Map reference grid question

Davoe's on the money

Also get hold of this book and have a read - should head you in the right direction:)....
Map Reading Guide Link on this page

Cheers
Greg

The map in question is undoubtably showing UTM or TM projection grid lines in addition to Lat Log and as Davoe has pointed out the numbers are only shown in full in one corner - you have to add the relevant begining and end numbers to get the full number for any one grid line and enter these into OziExplorer. Military Grid Referencing systems also shorten the full UTM coordinates - and as with the shortened numbers along edge of map you will need to take them back to the full number before entering them into OziExplorer - there is no option for entering shortened MGRS numbers into OziExplorer (ie it is not "real" grid system on its own ..it uses shortened UTM/TM coordinates). Also WGS (I assume you mean WGS84) is a datum not a grid reference. You must of course specify the correct datum when calibrating any map for OziExplorer(that requires any sort of accuracy). On the 100K maps the datum and projection used are generally shown near the scale bar at bottom of map. If it says TM (Transverse Mercator) for projection, use UTM (Universal TM) as it will work fine and removes the need for some addition input of information.
Cheers
Greg

Thanks Greg and to all the othere who replied.
Its a brand new map from the chart shop in Fremantle, not a terrorist map :-0
It does say transverse Mercartor, so I guess I follow the advise of using UTM calibration.

Its just that I never done UTM, always used lat/long for calibration as most of my chart work is on marine charts which do not have the metric grid reference lines.

I was thinking a bit like some of you older blokes who always convert metric measurements to the old imperial stuff just because it sounds more familiar :-)

I guess I'll just have to get my head around that Northing and Easting way of map reference and let ozi explorer do the number crunching.

Which brings me to another question, will the downloaded track from my GPS still be accurate? The place in question is Lake Dumbleyung and the track is the one my boat would have done.

Klaus

Klaus
Once the Map is calibrated correctlly (using lat/long or UTM - dont mattter) and assuming GPS configuration in OziExplorer is right for your particular gps it will plot exactly on spot - OziExplorer does the hard work. I generally use Lat/Long as well - easier (less numbers to stuff up), especially if you have complete scan of map - each corner of map has the lat/long shown.

Now if you had purchased that wonderful South West WA 50K Raster CD (from C&M Shop or exploroz) you would not have had any probelms at all (as all maps calibrated and ready to go with OziExplorer)..plus its at 50,000 scale so better detail.

Cheers
Greg

No because it is a 100 thou map it probably uses AGD 1966 The 100 thou map in front of me was done in the early 80s and is accurate from 1975 - the 250 thou maps make a better propasition at least in my area