GPS points

[Confused]

G'day ive resently got myself a boat and im getting out into moreton bay alot had some success getting snapper and slatey, ive come across some gps points online but typing the search into google earth doesnt register and if slightly modified they could be way off. ie a point for the rufus king wreck i got was 27º22 706S 153º27 895E with google earth's format i had to make it read like 27 22' 7.06\"S, 153 27' 8.95\"E if typed in sends u way off the clearly obvious position of the wreck, im worried that all these points are not able to be typed into my GPS and if modified to suit will be way off. Can anyone help!?

[Feral]

OK you will have to do some research into Datums.

Most GPS are in datum WGS84

Most Land Based maps are in datum Australian Geodetic 1966 or 1984 or Australian geocentric 1994.

Most marine maps are sweet, because they are in WGS84, so match your GPS unit. They also have the advantage that 1 minute on the scale equals 1 knot distance.

I have no idea what datum google earth uses.

If you get the datum wrong, the points can be off by several hundred metres.

What I think you are struggling with is that there are various ways of displaying a GPS co-ordinate.

Standard way is 27 deg 22' (minutes) 6\" (seconds)

It can also be displayed as a decimal - 22 deg 22.1'(minutes)

(IE 6\" is 1/10 of a minute, which is .1 on the end of the minutes)

Most GPS points these days will use the decimals as it allows greater resolution. (1/100 instead of 1/60, then a third decimal for even higher resolution, down to about 3m)

[Confused]

Thx Feral ive done some simple calculations and i pretty much landed spot on the rufus king wreck with my GPS points so i feel pretty confident that they all will work, Next step is fishing them all and ill post what i catch.. THX

[Feral]

No worries!

[mackmauler]

the rufus is on the eastern side of the bar depending on the state of the tide, you would want to know the area before fishing that one.

it can be above water on a lowish tide

Post edited by: mackmauler, at: 2007/02/27 22:13