Going for some trekking in the far Himalaya, I'm planning to use my Android phone and My Tracks application as a Handheld GPS Navigator. This will allow me to keep track of the complete journey maps and statistics.
My Tracks is a very neat and simple Google application that keeps track of your complete journey. It is using your phone's GPS and Google Maps to draw the real time map of the journey. One main drawback of using Google Maps for this purpose is that it is using the data connection to retrieve the maps data from Google servers when needed. As 3G connection may not be available when I'm lost in the Himalayan peaks, the whole chain may be broken ...
Hopefully, even if Google Maps for Android doesn't officially include a caching feature to use maps offline, latest version includes the "Ok maps" easter egg that allows you to save current map for offline use. So it then becomes possible to preload your journey maps to be able to use My Tracks as a offline Navigator.
This article explains how to use hidden Google Maps caching feature to save offline maps and to use them with My Tracks when 3G data connection is not available. Your Android phone will then become a complete Handheld GPS Navigator.
It has been tested on a Nexus 4 running Jelly Bean 4.3 and Maps 7.1. It should work on any Android device running latest version of Google Maps.
1. Preload the Maps in Google Maps
Thanks to an easter egg provided by Google, it is possible to cache your maps in Google Maps to use them offline.
You just need to display the map you want to cache, making sure that the displayed region is not too wide. A region of 20km x 20 km should be ok.
Then, type ok maps in the location field.
As soon as you validate, you'll see a preload progression message. This may take some time to reach 100%, depending on the selected region and the speed of your data connection.
A message will inform you that the map has been cached.
You should repeat this step as many time as needed to record all the maps you need into your phone's cache.
2. Navigate Offline with My Tracks
You can now cut your data connexion and use My Tracks.
You'll then be able to navigate using the offline maps.
You may notice that the map is not as detailed as when you are online, but it is more than enough to be fully usable.
You'll also realize that a nice side aspect of this offline navigation is that your phone battery will last much, much longer !
This can be important when you are lost in the mountains without electricity to recharge your phone.
Have a good trek :-)