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A Bit of Latitude Crept into the Datum

Geostationary Satellites

Australia and New Zealand Datums

Thanks to our active tectonic plates, the datums of both countries are becoming rather outdatumed. For example, Australia has had about 1.5m of land mass shift from its 1994 position relative to the earth’s surface.

NZ has implemented its new datum NZGD2000 and projection NZTM2000.

On 1 January 2017, Australia’s first step in a multi-year process is heralded by implementation of GDA2020.  The second stage is in 2023.

In Switzerland we are changing too from CH1903 to LV1995. So the reference system in Switzerland we are using is more than 100 years old and it takes more than 20 years from the new measurement to changing to the new reference system. — from Gian-Reto at OCAD Inc.


The latest Australian official advice re the datum changes is on the ANZLIC Committee on Surveying and Mapping website for GDA2020

Also worth reading is this presentation from RMIT.

NZ Map Grid

For New Zealand datum change see the NZ Land Information website for NZGD2000

OCAD Co-ordinate Systems

The OCAD co-ordinate system combines datum with the country map grid. e.g. GDA94 Zone 55.

OCAD Inc already has in place the new NZ co-ordinate system based on NZGD2000.

When the Australian parameters are available, they will do the same for GDA2020.

Transforming from Old to New

Very simple. Under the Map | Transform menu you select Change Co-ordinate System, then select the new co-ordinate system and it is done.

Geostationary satellite image source Wikipedia

Not entirely unrelated

GPS registers most accurate signal yet. NASA aerospace analysts recently calculated the signal-in-space accuracy of GPS to 38 centimeters. Good news for farmers and auto-drive car developers. Read more and also click the image at top of that reading for GPS info you might not be aware of.




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