PM58058 Bass Hill, New South Wales, Australia
By Geocaching Australia on 18-Feb-13. Waypoint TP6631

Bankstown Testline Pillar 4

This trig like pillar (PM58058) is part of the 'Bankstown Testline' these are use for calibration of survey equipment, their position is known to within 2 millimetres.

A Trig Point is a virtual cache which requires a cacher to locate the Trigonometric Station at GZ.

A trig point (also known as a Trigonometric Station) typically consists of a black disc on top of four metal legs or concrete pillar, resembling a navigation beacon. It is also accompanied by a metal disc, which is located directly below the center point of the tripod or on top of the pillar itself.

Trig points are generally located at the top of hills or points of prominence in the landscape. Many provide unique views and challenges, with some being difficult to get to.

These points were regarded as valuable to surveyors, providing reference points for measuring distance and direction, and assisting in the creation of maps.

To log a find on the Geocaching Australia website, you will need to include a picture of the trig point, along with your GPS receiver and (preferably) yourself. Long distance / telephoto type pictures are against the spirit of this cache. You are encouraged to leave a description of your journey in your log to help others in finding the trig point.