Australia’s geodetic datum is changing. The introduction of GDA2020 means a huge step forward in in the advancement of location-based technologies. But what does this mean for surveyors?
The Intergovernmental Committee on Surveying and Mapping (ICSM)’s GDA2020 Implementation Team have released a video, titled ‘Modernising Australia’s Datum’ explaining how and why Australia’s geodetic datum will be upgraded from 2017.
Surveyors use the current datum GDA94 to determine coordinates of geographical features so they can be plotted on a plan and used for projects such as land subdivisions.
Australia’s current datum, GDA94 is fixed to the country’s tectonic plates. As our plates move, location-based technologies that use satellite positioning systems such as GPS will become less accurate. Since GDA94 was introduced in 1994, Australia has moved 1.5 metres and the gap will continue to widen.
With an increasing reliance of modern technologies on geographic data, it is vital that our datum is continually updated and accurate. The ICSM website explains that “the need to modernise Australia’s national spatial reference system is critical to ensure confidence in Australia’s spatial information now and into the future.”
GDA2020 is a new datum, which will shift coordinates by approximately 1.8 metres so as to align the projected International Terrestrial Reference Frame (ITRF) in 2020. Once the coordinates are aligned, the Australian Terrestrial Reference Frame (ATRF) will become dynamic, meaning moving coordinates can be tracked and updated in real time. GDA2020 and the ATRF will work in conjunction, providing accurate data, tailored to the user’s requirements.
Stage one of GDA2020 is the introduction of the new plate-fixed datum which will commence January 1, 2017. Stage two is the dynamic datum, which will begin to roll out in 2020 and is set to be fully implemented by 2023.
According to ICSM, the modernised datum will improve accuracies of existing spatial datasets and precise positioning systems to under 3.0 metres.
Location-based data will be significantly more accurate, impacting industries that rely on global coordinate reference systems including telecommunications, transport, agriculture and construction.
Surveyors use technologies that use the Continuously Operating Reference Station (CORS) network or Airborne Laser Scanning Systems (LiDAR). These systems will be updated with the new GDA2020 data as of 2017. Then when the dynamic datum is introduced, coordinates can be more accurately calculated by surveying technologies, many of which rely on GPS.
The long term effects of more accurate spatial data is an exciting development for surveyors, however, some adjustments will need to be made. The ICSM explains further, “Members of [the spatial information] community will need to be clear about what processes are required to transform between different datums. For those that are involved in the measurement and exchange of spatial information they must ensure they know what datum spatial information has been captured on, and where appropriate, deliver and store spatial information with appropriate metadata to ensure that this knowledge is retained with the data.”
Visit the ICSM website to find out more about how the changes will impact you.
