Nad27 With Utm Settings

[Cachengrab]

Well I have my Rino 120 and out to the bush we go.......BUT what works better NAD27 with UTM settings or one of the 30 t0 40 other selections?

hddd-mm.mmm.............hddd-mm.ss.s......with WGS84........... Thanks Happy Caching.

[+FarSideX]

These settings are just the way your GPSr displays the position it calculates you are at. Geocaching.com uses WGS84 hddd mm.mmm so that would be the best to use for that purpose. UTM is a smaller grid but most caches are posted using hddd mm.mmm so that is lost in the conversion. EPE cancels that precision anyways.

[Curious George]

Use WGS 84 for your datum or you won't find too many caches. As far as co-ordinates are concerned it's a matter of prefernce. Caches are posted with DD MM.MMM and UTM positions on the site - it's really a matter of personal preference, but UTMs are usually a little faster to enter

[Cachengrab]

Thanks for the replies I was using WGS 84 as my base along with hddd mm.mmm but I was told by a few others to switch to NAD27.

[+mrcpu]

Thanks for the replies I was using WGS 84 as my base along with hddd mm.mmm but I was told by a few others to switch to NAD27.

A lot of maps in Canada are still in NAD27 and haven't been upgraded to WGS84. As for your choice of unit, if you are going off a map you want to use UTM or MGRS (Military Grid Ref System). MGRS is a bit easier to use against a map because you have less numbers to worry about and since MGRS is just a slightly different way to express a UTM location there is no conversion.

 

My sportrak map displays a primary and secondary coordinate system. I leave the primary in WGS84 DD MM.mmmm and the secondary in WGS84 MGRS.

[+Red90]

As stated, if you are referencing a MAP, you need to read the fine print as to the projection method. SOme are WGS84 some are NAD27. And for topo maps UTM is the best system.

[tlg]

Thanks for the replies I was using WGS 84 as my base along with hddd mm.mmm  but I was told by a few others to switch to NAD27.

A lot of maps in Canada are still in NAD27 and haven't been upgraded to WGS84. As for your choice of unit, if you are going off a map you want to use UTM or MGRS (Military Grid Ref System). MGRS is a bit easier to use against a map because you have less numbers to worry about and since MGRS is just a slightly different way to express a UTM location there is no conversion.

 

My sportrak map displays a primary and secondary coordinate system. I leave the primary in WGS84 DD MM.mmmm and the secondary in WGS84 MGRS.

Actually, most base mapping in Canada has been upgraded to NAD83 now, not NAD27. If you pull coordinates of a NAD83 map and then try to find the actual position on the ground by using NAD27 in your GPSr you'll be off by a couple of hundred meters.

 

It's best to use whatever the cache placer used

 

I changed the 82 to 83, yeesh! And I call myself a professional

Edited November 28, 2003 by tlg

[+DustyJacket]

Plus, if you want to do a multi-cache you need to use the same reference datum and notation style.

 

Since the "standard" for www.geocaching.com is WGS84 and DDD MM.MMM then you should use that for geocaching I would think.

 

Use whatever you like for hiking with a map.

Edited November 27, 2003 by DustyJacket

[+Couparangus]

I'm partially just adding this posting to see if I can post alright with the new discussion group software. The only thing I can add is that it is my understanding that all North American geocaches should be in the WGS84 datum. I do radio propagation studies for work and find myself switching betwixt this one and NAD83 for Canada. Usually they are quite close, but often far enough apart to make finding a cache impossible. I’ve seen a Magellan GPS receiver (I use all Garmin myself) where it actually wasn’t clear which datum was being used. I guess if you went looking for a dozen caches and found zero it might be worth checking out which datum you’re using.

 

Cheers!

Coupar-Angus

[+DustyJacket]

.......I’ve seen a Magellan GPS receiver (I use all Garmin myself) where it actually wasn’t clear which datum was being used.......

It is in the setup menu.

[G.P.S Trackers(Romeo)]

I think the biggest and most important is to verify what datum is being used, for what you are using it for.If you have a map and want to compare co-ords or even calibrate it...Always use the same units as the map. Of course geocaching is hard to mess up because its all the same.wgs84.just be sure not to leave your gps in one datum then try caching with a different datum......its very easy to have inaccuracies t o begin with so make sure the pilot can at least put down the landing gear.

[Dave Lucas]

I use my GPS for Geocaching (NAD 27 & Lat Long) and for military exercises... (WGS 84 & UTM).

 

So long as you enter the data into the GPS in the same format and datum it was given to you, you can then afterwards re-set your unit to speak in the other lanquage... well you can if you use a Magellan 315 :-)

[gm100guy]

If you are not geocaching you need to set your gps to what ever datum the map you are using in the bush. And use utm for your cords as they are easier to plot on a paper map when using a roamer.

 

compass

 

I would recommend this compass as a good one to use for plotting your utm cord on map.

 

If you want to print your own maps you could use this software.

 

Softmap

 

When you go to print a map you can set up the grid lines in what ever datum your wish to use.

 

Softmap also now has a decent gps interface that works with the software.

 

[gm100guy]

I had some time today and looked at my Softmap program.

 

Not all the maps that are on the cd's are in nad83. Some of them are still in nad27 and you can see that right on the map from when then scanned it.

 

On the maps when displayed you can look at the metadata and will tell you if it has been updated to nad83.

 

When I overlaid the nad 83 and nad 27 grids over the map you are about 230 meters difference between the 2 datums.

 

The eastings match but the northings in nad27 are further north then nad83 by about the 230 meters.

 

If you want I can post a picture later to show the 2 grids.

 

When I print my maps I print them in nad83 and set the gps to wgs 84 datum and have no problem plotting my position.