[Wintertime]

A while back, I tallied benchmarks by USGS quad.  Washington, DC won by a fair margin.  Here were the top ten quads:

Count Quad
----- ------------------
811  WASHINGTON WEST (Washington, DC)   
680  CAPE CANAVERAL (Brevard Co., FL)   
583  NAPA (Napa Co, CA)                 

Napa? Napa?? Why on earth would there be so many benchmarks around Napa?

 

Patty

[ArtMan]

7-

 

And, of course, a small general aviation airport with a friendly operator, little traffic and no security. Not far from the abandoned beacon (with concrete arrow). You can see it from the fire tower across town from Lighthouse Hill.

 

Isn't there a production of "Our Town" this weekend at the high school (the one with the cupola)?

 

-ArtMan-

Edited January 13, 2006 by ArtMan