Important information before you start
Important: Proceed with caution when mixing WGS84 with GDA2020 data unless your basemap projection is GDA94 or your software supports the transformation path WGS84>GDA94>GDA2020. See the overview article for more information on WGS84.
Info: For Mainland Australia there are two (2) grids for transforming data between GDA94 and GDA2020, Conformal (C) (EPSG:8446) and Conformal + Distortion (CD) (EPSG:8447). For the Indian Ocean Territories of Christmas Island and Cocos (Keeling) Islands, there are additional 2D Conformal only transformation grids.
Unless the benefits of adopting another transformation method [EPSG: 8446 or 8048] have been expressly identified, the Conformal + Distortion transformation grid [EPSG: 8447] is the recommended transformation method for spatial data in Western Australia.
Use the Conformal only method to transform data outside the extent of Conformal + Distortion grid.
Depending on your software you may have to install or manually configure transformations.
Important: Be aware of data spanning mainland Australia and outside of the national NTv2 grid extent. Conformal only transformations (e.g EPSG:8048 Seven parameter similarity transformation) should be used for data outside of the national extent.
Summary of SLIP service type and GDA2020 compatibility
The below table is a summary of services and compatibility with GDA2020 as tested with Esri ArcMap (10.6+) and QGIS (3.8+). Two popular GIS software applications used by SLIP customers.
Tip: Esri ArcMap 10.6 and above supports the transformation path WGS84>GDA94>GDA2020 (composite or double-hop) for consuming Esri Map and Feature Services in WGS84 (EPSG:3857). Note aerial imagery is not supported, use GDA94 imageserver instead.
Tip: QGIS is free and Open Source Software (FOSS). Download and install the latest version of QGIS to take advantage of new features.
|
|
GDA2020 compatible? | ||
|---|---|---|---|
|
Service Type and CRS |
Notes |
||
|
Esri MapServer (Vector data) WGS84 (EPSG:3857) |
Info:Yes, 10.6 onwards |
Important: No - use WMS |
Imagery e.g. Locate mosaic does not reproject. See below. QGIS does not support the double-hop transformation |
|
Esri MapServer (Aerial imagery) WGS84 (EPSG:3857) |
Important: No - use ImageServer |
Important: No - use ImageServer |
e.g. Locate (MapServer) |
|
Esri ImageServer GDA94 (EPSG:4283) |
Info: Yes |
Info: Yes |
e.g. Locate (ImageServer) |
| Esri Token FeatureServer |
Info: Yes |
Important: No - use WFS |
QGIS does not support the double-hop transformation |
|
WMS |
Info: Yes |
Info: Yes |
Change layer CRS to GDA94 in QGIS |
|
WFS |
Info: Yes |
Info: Yes |
Change layer CRS to GDA94 in QGIS ArcMap not recommended for WFS |
|
WMTS WGS84 (EPSG:3857) |
Info: Yes |
Important: No |
Esri WMTS does not support GDA94. New GDA94 basemap to be published |
Reference: The following examples use sample Landgate Cadastral data and SLIP Public rest services.