Gps Datums & Marks

[kingpig]

Mondo started an interesting thread on GPS marks.

I had not realised that GPS systems work on different standards and that a mark with a unit using an Aus66 datum will be a different location on a unit using a WGS system.

In short if your mate has a unit that is using a different datum than yours the same fishing spot will have different cooridanates.

I am interesed if anyone can shed some more light on this issue?

Cheers

Kingpig

[Lightweight]

In short if your mate has a unit that is using a different datum than yours the same fishing spot will have different cooridanates.

Yep. That will be the case.

If you are comparing your co-ords to a map, then the map will specify the Datum that you will need to have set on your GPS unit.

If you have recently modern maps, then you will find that they are most probably WGS84.

LW

[netic]

The difference between AUS66 and WGS84 is about 250 metres.

Which means that if you enter in AUS66 co-ordinates into your WGS 84 gps it will put you around 250 metres of the mark.

Here is a way to transfer marks between the two.

If you use GDA (GDA94 or WGS84), you will need to modify the readings for use with your GPS by either using AGD (AUS66) or by subtracting 5.6' from the given latitudes and adding 4.2' to the given longitudes (approximately in Sydney and NSW).

You can also download this software which will convert them for you.

Link to software

Hope that helps

[Dorado 2]

Hi guys

I was once told by a very knowledgable person that if you had marks with different datums all you had to do is convert your existing wgs84 marks to aus66 by changing the datum settings on your gps when you have done that enter the new waypoints which in this case are aus66, once all in change the settings back to WGS84 on the gps again and all will be converted for you

Cheers