MAPPING TRAPS

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I am new to prospecting but have had years of experience working in the bush. Today I came across a problem while looking up areas to detect. I had found a likely area and when I went to locate it on the maps I was using, I kept coming up with different grid references. Couldn't figure out what the hell was going on so rang a mate I used to work with in the Forests Commission.
Turned out it wasn't me at all, the problem was the 1: 50000 map book I was using is a lot more recent than the 1:25000 Topographic map that I have had for years.
Apparently they changed the Cadastrals (or something like that) a few years ago now the old map shows a grid reference that is about 2oo yards out BUGGER.
No harm done in this case but it looks like I will have to stop using the old maps for grid referencing work, I have just dug them up out of the old shed too.
Has anyone else fallen for this trap?
 
Thanks Westaus, those references will be great and really help me understand the new mapping system.
Unfortunately I left work a couple of years ago, just before the changes were made
 
Bugga there's a lot to learn . I think I'm to old for that stuff lol.

Dibs

But shit what a gr8 page
 
Yeah guys if you're using maps older than 1994, the grid locations when compared against a modern GPS unit will be out by about that. ??
The introduction of the MGA94 grid from AMG66 moved the same location about 164m (or something pretty close) to the NE in coordinates, in WA at least. Probably similar elsewhere.
That's not a huge amount in the big picture of things but if you need accuracy then obviously it's a hell of a lot.
And just to make things 'better' there's going to be another grid change in the next few years. But I think this one will only move by a few metres. I'm sure it all makes life easier for someone....!
 
Zengeo said:
Yeah guys if you're using maps older than 1994, the grid locations when compared against a modern GPS unit will be out by about that. ??
The introduction of the MGA94 grid from AMG66 moved the same location about 164m (or something pretty close) to the NE in coordinates, in WA at least. Probably similar elsewhere.
That's not a huge amount in the big picture of things but if you need accuracy then obviously it's a hell of a lot.
And just to make things 'better' there's going to be another grid change in the next few years. But I think this one will only move by a few metres. I'm sure it all makes life easier for someone....!

Saw a group of USMC mortar team almost take out their forward observors because of this very problem when they came to visit our range in the NT. Not good when they were using HE rounds. 8)

Cheers

Doug
 
The new Australian Datum (GDA2020) is only shifting by 1.8m to the NE from the older one (GDA94), so no big deal for most of us using GDA94.
Many organisations are now implementing their mapping based on GDA2020.
 

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