Tag Archives: Transformations

Publishing to ArcGIS Enterprise 10.9.0 and earlier from ArcGIS Pro 2.8.3 and earlier using Spatial References in Australia

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. Versions of ArcGIS Pro 2.2 and greater now support GDA2020, the associated projections, and transformations between it and GDA94.

ArcGIS users who are required to continue working with data in GDA94 format may encounter problems sharing web maps from ArcGIS Pro 2.8.3 and earlier to ArcGIS Enterprise up to and including version 10.9.0.

Attempts to share a web map fail with this message – ERROR 001369: Failed to create the service

Log context messages contain the following information –

  • ArcGIS Pro – “Default Map name is: Incompatible Map.”
  • ArcMap – “Default Map name is: Layers.”

ArcGIS Pro 2.8.0 introduced a new set of transformations for transforming between GDA94 and WGS84

When a new map is created in ArcGIS Pro 2.8.0 and above with at least one layer in GDA94 based coordinate system, the default transformation is set to “GDA 1994 to WGS 1984 2″ as below.

This new transformation – “GDA 1994 to WGS 1984 2″ – is only available with ArcGIS Enterprise 10.9.1 and greater.

The workaround is to change the map’s coordinate transformation settings by opening map properties and changing the transformation to “GDA 1994 to WGS 1984”.

More information about Spatial References, Projections and Transformations.

Understanding Spatial References in Australia

GDA94, GDA2020 and WGS84; The projection dilemma

GDA2020, ArcGIS Online and the Web Mercator Dilemma

GDA2020, ArcGIS Online and the Web Mercator Dilemma

In ArcGIS Online Map Viewer, all layers in a web map inherit the coordinate system of the basemap. WGS 1984 Web Mercator (auxiliary sphere) is the spatial reference of basemap services in the default Esri basemap gallery, meaning this is the default web GIS coordinate system. Layers also have their own spatial reference and transformations defined at a service level. When you add layers to the Web Map Viewer, an on-the-fly reprojection is performed to align your data with the coordinate system of the basemap.

When publishing data to web GIS you need to consider what spatial reference will be used to store the data at a service level, how the publishing process may affect it, as well as what transformations (or lack of) will be applied when the layer is displayed in a web map with a datum.

It is also important to understand GDA2020 and its relationship with web GIS. The de facto WGS84 in web GIS brings some challenges not unique to Australia or ArcGIS. Failing to address these challenges may result in data misalignment.

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Introduction of GDA2020 to ArcGIS and how to install additional transformations

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.

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Understanding Spatial References in Australia

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.

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