Benchmarks

[Geo-Joe-N-Josh]

What is a Benchmark? Anything will help.

[Neos2]

Try this "read Me first" thread on the benchmark forum.

 

A benchmark is a permanent marker placed by some official group to help with surveying. Many of them are imprinted round brass markers set in concrete 'stands' but there are other kinds as well (chiseled marks, water towers, etc. One near me is an angel statue on the top of the entrace to a cemetery).

 

Some are placed exactly where the cords are, others are just rough estimates. That thread will get you started.

Edited February 6, 2008 by Neos2

[+Kewaneh & Shark]

From the GC.com Benchmark page & FAQs:

 

What is a benchmark?

A benchmark is a point whose position is known to a high degree of accuracy and is normally marked in some way. The marker is often a metal disk made for this purpose, but it can also be a church spire, a radio tower, a mark chiseled into stone, or a metal rod driven into the ground. Over two centuries or so, many other objects of greater or lesser permanence have been used. Benchmarks can be found at various locations all over the United States. They are used by land surveyors, builders and engineers, map makers, and other professionals who need an accurate answer to the question, "Where?" Many of these markers are part of the geodetic control network (technically known as the National Spatial Reference System, or NSRS) created and maintained by NOAA's National Geodetic Survey (NGS).

 

A word of warning: don't try to digest the whole Benchmark FAQs at one time. It may overwhelm you. If you have any questions about the benchmarks (or any other survey marks) you find, ask them in the benchmark forum. There are many knowledgable people there to help.

 

- Kewaneh

Edited February 6, 2008 by Kewaneh & Shark