An Electronic Distance Measuring (EDM) Base at Watson, located off Aspinall Street, is available to use for calibrating EDM units.


The Watson Base has 11 forced centring pillars over 1117 metres. The base is on a sloping site with a concave profile to ensure visibility between pillars. On top of each pillar is a brass plate fitted with a 5/8 inch UNC threaded bolt and a lockable cap fits over the top of each pillar.

The first four pillars are placed at chainages of 0m, 5m, 7.5m and 47.3m. The unit length of the EDM being calibrated will govern which two pillars are to be occupied. Temperature and pressure are recorded with each measurement. Higher precision calibrations can be made by occupying all stations and measuring all distances.


To calibrate EDM units, you can borrow from us:

Contact us to arrange use of this equipment.

Equipment assurance

Barometers and thermometers used in calibration activities are checked according to approved standards. A Certificate of Verification required by the National Measurement Act was issued for the Watson Base by the Commonwealth Surveyor General in 1987. This Certificate is renewed when the base is recalibrated in accordance with the requirements of the National Standards Commission's Working Party.