Regulation 6(1)(a) and (b) of the Surveying (Cadastral Surveys) Regulations 2015 requires a licensed surveyor to use survey equipment that has been compared to a standard of measurement. The process and basis of comparison must be adequate to obtain the accuracy required under the regulations.
Regulation 6(2) requires licensed surveyors to retain records of comparisons and make them available for inspection upon request by the Surveyor-General.
Comparison of EDM equipment
Surveyor-General of Victoria Practice Directives require Electronic Distance Measurement (EDM) equipment used on any survey to be calibrated:
- at intervals not exceeding 12 calendar months
- after every repair to all or part of such equipment
- by comparison to a baseline approved by the Surveyor-General.
To assist licensed surveyors to calibrate EDM equipment, the Office of Surveyor-General Victoria maintains an EDM calibration handbook, EDM calibration software, and six EDM calibration baselines in Victoria.
EDM calibration handbook
Meteorological transfer standard corrections
The Office of Surveyor-General Victoria maintains a 'transfer standard' temperature and pressure gauge. The transfer standard is calibrated against the national standards for temperature and pressure on a biennial basis. During the annual baseline calibration surveys, each of the 'baseline standard' thermometer and barometer devices is compared against the transfer standard. These comparisons are undertaken to monitor and record the offset of the baseline standard thermometer and barometer.
In order to ensure that readings from meteorological equipment used in instrument calibration are comparable to the national standards for temperature and pressure, the recorded offset for the baseline standard to transfer standard must be applied as a correction. These corrections are listed in the table below, and must be included on the instrument calibration booking sheet.
Table last updated 12/12/2017
Pulsed Instruments and instruments with a unit length of zero
For instruments with a unit length of zero and pulsed instruments, the meteorological observations must be entered into the instrument at the time of the calibration.
The unit length, frequency and carrier wavelength are used in the calculation of the meteorological corrections and cyclic errors within the Baseline software. Surveyors can enter the instrument into the register, leave all the details blank and the software will still process the data correctly.
Instrument parameter spreadsheets
The following spreadsheets list instrument specific parameters to assist surveyors when using the Baseline software to calibrate EDM equipment.
EDM calibration software
To assist surveyors to calibrate EDM equipment against standard baselines, an EDM calibration computer program called Baseline (Version 184.108.40.206, July 2012) has been made available for public use by the Western Australia's land information authority, Landgate. The Office of Surveyor-General Victoria has adopted this software for calibrating EDM baselines and EDM equipment in Victoria.
The latest version of Baseline and distribution file for calibrating EDM equipment against Victoria's baselines is available from the following link:
The distribution file available from this link is updated annually following the re-verification of Victoria's baselines. The EDM Calibration Handbook and online help provide the user with the necessary instructions to run Baseline.
The new version of Baseline has been prepared to overcome difficulties running on 64-bit versions of Windows 7. If users experience persistent runtime difficulties running Baseline on Windows 7, please contact geodetic survey via email@example.com.
Users who have obtained Baseline directly from Landgate must ensure they have the most up to date Victorian baseline information before reducing their results.
EDM calibration baselines
The Office of Surveyor-General Victoria maintains six EDM calibration baselines in Victoria: Bendigo, Braeside, Geelong, Hamilton, Cowwarr and Mitcham. As a verifying authority for length, the Surveyor-General of Victoria arranges for the re-verification of these baselines on an annual basis in accordance with the provisions of the National Measurement Act 1960 and National Measurement Regulations 1999.
Victoria's EDM calibration baselines and controlling offices
- Bookings are required in advance to use the baselines.
- Controlling offices are open between 8.30am and 4.30pm, Monday to Friday (except Bendigo which opens at 9.00am).
- Baselines are available for use on weekdays only.
- Users are required to have their own copies of official booking sheets.
- No rubbish is to be left behind.
- All gates must be left in their original position.
- Pillar caps are to be refitted upon completion.
- When using non-standard prisms, sighting difficulties may be experienced between pillars. The same type of prism must be used for the observations to achieve a valid calibration.
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