As Geocachers we are all familiar with the prefix codes used for identifying travelbugs, geocache hides and waymarks, but how useful are they really?

Geocaching.com seams to over complicate matters when it comes to uniquely identifying trackables and cache listings; Take one of our cache hides:

Jurassic Park (Auckland) GC187B8

As you can see the GC code for this listings is GC187B8, this code is a unique identifying code for this cache listing and when you think about it the 5 digit code (assuming case insensitive and alphanumeric 0-9 A-Z for each position) give a total of 36 x 36 x 36 x 36 x 36 = 60,466,176 possible cache listings. At the time of writing this (March 09) there were 740,643 currently active cache listings worldwide on Geocaching.com, this leaves a healthy 59,725,533 codes available for future geocachers!

To view this cache listing you can use the following URL:

http://www.geocaching.com/seek/cache_details.aspx?wp=GC187B8

Although the link it quite long, it does provide a clear indication as to where the link will end up and the GC code is the same as displayed on the listing page and possibly the actual cache container/log book. As simplistic as the above appears… Groundspeak have other ideas when it comes to identifying items on Geocaching.com

For a start the above means of identifying your cache listing is rarely seen, you are much more likely to see the following:

http://www.geocaching.com/seek/cache_details.aspx?guid=2fc53a87-c65a-4d39-858b-a0e3ad7a5872

The large number at the end or the GUID is an internal number for identifying items on Geocaching.com. GUID is a Globally Unique IDentification number. GUID numbers are used within computing to ensure items have a truly unique means of identification, Global in this sense really does mean worldwide unique. So what does this mean for us? pretty much nothing as far as we can tell, it would be used internally with their database system to control the day to day running and retrieval of listings on their system.

Confusion does not stop here… Groundspeak introduce a third system for item identification:

http://www.geocaching.com/seek/cache_details.aspx?ID=757805

The above will also take you to our cache listing. This smaller ID number is used for many of the navigation menu items on a cache listing and appears almost interchangeable with the longer GUID number.

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