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GDA2020 & WGS84 (Web GIS)

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06-01-2021 05:57 PM
GordonSumerling
Esri Regular Contributor
9 1 5,373

(June 2021)

Many of our Australian clients have now commenced or are contemplating moving their data from the GDA94 datum to Australia's modern datum GDA2020. 

The challenge with this move has been, that there was not a direct transformation between GDA2020 and WGS84. Data had to be moved through GDA94 to publish to WGS84. This has now changed as of January 2021. ICSM have released a new set of transformations. These now enable direct transformations to WGS84 (WebGIS) from GDA2020 and ArcGIS is now adding support as follows:

  • ArcGIS Pro – Version 2.8 – Released May 2021
  • ArcGIS Enterprise – Version 10.9.1 – Late Q4 2021
  • Note: ArcGIS Enterprise 10.9 does NOT have these transformations. Released May 2021

The updated transformations are as follows: 

EPSG NAMETYPE / DESCRIPTION
1150GDA94 to WGS84 (1)Null Transformation to WGS84 ensemble.
Approximation at +/- 3m using assumption that GDA94 is
equivalent to low accuracy WGS84 (ensemble)
9688 – NewGDA94 to WGS 84 (2)[Non-Null] 7 parameter transformation:
Equivalent to 8048 plus (null) 8450
9689 – NewGDA94 to WGS 84 (3)[Non-Null] NTv2 Conformal & Distortion:
Equivalent to 8447 plus (null) 8450
8450 – New
to ArcGIS
GDA2020 to WGS 84 (2)Null Transformation to WGS84 ensemble.
Approximation at +/- 3m using assumption that GDA2020 is
equivalent to low accuracy WGS 84 (ensemble)
9690 –  NewWGS 84 to GDA2020 (3)[Non-Null] 7 parameter transformation:
Equivalent to 8048 plus (null) 1150
9691 – NewWGS 84 to GDA2020 (4)[Non-Null] NTv2 Conformal & Distortion:
Equivalent to 8447 plus (null) 1150

 

To the end user this means that you can now move to GDA2020 and publish your data to Web GIS (WGS84) and also transform the occasional GDA94 dataset  to Web GIS and have it align with your authoritative datasets.

If you need to know more jump over to to our Esri Australia Blog site where this is detailed further. 

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Imagery and Lidar specialist Esri Australia Gotta love that imagery!