Survey marker

All sorts of different objects, ranging from the familiar brass disks to liquor bottles, clay pots, and rock cairns, have been used over the years as survey markers.

Today in the United States, the most common geodetic survey marks are cast metal disks with stamped legends on their face set in rock ledges, embedded in the tops of concrete pillars, or affixed to the tops of pipes that have been sunk into the ground.

These marks are intended to be permanent, and disturbing them is generally prohibited by federal and state law.

[2] Survey markers in Nagoya, Japan, which bear stylized images of shachihoko, are noted for their elaborate design.

It was often marked by a "station disk" (see upper photo at left), a brass disk with a triangle inscribed on its surface and an impressed mark that indicated the precise point over which a surveyor's plumb-bob should be dropped to assure a precise location over it.

Estimated coordinates are termed "scaled" and have usually been set by locating the point on a map and reading off its latitude and longitude.

Current best practice for stability of new survey markers is to use a punch mark stamped in the top of a metal rod driven deep into the ground, surrounded by a grease filled sleeve, and covered with a hinged cap set in concrete.