Data-driven decisions

Systems, trust and GDA2020

Feb 04, 2019

The value of spatial systems, data and analysis is based on the ability to trust the results they provide to support decision making.

Maintaining the trust depends on ensuring data is well maintained and that changes to inputs are understood and managed to mitigate impacts.

Early in my career I maintained a system that provided property searches to solicitors. Properties were checked against past planning applications, constraints and restrictions using GIS.

Every result had to be cross-checked manually against index cards or planning applications on microfiche. There was no initial trust in the system. Over time, as the accuracy of the results was proven, trust was gained and eventually the checks removed.

The value of the system depended on the quality and accuracy of the data.


Maintaining trust in the system involved ensuring the data was well maintained. As changes were made to the underlying base data, business data was carefully updated to ensure accuracy of results, to maintain the trust and value in the system.

Today, organisations typically have regular data flows from and to other agencies, as well as integration with both internal and external systems. Decisions are made based on precision and accuracy of not only internal datasets, but also data and services provided by third parties.

This is why the shift to Australia’s new geographic datum, GDA2020, is so important. With Australia’s tectonic plate moving 70mm on average per year, physical locations based on GDA94 will be incorrect by up to 1.8m next year when compared with GPS data.

As Land Agencies and others start to implement GDA2020, organisations will start to see data available in the new datum. It will be visualised and analysed alongside existing data and will make its way into our systems.

In some cases it may not be clear if data is in GDA2020 or GDA94 and there is the possibility of incorrect results.

Carefully considering the impacts of GDA2020 is important for organisations to maintain trust in their systems and the decision-making based on the data.

From the outset, Esri Australia has been heavily involved in ensuring that GDA2020 is correctly implemented within the ArcGIS platform. More recently we have been assisting organisations to understand the impacts of GDA2020 and develop strategies for migrating to the new datum.

My advice is start planning now, to ensure that you understand how you will implement GDA2020 in your organisation. 

For more information on preparing your GDA2020 data migration strategy, book a free one-hour phone consultation  or call 1800 870 750.
About the author

Martyn Sutcliffe

Senior Consultant

Esri Australia, Brisbane