Getting location of first Cache accurately placed on map

[Guest CrotalusRex]

I have had quite a bit of trouble getting the location "X" of my first cache placed accurately on the map. It seems that my friend's GPS--a garmin--either gave me the wrong coordinates or I am just a dufus when it comes to figuring out this math thing. I have read everything on the Geocaching page and quite a bit here on the forums but I'm still at a loss to figure this out. I don't think the GPS was off because to begin with--it is new, secondly I set it on the exact location of the cache--open to the sky on top of a 6200 foot mountain--and allowed it to sit there for about 10 min before taking down the coordinates --so I feel that the reading is accurate. Possibly I just did it wrong...it was my first time using a GPS and I suck at math.

I have the origional coordinates in Degrees, Min and Seconds and was wondering if anyone out there could help me figure out how to convert these numbers to whatever format they need to be in so that the map (and whoever ventures out to find my cache) dosen't go off in the wrong direction. Jeremy has tried to convert twice but the icon on the map is still way off to the north hovering in space somewhere. If you want to view the cache and map--it's the Cherokee Spirit cache in North Carolina that was posted on Sunday 4/22. I don't recommend anyone attempting to locate this cache until I have worked out all the bugs...you could end up on a wild goose chase.

Thanks, I welcome any input offered.

[Guest Quinnow]

Please forgive me If I am misunderstanding you, and If I am please also disregard this post.

I am not certain I understand your problem, but if it's due to a wrong reading and I am reading that you are new to GPS. The are you certain that your settings on the gps are correct as far as datum?

 

it should be set for...

wgs84 ( lat/lon hddd* mm.mmm)

The topo maps on the site are not the same format but are close enough I think, but maybe in your case where you placed it I might be wrong. But as long as you are sure you have the right datum set in your gps and that you had a clear reading when you took it at your cache, people will find it.

I only use those topo's to see if I am about to walk into a river or something.

I wish you luck!

 

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Quinn Stone

Rochester, NY.14616

www.Navicache.com

[Guest Robereno]

I don?t have any real advice though I?m in a similar situation. I?m new to the GPS scene and left my first cache last week. Spent a lot of time on site taking my readings, averaged for about 10 minutes on my emap and even took a photo of the GPS on its final setting. The first person seeking the cache found it, but only because I had piled some rocks to indicate the site. He said his GPS located it off by 25 ft.. I know there is room for error with these things but a 25 ft. error under an un-obscured sky doesn?t seem too good.

Mostly, I understand that I?ve got a lot of reading to do before I?m comfortable with the process. Time to do my homework.

 

[This message has been edited by Robereno (edited 24 April 2001).]

[Guest Robereno]

I don?t have any real advice though I?m in a similar situation. I?m new to the GPS scene and left my first cache last week. Spent a lot of time on site taking my readings, averaged for about 10 minutes on my emap and even took a photo of the GPS on its final setting. The first person seeking the cache found it, but only because I had piled some rocks to indicate the site. He said his GPS located it off by 25 ft.. I know there is room for error with these things but a 25 ft. error under an un-obscured sky doesn?t seem too good.

Mostly, I understand that I?ve got a lot of reading to do before I?m comfortable with the process. Time to do my homework.

 

[This message has been edited by Robereno (edited 24 April 2001).]

[Guest jeremy]

25 feet is pretty good. Depending on the time of day satellite locks may not be at its best. There are also other things that may impact your signal.

 

Jeremy

[Guest Quinnow]

Actually 25 feet is great at times. And who is to say that your coordinates were off when it might have been his sat reception was a bit tift on his gps. don't knock 25 feet at all, when you think about it there are many caches that are much farther off than that and people are still finding them. what fun would it be if your gps said 1 foot and you look down to see it sitting there. the search is the name of the game, and you will also see people that locate the same cache that say it was dead on. all depends on where and when.

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Quinn Stone

Rochester, NY.14616

www.Navicache.com

 

[This message has been edited by Quinnow (edited 24 April 2001).]

[Guest Robereno]

This is good to hear however, I?m a bit confused about the technology. A few years ago I was in the Grand Canyon watching some USGS contractors doing some surveying. They were using GPS technology however, at their level, they obviously can?t be off by as much as 25 ft. Something tells me they weren?t using a Garmin Emap

 

Originally posted by Quinnow:

Actually 25 feet is great at times.

[Guest Robereno]

This is good to hear however, I?m a bit confused about the technology. A few years ago I was in the Grand Canyon watching some USGS contractors doing some surveying. They were using GPS technology however, at their level, they obviously can?t be off by as much as 25 ft. Something tells me they weren?t using a Garmin Emap

 

Originally posted by Quinnow:

Actually 25 feet is great at times.

[Guest Moun10Bike]

LOCKQUOTE>quote:

---

Originally posted by Robereno:

A few years ago I was in the Grand Canyon watching some USGS contractors doing some surveying.

---

 

Chances are that they were using surveyor-grade GPSRs, which run into the thousands of dollars, and DGPS (differential GPS) corrections, which would get their accuracy to within centimeters.

 

Boy, I'd sure love to have that accuracy in a handheld (WAAS will help, once it is fully implemented)!

[Guest Quinnow]

CrotalusRex,

 

I sent you an e-mail in reply to your top posted problem, but in the case you did not get it here is the answer to it now that I understand it a bit better from your e-mail to me this morning...

 

the geocache site uses the

convention Deg/MIN.MMM and not Deg/MIN SEC, so make sure you leave your GPS in WGS-84 (that's the datum the site uses)

and Deg/MIN.MMM... This means that minutes are displayed

in decimal form like 34.567' and NOT 34' 34.02" (the

equivalent)... (Multiply the .MMM by 60 to get seconds)...

 

and about the map which is in NAD-27... To get the GPS coordinates to agree with the

mapping, you have to set your GPS to NAD-27... This will change the numbers

you see and then they should agree with the map. but be sure not to report those numbers to the site when you place your caches as they want WGS-84

numbers in the DEG/MIN.MMM format.

I hope this helps you and good luck!

 

 

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Quinn Stone

Rochester, NY.14616

www.Navicache.com