This is the Bad Wolf Routes, plugin for Joomla.

It enables you to integrate Google Maps, to your Joomla site. The plugin allows you to enter markers on the map, and link them to present a route.

You will need a Google Maps API key, for your site. (it needs a specific one for the url you will install the script)
For the markers GPS locations, we suggest you use this site http://hobbiton.thisside.net/advmap.html

Also, here is a tool that transforms the coordinates into decimal numbers http://www.cosports.com/tools/gps_coords.htm

Another way to do this is as mentioned here http://www.mmenterprises.co.uk/blog/2007/07/how-to-find-gps-coodinates-from-google.htm

At the bottom, it shows the coordinates at this form by clicking on "Set Marker":

Latitude/Longitude at map center: 46.558860 / 41.484375

Google Maps Desktop Program shows you the Coordinates at degrees, and this plugin requires decimal numbers.

Once you have set your markers, you can make a polyline, linking the markers in any order you want, presenting a route or itinerary.

Please note, that this plugin is provided "as is", with no support from our part. It is an in-house modification to a Joomla plugin, powering the site Bad Wolf Routes.

The plugin is at Beta phase, even its installation has quirks. You will need some technical knowledge to make it work. We cannot help you in this. It is not suggested that you install this plugin to an active website, as it may conflict with other scripts. Please try it on a test installation of Joomla.

The plugin is released for free, by respect and tribute to the global Open Source Projects out there, that provide anyone with powerful tools to create, communicate, entertain and inform.