Yes this is the coolest mapping app that Ive purchased.
Lets just say your going on a hiking trip, or on vacation to an island in the tropics. If you dont have data access, your iPhone, or iPad navigation is not going to workout too well for you.
This is where DIY Maps GPS comes in handy. You can search for a map from google maps and overlay tiles from other mapping sources. Add in the Millions of Points of Interest worldwide and you have the ultimate offline mapping tool.
After you get use to the interface you will be using DIY Maps GPS to create offline maps for the places you travel most.
Contacted the developer and he promises Nautical maps in an upcoming release. Ohhh baby.
iPhoneSDKPro about DIY Map GPS (App for World Travelers)