ICSM Chair Michael Giudici provides an update on the modernisation of Australia’s Datum.
Earlier this year I provided articles for Spatial Source and Position Magazine outlining the steps in the process of updating Australia’s Datum, from GDA94 to GDA2020. At that time it was expected that the official release of GDA2020 would occur in March / April 2017. A vital component of the release is the national NTv2 distortion grid to transform between GDA94 and GDA2020. Appropriately modelling the distortion across the highly variable spatial distribution evident in jurisdiction survey control networks has proven to be very challenging. It has required a bespoke solution be developed, which is now near completion.
Read More: GDA2020 gears up to reshape Australian positioning
In addition, discussions with the National Measurement Institute (NMI) have been ongoing in relation to the final gazetting of GDA2020 as the new Recognised Value Standard of Measurement of Position. Prior to scheduling that activity, it has been necessary to release the first version of the new GDA2020 Technical Manual which has been forwarded to the NMI to support finalisation of the process.
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 early August. 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.
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, and 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”.
With Datum issues being grappled with globally, it is worth noting that Australia’s development work is being noticed internationally. In August, the ICSM’s ‘Modernising Australia’s Datum ’ animated video was featured in a talk on coordinate reference system support in QGIS at QGIS 2017 Nodebo, the 3rd User Conference and Developer Meeting in Denmark.
In summary, this is a challenging implementation, but Australian jurisdictions are committed to progressing the move to GDA2020 in as smooth a manner as possible.
In future updates I will provide a schedule of other activities and events that we will be participating in, particularly as we approach a more definite timeline for the technical product release. That’s where the online GDA2020 Forum and expert user community will come into its own in terms of assisting practitioners to consider implementation plans for their organisations and clients.
Until then, stay tuned…
