Fantastic Topographical Map app!
If you are looking for a great app for hiking, this is it. It allows you to download maps digitally, and also will let your print them! This allows the app to be used even when you are offline. It just uses the iPhones built in GPS. It has hundreds of thousands of trails built in. If you have an iPad or an Apple Watch, it works great on those as well. I ran into an issue with importing a track, sent it to the developer, and it was fixed in the next release!
macosxfiles about
Topo Maps+, v4.0