I use Gaia on my iPhone and on my computer - to plan a hike on the computer. Works quite well. I also use Earthmate on my iPhone since I carry an inReach - easier to type on the phone than on the inReach. I've got two programs (I'm trying to decide which one to keep) called PeakFinder and Peakvisor. Pretty cool, download the data for the area you'll be hiking in, and then you can point the phone's camera at a mountain and the program will tell you what its name is. I'm often backpacking in areas I'm unfamiliar with, so they're enjoyable programs to use. And I've got Guthook's program for the Wonderland Trail which I hope to do within the next year.