Australian Height Datum

Australian Height Datum
Example of a surveying expedition in the 20th Century similar to those undertaken to complete the Australian Height Datum.
General information
Unit system	metric
Unit of	height
Date Established	July 1971
Reference Network	The Australian National Levelling Network

The Australian Height Datum was introduced in 1971 as the official vertical datum for Australia, and thereby serves as the benchmark to which all height measurements are referred. The Australian Height Datum is an amalgamation of decades of spirit levelling work conducted by numerous state and territory authorities across the country, and was corrected to align with the mean sea level observations of thirty tide gauges positioned around the entire coastline.^[1][2] While it remains the published vertical datum for all surveying and engineering operations performed throughout Australia, newer technologies have uncovered numerous deficiencies, offsets and distortions within the Australian Height Datum, leading to discussions about defining a new Australian vertical datum.^[2][3]