Adopting Geocentric Datum of Australia 2020 (GDA2020)

The ACT is adopting the Geocentric Datum of Australia 2020 (GDA2020) for all its surveying, mapping and spatial data. The official projection for the ACT shall be the Map Grid of Australia 2020 (Zone 55).

Adopting a single projection in the ACT will rationalise the ACT mapping systems and integrate the ACT spatial data with the rest of Australia, particularly NSW which totally surrounds the territory.

For more information about how Australia is moving to a new geodetic datum, visit the Intergovernmental Committee on Surveying and Mapping (ICSM) website.

SDMS and ACTmapi

From late 2020, fundamental data for the ACT stored in the Spatial Data Management System (SDMS) and published on ACTmapi will be in GDA2020.

Information for surveyors

Any data submitted to the Office of the Surveyor-General and Land information must continue to be in ACT Stromlo Grid until further notice.

Survey practice guidelines for transitioning to and working with GDA2020 are being prepared.

Information for spatial data managers and users in the ACT

Spatial data managers in ACT Government will need to consider transforming their data to GDA2020, particularly for data in ACT Stromlo grid.

Note that spatial data may not necessarily need to be transformed. Where the data has lower spatial accuracy it may be compatible with GDA2020 as the shift from GDA94 to GDA2020 is approximately 1.8m.

How to transform data to GDA2020

From GDA94

See the tools on the ICSM website.

From ACT Stromlo Grid

To transform from SGC (AGD66) to MGA2020 (GDA2020), apply the following 7 figure transformation parameters (EPSG Registry Code EPSG::9185):

X axis Translation (tx) -136.9703 Metres (m)
Y axis Translation (ty) -37.5638 Metres (m)
Z axis Translation (tx) 124.4242 Metres (m)
X axis Rotation (rx) -0.25676 Arc-seconds
Y axis Rotation (ry) -0.42966 Arc-seconds
Z axis Rotation (rz) -0.30077 Arc-seconds
Scale (sc) -4.61966 Parts per million (ppm)

For further information, including transformation parameters for PGC coordinate systems, please email