GDA2020 at Locate ’18: a progress update

By on 26 March, 2018

The GDA2020 datum was formally gazzetted by the National Measurement Institute in October 2017.

This article was written by Michael Giudici, chair of the Intergovernmental Committee on Surveying and Mapping, and Tasmania’s Surveyor-General. Mr. Giudici will present on the GDA2020 implementation at the Locate ’18 – Geosmart Asia ’18 conference in Adelaide on April 10, and you have the opportunity to have your burning GDA2020 questions answered. See our earlier coverage: What do you want to know about our new datum?

This time last year I provided an overview of the reasons Australia was moving to a new datum, GDA2020. Since then, a large amount of technical work has been occurring, and all Australian jurisdictions have been gearing up for the change.

In October last year, the National Measurement Institute (NMI) formally gazetted GDA2020 as the Recognised Value Standard of Measurement of Position, meaning GDA2020 officially replaced GDA94 as Australia’s new datum.

Senator the Hon Matt Canavan, Minister for Resources and Northern Australia, noted in a December media release that the first update to Australia’s mapping coordinate reference frame for more than two decades has moved Australia’s coordinates approximately 1.8 metres to the northeast. “This movement is significant when it comes to applications that rely on highly accurate positioning, such as precision agriculture, the emerging intelligent transport sector, mobile location based services and automated mining operations,” he said.

The technical work on the development of the national NTv2 distortion grids is complete and the grids are available online. This has been a major complex technical achievement involving all the jurisdictions and Geoscience Australia. The release of the transformation tools has meant that CORS providers and software houses can now concentrate their efforts on assessing the integration of parameters into their products. It is expected that these processes will be commencing over the next few months.

Another major body of work has been an assessment of the legislative and administrative implications of adopting GDA2020 and ultimately the Australian Terrestrial Reference Frame. The report on this project, jointly funded by the Cooperative Research Centre for Spatial Information and ICSM, was accepted by ICSM in August 2017. While the full report was not prepared for public release, key findings will be communicated in a simple format.

The project considered how an Earth-fixed datum will be accommodated in spatial technology. Several global spatial technology powerhouses are working hard on this problem, and plan to include the transformation tools in future releases. These players, and the open source community, are also aware of the need for a consistent lexicon dealing with Reference Frames. They are aware of the need to develop an enhanced awareness of the nature of Reference Frames and Datums and how they are treated in their products. Similarly, the PROJ.4 library, the projection and transformation engine used by the majority of open source spatial software and web services globally, is being updated to accommodate Earth-fixed datums.

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At the ICSM Datum modernisation implementation team meeting held in Melbourne in August, I made the point that we have reached a natural transition stage for this national project. Most stakeholders have stopped asking ‘why?’, and instead are asking, ‘how?’ and ‘when?’ Furthermore, as the delivery of technical transformation products occurs, the focus will shift from the underpinning geodesy to the management of spatial data.

This isn’t unique to Australia. The US new datums program is the most well documented international instance of datum modernisation similar to that being undertaken in Australia. The National Geodetic Survey held its now bi-annual Geospatial Summit in April, presenting updates on the planned move from the North American Datum of 1983 and North American Vertical Datum of 1988. This modernisation will allow for the adoption of time-dependent horizontal and vertical reference frames in 2022. During the summit, presenter Dave Doyle remarked that unlike previous datum modernisation efforts, this time there was a huge user group from multiple stakeholder communities (not just the spatial community) “sitting on mountains of high accuracy data”.

In anticipation of an increased requirement for information products, ICSM has been preparing new fact sheets, called “Datum Matters”. At the date of writing, 5 fact sheets have been completed and are available on the ICSM datum pages. Additional fact sheets are under preparation and will be progressively uploaded to the website as they become available. These are designed to be used by those requiring simple explanations of datum issues, and are useful to hand out to clients and users who need to know there are changes happening.

For those who require detailed technical information such as transformation parameters and distortion grids, the GDA2020 Technical Manual is also available on the ICSM and Geoscience Australia Websites. We have also set up an online forum where interested parties can submit a range of question that will be addressed by subject matter experts that range across the fields of use.

I would encourage everyone to visit the ICSM website and review the latest information which is being progressively updated. There will be a special GDA2020 forum at Locate 18 in Adelaide in April during which a further demonstration of technical and implementation matters will be discussed. I look forward to meeting many of you there.

This article originally appeared in the February-March issue of Position magazine. 

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