Australia has recently moved towards a new datum, the Geocentric Datum of Australia 2020 (GDA2020), to facilitate a more robust, accurate and capable datum that is more closely aligned with the expectations of a modern, connected Australia.
The introduction of a new datum impacts all areas of the software. Esri support for GDA2020 was progressively added as the datum parameters and associated transformation methods were released. All current releases of ArcGIS Pro (2.2 onward) and ArcGIS Desktop (10.6.1 onward) now support GDA2020, the associated projections, and transformations between it and GDA94.
An additional installation is required to support the NTv2 grid-based transformation methods released for GDA94-GDA2020.
GIS data must accurately represent real-world locations to be useful. To do this, you need a standard framework for defining location – a coordinate system. All spatial data utilises a coordinate system to position itself relative to your map and other data. However, coordinate systems are frameworks. They are models, spheroids, imperfect approximations of the shape of the Earth with all its bumps and curves as it changes with time. When working with spatial data you need to consider how a GIS positions this data against reality using coordinate systems.
By better understanding coordinate systems, you will be able to manage your data in a way that increases the accuracy of your maps and the work that you do with them. This blog is the first in a series taking a closer look at using Australian spatial references in ArcGIS. We will start by looking at geographic coordinate systems, projections, and transformations.