For our safari trip to Kenya and Tanzania, I used my iPhone 6 to record GPS tracks of our travels. As keeper of all the photography gear, I had a lot of gadgets, chargers, and cables to pack, and since my iPhone was coming with us anyway, I tried a few experiments to see if I could use it instead of a dedicated GPS. And, with a few very minor caveats, an iPhone in airplane mode makes a fine GPS device.
I used an app called GeoTagPhotos Pro, which has a very simple record interface, and offers very easy export to GPX format, via email or Dropbox. Some of the tracks are a bit messy because sometimes I forgot to leave the phone out and tucked it deep into a bag, but overall it worked quite well enough.
These are the overall land tracks for Kenya, mainland Tanzania, and Zanzibar, combined from a multiple individual tracks for our various outings.
We flew from Nairobi's Wilson Airport to a tiny airstrip near the Masai Mara and back, then from Wilson to Kilimanjaro Airport in Tanzania. After our week or so covering Tanzania, we flew from the Central Serengeti airstrip to Zanzibar.
It turns out that small prop planes don't have enough shielding to block GPS signals to a phone in the main cabin, so I was able to capture tracks for all the small aircraft flights. Unfortunately, that wasn't possible for our flight from Zanzibar to Dar es Salaam, or any of our international flights.