Accurate coordinates to a new cache without real GPS

[polakis]

Accurate coordinated are very critical to any cache, new or existing. I want to ask if there is a way to accurate calculate them in order to post coordinates WITHOUT a real GPS device. For example i just own only my i-phone 3G device. Can i find the correct coordinates for my new cache? If not, what can i do? Thank you for any advice

[+user13371]

The iPhone 3G is a "real" GPS, just not accurate enough for your intended purposes. The iPhone 4 is better but I still wouldn't place a cache with it.

 

What can you do? Buy a more accurate GPS and learn to take averaged coordinates with it. Doesn't even need mapping, paperless caching etc., you can keep your iPhone for that. Look at any of Garmin's eTrex line for something in your price range, they'll all work pretty well for placing caches.

[NordicMan]

If you can find a paper topo map of the area that shows coordinate data and is large enough scale, you "should" be able to figure out fairly accurate coordinates using it.

 

Using Google Maps is tempting, but there are quite a few areas where it's precision is too inaccurate to get decent coordinates.

[+user13371]

Hmm... how available are accurate topo maps of Greece?

[polakis]

Thank you for your replies. I know that iphone has a real GPS receiver but as you say with accuracy of 17-40 meters, is useless for placing a geocache. And yes you have a point for the maps in Cyprus and Greece. I am not sure i can find any reliable ones. In this time of period i do not want to buy any gps device. If i did i would go for an expensive more reliable device of Garmin for example. The thing i wonder is if there is a GPS application for iphone that can help at this point. For Android i know there is one that help you calculate and find the average correct point after a while. As far i have checked all similar apps have the same non accurate accuracy of 17 meters in best case.

[+John Drake]

You could also try some alternative approaches:

 

1. You could borrow a "real" GPS, or get someone who has one to go with you when you place the cache.

 

2. Instead of making your cache a traditional cache, you could make it into a Letterbox Hybrid.

 

Letterboxes are a kind of cache with origins from the time before there were GPS devices. Instead of having coordinates, the letterbox description tells you how to find the cache (e.g., "Go down the path to the first fork, look for a tree stump...", etc.). Often the only equipment needed is a compass (if that). (Stamps are also usually part of the process: If you're interested, look up further information on letterboxing.)

 

Cheers.

[+user13371]

As far i have checked all similar apps have the same non accurate accuracy of 17 meters in best case.

Yes, that's about par for a 3G. The 4 is better and has put me within arm's reach of a cache many times -- but never reports a confidence level of closer than 16 feet.

 

I like John Drake's suggest of borrowing a device. Got any caching buddies?

[+dfx]

there's an app called "perfect mark" which claims to be able to do averaging. i still wouldn't trust it though. even if it does proper averaging, with the extremely low accuracy of the iphone it would take a loooooong time to get a significant improvement in accuracy through averaging, and even then i'd say the result would be questionable at best.

 

and yeah, don't use google earth/maps. it's hit and miss, and it can be spot on, it can be slightly off or it can be waaaay off. you just don't know without checking it with GPS.