"Beam me up Scotty........."

Submitted: Tuesday, Jan 25, 2005 at 21:58
ThreadID: 19774 Views:1931 Replies:2 FollowUps:1
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"The Co-ordinates are......... ummmm........ hang on........"

Well, I'm a little perplexed to say the least.

When I was a lad in Scouts, Skip made us read maps blindfolded, in the dark, whilst hanging upside down! Oh, we thought he was maybe a little harsh, but now I'm not so sure.......

You see, I have just bought my self a small GPS, and a nice Silva Expedition 54 Sighting Compass.

"Why, Wolfie?" you ask......

Because I like to know stuff I guess! Seriously though, because I believe it's good practice to be able to read maps with compass, and maybe use the GPS as a confirming device.

Okay, all is simple........ NOT.

I downloaded a good little pdf off the net, which explains how to read topographical maps here in Australia, mainly NATMAP.

Sit down Wolfie.............

AGD66 & AGD84
AMG66 & AMG84

Okay, so I read up on it all, and seems to make sense, and how lat & long can be out by 200 metres between AGD & GDA. Whoa....... this all happened when I was sleeping! (No wonder those whales ended up on that beach......).

So, sort of got my head around some of this. Hema maps show lat & long, while Natmap shows primarily eastings & northings......why?

Why is one favoured over the other? Is it because geographical co-ords can be confused pre / post 1984?

What are most of you guys quoting over the radio in convoy...... geo or grid, assuming your maps are using both.

God help the great grand kids when they go out in spaceships............

Lost Wolf........

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Reply By: Bonz (Vic) - Tuesday, Jan 25, 2005 at 22:25

Tuesday, Jan 25, 2005 at 22:25
Wolfie, All is not lost.

Go here , go directly to here , do not pass go do not collect $200.

Then go here and buy a copy of the bestest darned learning thingy one can wave on front of their tired eyes.

WGS84 and GDA94 are the same, but different, AGD66 and WGS84 are abotu 200m out from each other but WGS 84 is almost a universal standard (in Australia). Helps to understand this when you look at a map, (theyre large(ish) paper things with wiggly lines in them that you thought your compass and GPS would decipher) then you can use the GPS to help yoou know where you are. Skip was right Wolfie, a map and a compass cant tell you where you are going only you can do that.

Go, read, learn, grow, develop, and strike out into the wilderness with a new found confidence. Lost Wolf no more, you shall be known as the Datum Wolf
Time is an illusion produced by the passage of history

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AnswerID: 94903

Follow Up By: Lone Wolf - Wednesday, Jan 26, 2005 at 10:13

Wednesday, Jan 26, 2005 at 10:13
Bonz, I saw this book down the road at my local camping shop. I thought it was simply all about GPS, but upon closer inspection, it appears it covers a lot more.

I shall check it out later this week.


FollowupID: 353817

Reply By: Member - Mal (Brisbane) - Thursday, Jan 27, 2005 at 15:11

Thursday, Jan 27, 2005 at 15:11

Maps haven't changed since you were in the Scouts very much at all. Your problem is that you bought a new toy!!!

Every map that you would be using will say what DATUM it is using. You will know if it is in degrees or not.

Set your GPS to that Datum and then set to Degrees Minutes and Seconds, or decimals of degrees or minutes, if the map is in degrees.

Just remember that every time you change maps you need to re-check the Datum.

Hope this helps,

Mal T.
AnswerID: 95149

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