Coordinate Systems
MGA2020 (Australia)
Map Grid of Australia 2020 (MGA2020) is the standard projected coordinate system for construction and surveying work in Australia. SiteView supports MGA2020 natively across all measurement tools, the calculator, CSV import/export, and DXF export.
What is MGA2020?
MGA2020 is a Transverse Mercator projection based on the Geocentric Datum of Australia 2020 (GDA2020). It divides Australia into zones and converts geographic coordinates (latitude/longitude) into flat grid coordinates (Easting/Northing) measured in metres.
Grid coordinates are essential for construction because they allow you to work with flat distances and right angles on a 2D plan, which is how most engineering design and setout work is performed.
ℹ️ Did you know?
GDA2020 replaced the older GDA94 datum (and its MGA94 grid) in 2020. The difference between GDA94 and GDA2020 is approximately 1.8 metres in most parts of Australia, reflecting tectonic plate movement. SiteView uses GDA2020/MGA2020 — if you have older GDA94 data, it will need to be transformed before use.
Zones
MGA2020 uses zones that are each 6 degrees of longitude wide. Australia is covered by zones 49 through 56:
| Zone | Central Meridian | Longitude Range | Approximate Coverage |
|---|---|---|---|
| 49 | 111 E | 108 - 114 E | Western WA coast, Cocos/Christmas Islands |
| 50 | 117 E | 114 - 120 E | Central and southern WA (Perth, Geraldton) |
| 51 | 123 E | 120 - 126 E | Eastern WA (Kalgoorlie, Kimberley), western NT |
| 52 | 129 E | 126 - 132 E | NT (Darwin), western SA |
| 53 | 135 E | 132 - 138 E | SA (Adelaide), far western NSW |
| 54 | 141 E | 138 - 144 E | VIC (Melbourne), eastern SA, western NSW |
| 55 | 147 E | 144 - 150 E | NSW (western Sydney), ACT (Canberra), eastern VIC, TAS |
| 56 | 153 E | 150 - 156 E | QLD (Brisbane, Cairns), eastern NSW (Sydney) |
Choosing the Right Zone
Use the zone that covers your construction site. If your site sits near a zone boundary, either adjacent zone is valid, but you should use the same zone as your project's engineering drawings and survey control.
💡 Tip
Check which MGA zone your project surveyor is using and match it in SiteView. Mixing zones within a project creates coordinate mismatches that are difficult to diagnose.
Coordinate Format
MGA2020 coordinates consist of:
- Easting — the distance in metres east of the zone's false origin (e.g., 502341.234 E)
- Northing — the distance in metres north of the equator (e.g., 6962153.456 N)
- Zone — the zone number (e.g., Zone 56)
Typical value ranges:
- Easting: 100,000 to 900,000 (the false easting is 500,000 at the central meridian)
- Northing: varies by latitude, but typically 5,500,000 to 8,500,000 for mainland Australia
How SiteView Auto-Detects MGA Zone
When you interact with coordinates on the CesiumJS map, SiteView automatically determines the MGA2020 zone from the longitude of the location:
- The longitude of the clicked point or GPS position is checked
- The zone whose central meridian is closest is selected
- The Easting and Northing are calculated for that zone
For CSV import and batch conversion, zone detection works similarly — SiteView analyses the coordinate values and selects the most likely zone. See Auto-Detection for the full detection logic.
Using MGA2020 in SiteView
Measurement Tools
All measurement tools can display coordinates in MGA2020 format. When you click a point on the map, the coordinate readout shows the Easting, Northing, and Zone alongside WGS84 values.
Calculator
The Calculator accepts MGA2020 input for all calculation modes. Enter Easting/Northing values and the calculator converts to other formats automatically.
CSV Import and Export
When importing CSV files, SiteView detects MGA2020 coordinates from value ranges. When exporting, you can choose to include MGA2020 columns. See CSV Import and CSV Export.
DXF Export
DXF files are exported in MGA2020 grid coordinates for direct use in Australian CAD projects. See DXF Export.
Setting MGA2020 as Your Default
You can set MGA2020 as your default coordinate display format and specify a default zone in Coordinate Settings. Once set, all coordinate displays throughout SiteView will show MGA2020 values by default.
ℹ️ Did you know?
Setting a default does not prevent you from viewing coordinates in other formats. You can always switch between WGS84, DMS, MGA2020, and NZTM2000 in any tool — the default simply controls the initial display format.
What's Next?
- NZTM2000 (New Zealand) — the equivalent grid coordinate system for New Zealand
- Auto-Detection — how SiteView detects coordinate systems from values
- Coordinate Settings — configure your default coordinate format and zone
- Coordinate Converter — convert between MGA2020 and other systems