GPS Configuration

[LesW]

I am new to the GeoCaching World, but have done alot of GPS navigating finding caves and such in New Brunswick. My questions is how exactly MY GPS should be configured! I have tried several Position formats; Map Datum NAD27, NAD 83, & WGS 84; North Reg as Magnetic but still I am about 12km off the grids that are given in GEOCACHING.COM! I have gone to one of the sites and tested my GPS by a return trip to my start location and it is working properly, but I am still not able to find a cache at this point in time! Please assist me soonest as I am ready, willing and able to begin!!

[+briansnat]

You should be using WGS84. Whether you choose magnetic or true north is up to you, as it shouldn't make a difference as far as finding caches.

Edited December 20, 2006 by briansnat

[+NightPilot]

NAD83 and WGS84 are the same, or at least closer than your GPS can differentiate. They are within a foot or two of each other, so you can use either. 12 km is a long way, and I don't see how that is possible if you really have the correct numbers in the GPS. Recheck and make sure you're putting in the right numbers for the caches. Even if you have NAD27 selected, it's pretty close to the others, and won't put you that far off.

 

Are you sure you're entering the numbers in the correct format? The caches are in dd mm.mmm format, meaning you see degrees, and minutes in decimal format to 3 decimal places. If your GPS is set to accept input in dd.dddddd format, meaning decimal degrees, or 98.5847395 degrees, for example, then you might get the difference you're describing. Some GPSrs also accept dd mm ss format, or degrees, minutes, and seconds, which is different from either of the previous formats. You have to use the correct format, and it's possible to convert between them, but the simple solution is to make sure your GPS is set to accept waypoints in dd mm.mmm format.

Edited December 20, 2006 by NightPilot

[+wesleykey]

Geocaching uses WGS84. I once bought a used GPS that was set on an Asian datum. I found every cache to be about 75 feet off until I discovered the error.

[+TeamTettamanti]

Try this http://www.tettamanti.com/gps.htm

 

Hope that helps!

Edited December 21, 2006 by TeamTettamanti

[+DeRock & The Psychic Cacher]

I recently had the same problem, embarassingly so.

 

While trying to solve a puzzle cache I changed my map datum to another format. I then entered the cache coordinates. Then I went hunting for the cache. I ended up about .5 miles from where the cache was really hidden.

 

When I changed the datum back to WGS84 and went back looking for the cache it showed it in a different place but still not right. So I need to delete the waypoint and enter it again. Then the cache showed up where it was really hidden.

 

So the point of my story is: If you enter a waypoint in the wrong map datum it needs to be deleted and re-entered when you have the right map datum loaded. Otherwise it will never show up right.

 

Deane

AKA: DeRock & the Psychic Cacher - Grattan MI

[+Prime Suspect]

I recently had the same problem, embarassingly so.

 

While trying to solve a puzzle cache I changed my map datum to another format. I then entered the cache coordinates. Then I went hunting for the cache. I ended up about .5 miles from where the cache was really hidden.

 

When I changed the datum back to WGS84 and went back looking for the cache it showed it in a different place but still not right. So I need to delete the waypoint and enter it again. Then the cache showed up where it was really hidden.

 

So the point of my story is: If you enter a waypoint in the wrong map datum it needs to be deleted and re-entered when you have the right map datum loaded. Otherwise it will never show up right.

 

Deane

AKA: DeRock & the Psychic Cacher - Grattan MI

Regardless of what your datum is set to, the GPS internally stores them using WGS84. When you select a different datum, you're just telling the GPS what conversion to use when you enter or display a coordinate. So changing the datum won't alter the internal coordinates already stored in the GPS.

[LesW]

Figured it out on my own, but many thanks to the ones that replied!

The answer for all that did reply is:

 

The dd mm.mmm format..... I had it on hddd.mm.mmm Congratulations to NightPilot for the correct answer!

 

And once again, thanks to all for the assistance. I am sure if I have any other pressing "concerns" these forums will be quick and correct in getting me out there into the bush searching Caches!