We found 2 offline map is working fine for travellers or home delivery business. It's one from most favorite brand in mobile Market is NOKIA(new owner is partner with Audi, BMW, Daimler on 2015) and another one is Map me.
We want to introduce for fist offline map Here (Here.com), you can create user and have own collection for GPS coordinate bookmark, share bookmark between your device.
Go to IOS Store or Play Store and search "Here Map"
Install Here Map
Download Offline Map
Activate Offline Map mode
Note : when you activate offline mode you can't access to other area outside offline map data in your phone.
When you want to access other area outside your download map, please activate online mode, need data or WIFI.
A piece of cake" for using Here map