For all survey's completed in accordance with the Surveying and Spatial Information Regulation 2017, please refer to this page.
Datum line
The datum line for a survey must be adopted in accordance with section 28Surveying and Spatial Information Regulation 2024. The orientation of the datum line must be derived from accurate MGA co-ordinates using only permanent marks or reference marks, see section 28(3)(a)Surveying and Spatial Information Regulation 2024. Further information may also be found in the Surveyor General’s Direction – No. 7.
Urban and Rural Survey
All urban and rural survey plans must have an orientation adopted from MGA co-ordinates.
For both, the surveys must use 2 established survey marks within 1500 metres of the land surveyed and the datum line must be adopted from the grid bearing derived from the MGA coordinates of those marks.
The survey marks adopted for the MGA orientation must be directly connected, by close loop;
- To each of the other permanent marks or reference marks adopted for an accurate MGA orientation, and
- To different corners of the land surveyed
The grid bearing for the MGA orientation must be confirmed by angular and distance connection to a third survey mark that has accurate MGA coordinates.
If confirmation of the measured datum line exceeds 40mm + 200ppm the survey must connect to at least 1 additional permanent survey mark or reference mark that has accurate MGA coordinates, see section 28(5) Surveying and Spatial Information Regulation 2024. See also Surveyor General’s Direction – No. 7 .
Recording the datum line
Section 62 Surveying and Spatial Information Regulation 2024 indicates the method for recording the datum line. The terminals of the datum line must be shown by distinguishing characters on the face of the plan and these characters must be identified in the survey certificate. If the terminals are permanent survey marks the reference PM (number) or SSM (number) will be sufficient. If the terminals are another survey mark it is recommended that they be identified by an alpha character e.g. “A and B” or “X and Y”.
The datum line must show the scaled ground distance calculated from the co-ordinates compared to the distance measured.
All NSW legislation can be accessed at www.legislation.nsw.gov.au/
Publication Date: March 2025