## What ellipsoid does GDA94 use?

## What ellipsoid does GDA94 use?

System 1980 ellipsoid

The Geocentric Datum of Australia 1994 (GDA94) is defined by the coordinates realised on the Australian Fiducial Network (AFN) geodetic reference stations, referred to as the Geodetic Reference System 1980 ellipsoid (GRS80), determined within the International Terrestrial Reference Frame 1992, at the 1 January 1994 …

**Is GDA94 the same as MGA94?**

GDA94 replaced the Australian Geodetic Datum 1966 (AGD66) and Australian Geodetic Datum 1984 (AGD84). The standard map projection associated with GDA94 is the Map Grid of Australia 1994 (MGA94), a transverse Mercator projection that conforms to the internationally accepted Universal Transverse Mercator Grid system.

### What is the difference between MGA and GDA?

All data in Australia should be now be recorded using a GDA coordinate system (either projected, or geographic coordinates). MGA is the Map Grid of Australia as applied to GDA94, in a projected coordinate system (as opposed to a geographic coordinate system).

**How is AHD calculated?**

By subtracting the value of the AUSGeoid09 model at the latitude and longitude of your house, you can compute the AHD height.

#### What is the difference between WGS84 and GDA94?

GDA94 is a coordinate system specifically for Australia. WGS84 is developed for the DMA or United States Defense Mapping Agency which is now called the National Imagery and Mapping Agency or simply NIMA. It is the main geodetic reference system used by GPS systems.

**What is AUSGeoid2020?**

AUSGeoid2020 has been developed to support the improved determination of AHD height estimates HAHD from GNSS observations. AUSGeoid2020 provides ellipsoid to AHD separation values NAHD onshore with uncertainty.

## What is the difference between GDA94 and GDA2020?

The difference between GDA94 and GDA2020 coordinates is comprised of a conformal transformation component primarily due to plate tectonic motion (Figure 1), and an irregular (non-conformal) distortion component.

**Is UTM same as MGA?**

UTM – Universal Transverse Mercator (The parameters are identical to MGA, therefore users often select UTM where MGA may not be an available option in their software or GNSS receiver setup menu).

### Is MGA a UTM?

The MGA projection is essentially the same as a UTM (Universal Transverse Mercator) projection of WGS84. If you are using a GPS, set the datum to WGS84, and the position format to UTM/UPS.

**What is the difference between GDA 1994 and GDA2020?**