Latitude/Longitude referencing

Willem

OziExplorer can show your position in all of the above formats. By Hema, do you mean their maps or Hema Navigator?

BTW, I have an issue when using Garmin XT. It only likes the format in WGS84 and Deg & Min. When I want to put in a location that is not on the map, I sometimes have to convert my co-ordinate. For that I either show the position in OziExplorer and then change it to show it in Garmin XT format or use a spreadsheet to convert. However, the spreadsheet does not convert from one Datum to another.

Why do they all use diffferent formats? Well slowly, I think the WGS84 Deg Min is becoming the standard. This is format that your GPS receives from the satelites.

Laurie

Willem

If it helps any -

The main Datums used in Australia are AGD66, GDA94,WGS84.

Most older maps will use AGD66 while newer maps (about 1999 onwards) use GDA94.

The difference between AGD66 and GDA94 is about 204meters at Adelaide. The same point on AGD66 is about 200 metres north east on a GDA94 map.

GDA94 and WGS84 are very close (only centimetres) so can be taken as the same.

The GPS and Map have to use the same datum to get accuracy. One of the problems of some mosiac maps is that you can get different datums on different maps. Latest versions of mosiacs usually have this corrected.

The best default to use is WGS84 (which is standard on most GPS) and GDA94 maps which most new ones are.

Doesn't solve your problem but may help explain what the problem is.

Generally find when driving that 200 yards is accurate enough to find correct turnoff. (but have to be wary where mutiple roads are very close together. But after choosing one and checking down the track usually confirms whether it was right or wrong.

Alan

If you 'right' click on the Lat/Long info (top/left) on the map window in OziExplorer- it will give you the options...
Cheers

In Ozi, just right-click up the top-left where it shows the coordinates, and you can choose between DMS, DM.M and DD.

FYI - your points in Hema and Google Earth are only about 25m apart, but your Ozi point is about 130m out.
That represents about 4 pixels on a Natmap 1:250k map, so that's pretty good if you're using a large scale map.

I often wonder why people give the same answer 2-4 times in a thread,Are they in such a hurry to help (its understandable) or just read the initial question and just reply without looking at the numerous replies beforehand...

or do i look at it like this ,if there is 3-4 of the same answer in a thread i should deem it to be the right answer...

or do i need to ask the audience.


cheers guys

Hi Willem,
You can also change the google trig point reference read out to read to same as OziExplorer by opening the 'Tools' section on the Google Earth toothbar, selecting 'Options' then in the 'Show Lat/Long' window select what readout out you want. It gives you all the readouts including UTM. Cheers.