I have been playing with an offline gps for my Iphone and Mini Ipad, both have cellular and wi-fi connection capabilities.
I have downloaded Sygic: GPS Navigation, Offline Maps. You can download a free version and if needed you get the paid version. I was lucky and bought the world map for $40.00 with lifetime free map updates. Since I made my purchase, the special came up again 2 or 3 months later.
A Youtube Video for a quick rundown.
I am very impressed with Sygic. It seems to be very accurate with the internet data turned off. Once you learn to navigate around the menus it is very easy. Once the initial route has been shown on the screen, you can add lots of waypoints just by touching screen and dragging waypoint onto another road. It is easy to zoom in on a particular part of the route and change the way you go by adding a waypoint.
Try the free version and wait for the worldmaps to come on special. One never knows if you will travel overseas one day.
Wikicamps GPS coordinates are very easy to enter into Sygic.
My Ipad has the sim card slot which has GPS receiver capabilities.
Below is a couple of screenshots.
You can touch the optional route to swap routes.
Most GPS’s can’t do this. (mine doesn’t anyway).
The biggest problem I have found with my GPS is if you are not familiar with the area you must just follow it to your destination. It will get you there but you have no input. With Sygic you can zoom in anywhere along your route and touch the route and drag it to a new destination. This requires a little bit of practice to get the hang of it.
I have used it extensively on areas I know, trying to get used to it and find it very accurate. I have entered GPS coordinates and this works easily and supports 3 different formats. You can set your option or just select which format when entering coordinates.
I use Sygic on my mini Ipad with the charger plugged in as it does drain the battery over a few hours.