NavList:

Bruce,

The benchmark on my land is a secondary USGS BM.  It was used ( to the best of my knowledge ) in the 40's to do a new triangleation of Wyoming.   It is no longer maintained or used by the USGS.

Eight or nine years ago the company my son-in-law works for bought a new, hi-tec GPS, radio survey thing-of-a-jig and he wanted to play with his new toy so he located the cooridants of my benchmark down to the second.  Not offical, but for me.

The grid system used in the states is for land ownership and is not based on latitude and longitude.  It is based on a defined monument ( benchmark ) and then measured in six mile squares, each with 36 one mile sections.  The squares are counted north-south and east-west from the starting point in what are called Ranges and Townships.  My home in Nebraska is legaly defined as so many feet and bearing ( true ) from the south west corner of the south west section of Range 23 west and Township 17 north of the sixth prime mederian.  No where is my land ownership defined by lat and long.  The physical location of the benchmark is the legal point even if the recorded coordinates are wrong.

As my son-in-law tells me - he is NOT a geodesist, he is a surveyor.  He never ( seldom ) works in lat and long.  He uses GPS and lat and long but only to help find things.  There are many different map grids that may or may not line up but the physical monument is King, not what the recorded location is.

John H.