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WGS84 vs. UTM


SixDogTeam

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Posted

My Magellan 310 displays minutes to two decimal places not three as listed on cache pages, so I have been using the UTM coordinates to find caches. If I mark a location using UTM, how do I translate that into Degrees and decimal minutes to three decimal places? which I will need to do to hide a cache...

 

woo-woo-wuf!!

Posted

Not a good idea. Although you can translate the UTM to Minutes decimal places, since the Magellan is only giving the location to 2 decimal places in Minutes, your coordinates could be off an additional 60 feet in adition to the circle of inaccuracy inherent in all consumer grade GPR's. My guess is that even though you are taking a reading in UTM, you'll still begin with the same lack of precision.

 

You ought to be using a unit that gives the coordinates to 3 decimal places to begin with.

 

On the other hand I could be wrong about this since I don't own a Magellan 310/

 

Alan

Posted

By the way, UTM has nothing to do with WGS84. WGS84 is the Datum while UTM is the position. Degrees and Minutes are also another type of position like UTM, but neither of them have anything to do with WGS84 or any other Datum.

 

MAybe someone else can explain this better thqan I can.

 

Alan

Posted

There is probably a website that will do that for you if you search it out.

 

We have had a prolific cache placer who has a 2 decimal GPS. He did ok. People would give him better coorinates when they found it if they needed it.

Posted

icon_mad.gifHey, Fuzzy, how're ya doin', huh? Havin' lots of fun ridiculing newbies because they don't know as much as you? Yeah that's the ticket. Bet that makes everybody think you're a real BIG MAN, huh?

 

woo-woo-wuf!!

Posted

quote:
Originally posted by Alan2:

Not a good idea. Although you can translate the UTM to Minutes decimal places, since the Magellan is only giving the location to 2 decimal places in Minutes, your coordinates could be off an additional 60 feet in adition to the circle of inaccuracy inherent in all consumer grade GPR's. My guess is that even though you are taking a reading in UTM, you'll still begin with the same lack of precision.


 

This is incorrect. The Magellan 310 limitation is only of the display; it measures the position to the same precision as newer models. You can get the additional precision by looking at the NMEA output.

 

The UTM precision is 1 meter, or about 3 feet. Plug the UTM coordinates into the coordinate translator at Jeeep.com and you'll get DD MM.MMM coordinates with sufficient precision.

Posted

icon_cool.gifThank you so much, Fizzy!!Finally the answer we've been looking for!! I should have guessed it would have to come from another dog. I'm a Siberian(WHite Russian, not Red) Husky. What are you?

 

woo-woo-wuf!!

Posted

UTM might display to whole metres but doesn't necessarily mean that precision is 1 metre.

 

Some might have noticed that trying to enter some specific last digit UTM coords that what one tries to put in is actually changed by the receiver. Basically the receiver is conforming the display compatible with the underlying coordinate system the receiver is actually storing the information in.

 

Cheers, Kerry.

 

I never get lost icon_smile.gif everybody keeps telling me where to go icon_wink.gif

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