LkPatrol replied:

Matt,

You need to use Aus GeoDatum 66 (AGD 66) for 90% of Australian Topographic maps, Although some of the Hema maps use WGS 84, these are far less common.
Hope this is of some help.

Cheers, Les

Member - Topcat replied:

Hi Matt, if you are using OziExplorer to download Auslig map info it automatically corrects the Map Datum info to your GPS if the map datum is not the same. I have mine set on WGS84 & OziExplorer comms datum settings the same & have no problems with any of the Auslig or Hema maps. Cheers.Have Wheels Will Travel

Old Soldier replied:

G'day Matt,

Your datum should always be set to the datum of the map you are using.

This is always shown in the marginal information of the map on Auslig and Defence survey maps.

The old datum was the 66, but more and more Australian maps are being made to the WGS 84 [which is virtually the equivalent of the international GDA94 system]

Are you using paper or electronic maps - and what scale??

A lot of the 1:100,000 is all the old system, but more and more of the 1:25,000 is going across to the WGS84.

Bottom line is check out your map margin for the Datum system in use and then set your GPS accordingly [otherwise you could fall off a cliff :) :) :) ]

Be aware that the datum system can vary on adjoining maps. As you progress from one map to another don't automatically assume the next one will have the same datum system.

Better still - get a compass, sharp pencil and protractor and do it all by hand.

But there again, I'm one of those old fashioned navigators :) :) :)

Enjoy the bush

Dennis

Member - Rohan K replied:

Matt, try here http://www.oziexplorer.com/ select site map from the menu on the LHS, then go the technical section and select the "datums" item.

Life just ain't that serious.
Rohan (Sydney)