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Crag & Route Beta

Area	Location	Sub Location	Crag	Links
VIC Grampians	(General)	(General)	(General)	[ Grampians Guide \| Images ]

Topic Date User

Anyone know how to convert GR to lat/long 18-Jun-2014 At 2:33:07 PM gnarly_rider

Message

>>? There's a calculator on the Geoscience Australia website but it's looking for more digits and/or additional map reference information.

You are correct:

1/. These numbers are an abbreviated version of the full Eastings and Northings (6 and 7 digits respectively, in metres), and

2/. You will also need to know the Projection in which these coordinates have been measured, which will be a function of the year they were provided. The 3 most recent Projections were AGD66, AGD84 and GDA94, the last 2 digits (obviously) representing the year that projection was created (and generally was then used in preference to the previous projections. So if the map/booklet your GR numbers have coem from was circa 1990, most likely the GR values are using AGD84

3/. You will also need to know the UTM zone within these projections: the Grampians in I think in zone 54, whilst Melbourne is on Zone 55.

To flesh out the GR numbers, as an example Halls Gap in AGD84 (Zone 54) has coordinates of approx 634200E 5887400N, which I think would equate to GR 342 874. IE (I am rusty) I think GR numbers represent multiples of hundreds of metres.