GDA2020 Update - February 2021

GDA2020 Logo

Stage 3 of the Landgate GDA2020 Implementation Project is upgrading SLIP to be able to receive and provide data in GDA94 and GDA2020.

SLIP is now prepared to received data in GDA2020 from data custodians. We have also implemented updates to our Data Upload Tool (DUT) to capture extra metadata such as upload datum. This will enable SLIP to retain original data and metadata before any transformations are applied to store and publish data to web services.

Agencies like Department of Mines, Industry Regulation and Safety are already providing data in GDA2020, however most are still to transition and we encourage agencies to plan and communicate their own GDA2020 implementation as soon as possible. Contact opendata@landgate.wa.gov.au to share your implementation plan and progress to date.

Good metadata is more important now than ever! It is best practice for metadata to include information about the underlying datum of spatial data. Data Custodians should refer to the ANZLIC guidelines on preparing metadata for GDA2020 and AGRS.

Users must also take care to determine the Coordinate Reference Systems (CRS) of data, including the coordinate epoch, particularly when the CRS is dynamic like WGS84.

Additional datum information has been added to the SLIP Data Update API.

Example of Data WA metadata including Geospatial source projection.
See Data WA for source datum

When publishing data to Data WA, custodians are required to provide metadata and should also provide a supplementary Data Dictionary and detailed metadata statement.

The SLIP API is used by Data WA to update the ‘Data last updated’ and ‘Geospatial source projection’ fields for SLIP datasets.

A new SLIP data download solution is being designed to provide geospatial data snapshots as GDA2020 (geometry and coordinates) in June 2021. The new solution will replace service Map Packages with a File Geodatabase (FGDB) for each individual dataset, provide legacy support for GDA94 and the option to choose file format and datum.

SLIP web services will remain in WGS84 (equivalent to GDA94) to support web mapping and avoid data misalignments. The geometry of data supplied to SLIP is transformed to WGS84 (equivalent to GDA94) for storing and publishing, however, any coordinates present in data attributes will not be transformed. Users should refer to Data WA to confirm the datum of coordinate attributes in SLIP web services.

A new section on GDA2020 and SLIP is now available in the Data WA Toolkit.

Recommended reading and more information

Please see the ANZLIC guidelines on preparing metadata for GDA2020 and AGRS. This document also provides information about upgrades to the AGRS, recommendations on how to record it in the metadata and several examples covering common use cases. Contact ANZ_MDWG@ga.gov.au for more information and feedback.

For advice on web mapping and the use of WGS84 WM please see the ICSM website and GMIWG Advisory on WGS84 and Web Mapping.

For more information on GDA2020 technical implementation and Landgate’s GDA2020 project please see the GDA2020 page on the Landgate website.

---

The Data WA Team

https://data.wa.gov.au/lets-connect