Saving the Australian Height Datum

In an increasingly digitised world, the Australian Height Datum (AHD) celebrates its 50th anniversary this year and remains Australia’s first and only legal vertical datum.

This article is the third in a trilogy helping us celebrate the AHD’s golden jubilee, with a focus on NSW.

The adjustment of the Australian National Levelling Network (ANLN) in May 1971 provided, for the first time, a nationwide network of physical AHD heights. For most spatial professionals, the AHD has been ubiquitous for the entire duration of their careers, being the vertical datum of choice because it was the only one.

In the first two articles (Position issues 113 and 114), we outlined the achievements and longevity of the AHD, noted its shortcomings and looked ahead to a new era of vertical datum determination, culminating in the Australian Vertical Working Surface (AVWS) as an alternative for those who need it.

This article describes the datum maintenance and modernisation efforts undertaken by DCS Spatial Services, a business unit of the NSW Department of Customer Service (DCS), through its ongoing Saving AHD projects. As the AHD is showing its age and slowly deteriorating, these projects aim to not only preserve but improve access to it.

Read more in Spatial Source article.

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