logging NGS benchmarks that are structures

[+st_moose]

I logged my first NGS benchmark that was a structure (a water tower in this case, because it was next to a 'regular' NGS disc) and I was wondering how others would log the benchmark.

 

Mostly I don't understand how a surveyor would use a structure as a benchmark

 

thanks

[AZcachemeister]

I logged my first NGS benchmark that was a structure (a water tower in this case, because it was next to a 'regular' NGS disc) and I was wondering how others would log the benchmark.

 

Mostly I don't understand how a surveyor would use a structure as a benchmark

 

thanks

 

You're in the wrong forum, try the Benchmarking forum!

 

To answer the question, a water tank/antenna/church steeple benchmark is called an Intersection Station. It's co-ordinates were obtained by surveyors sighting on the structure from many (at least three) other known locations, and the numbers are derived by triangulation.

 

Conversely, if you are at an unknown location, you could sight on several intersection stations and derive your location by triangulation (to a certain degree of accuracy).

 

See the Benchmark Hunting page and read the FAQ there for lots more information.

 

EDIT: To add the bit on how triangulation stations might be used.

Edited February 13, 2010 by AZcachemeister

[Keystone]

I am moving this thread from the Geocaching Topics forum to the Benchmarking forum.