By guest blogger Marie Fiore, park ranger at Riverbend Park, Palm Beach County, Florida, USA.

I am a park ranger living and working in South Florida. One afternoon a few years ago, near closing time I found a vehicle blocking my exit at the employees-only gate. I was not happy to say the least as I have a number of gates that need to be secured for the night. So, off I went looking for the owner of the vehicle. It turned out there were three of them. Again I was less than pleased seeing them off the trail doing who-knows-what to my park.

The compass shows on the iphone screen, to show me which way to the cache

As I approached them I could see the look of horror in their eyes and their faces drain of color as the big bad ranger got closer. I demanded to know what they were doing and why, AND said they had better have a good reason for blocking me in my own park. I was told simply, Geocaching. WHAT!?!

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Geocaching (pronounced geo-cashing) is a worldwide game of hiding and seeking treasure. A geocacher can place a geocache in the world, pinpoint its location using GPS technology and then share the geocache's existence and location online. Anyone with a GPS device can then try to locate the geocache. Well after they explained it to me, I threw them in my golfcart and off we went to find the other caches in the park. I must admit I had a blast with my three new friends. Who knew? I joined Geocaching.com the next day (the membership is free) and although I found it very interesting I could not afford a GPS unit and just about forgot all about it. Jump ahead 2 years. I had just gotten a new iPhone and was roaming around in the app store. Apps are little programs that you can download and run on your iPhone. When I saw a new app for Geocaching by Groundspeak, the company that runs geocaching.com, I hit the "buy" button before my brain stopped me and out the door I went!

This is what I left in one cache

So how does geocaching work? A geocacher will place a waterproof container containing a log book and trade items then record the cache's coordinates. These coordinates, along with other details of the location, are posted on a website such as Geocaching.com, which is the biggest. Other geocachers download the coordinates and then go looking for the cache using a GPS receiver, or in my case an iPhone. The finding geocachers record their exploits in the logbook and online. Geocachers are free to take objects from the cache in exchange for leaving something, so there is treasure for the next person to find. Geocaches are currently placed in over 100 countries around the world and there are over 890,000 active geocaches. So there's probably one near you!

This is what I found in one geocache

The iPhone application is amazing. Simply amazing.

When I opened the app the first thing I saw was the home page where you can search for nearby caches, caches by address or postal code or by the geocaching code number. You could also look for trackables AND add pocket queries.

So being a first time cacher I clicked on the tab "Find nearby caches". There the list gave me all the information I needed to get started. The name of the cache, size, code number, and distance from my location. Even better it has a tab to see all the caches on a map with three choices, Topo, street, or satellite! I chose satellite. WHOA! Green dots everywhere! I zoomed in on the blue pulsing dot (ME) and found two cache sites less than two miles from my house. By this time it kinda felt like Christmas and Easter on the same day. To be honest it took me for ever to find the first one and I never found the other one, but I had fun. Being I had to work that day I found several other cache sites in the Park I worked at and used the very handy tab "Save for offline use" to add caches to find later.

After choosing a cache to find you are then given all the info to help you complete your search. Again being a newbie, I used the description and recent logs tabs and when I was really stuck I used the hint tab.
Now about the compass: it is very accurate! There were a few times when I got frustrated with it as it was giving me wacky (20 ft. West, no 30 ft. East, no no no, 3 ft. South!!) readings, but after talking with a geofriend I found out that even the best GPS devices do the same thing and that all I had to do was put the phone down and let the satellite "catch up" , also I had NO problems with the compass when I was deep in the woods with tons of cover. I even used the waypoint dohicky to help me find a two-part cache. And I also like that there is even a tab to record a field note. You have instant gratification by letting others know that you did or did not find a cache, leave a message and post it to the Geocaching website right there in the field! You even have the option to search for basic or advanced caches and the app will filter out the caches you have found.

Local cache information is shown with dots representing nearby caches

All in all, I can say, this is one of my favorite apps. I have found 43 caches, one travel bug and a geocoin. So far the only thing I can think of that the app does not have is a tab to record that you either found or dropped off a geocoin or travel bug, but I'm sure that will come in due time. Until then happy caching!

Follow Marie on Twitter: @rangergirl141