To support the introduction of the Surveying Coordination Act and the requirement to connect to the grid, Australia introduced various map projections:
- Australian Geocentric Datum or GDA66
- Geocentric Datum of Australia
- GDA94
- GDA2020
- Intergraph 94
- VicGrid (VicGrid94) – chosen as a projection of choice for the state of Victoria mapping applications.
Guide to Map Projections
More information
GDA2020 and GDA94 Technical Manuals
You can use GDAIT windows application to transform coordinates between datum Australian Geocentric DatumnGD66 (AMG66) and GDA94 (MGA94)
You can also use AMGVG conversion software
Check Geolocalisation of address point for emergency services: Address Points for Emergency Services (mapshare.vic.gov.au)
For the address, 1 Treasury Place East Melbourne 3002, It lists coordinates in
Intergraph 94 (Ex X: 3 382 434.17, Y: 1 273 520.57)
VicGrid 94 (Ex X: 2 497 793.61, Y: 2 409 752.20)
GDA 94 (Ex X: 144.97494, Y: -37.81324 [ X=Longitude, Y=Latitude])
All coordinates are 7 digits. By introducing 8 projection zones, Australia can maintain to Easting coordinates of 6 digits.
A zone is 6 degrees of longitude wide. Victoria wide is about 9 degrees. West falls in the middle of Zone 54 and East tip of the state is at the end of Zone 55.
A guide to the mathematics of map projections by Rod Deakin
