Write an Android application to load and display a jp2 map file for Total OFF-LINE Use

I require an app that can use the internet to get data and purchase additional maps, but when displaying a map and using the GPS to show the user position on the map it is totally off-line. The App will have four basic functions: 1.. Download a selected zipped map file from list of filenames that refer to a unique URL unzip the files (.jp2 and .xml) and store it on the device for future use offline. - A default map will be included in the App. A total of 12 URL addresses will need to be listed. A sample of the downloaded file can be provided - approx 36Mb 2.. Allow the user to select a map to display and zoom in / out/ scroll around the map. 3. Allow the user to turn on the device GPS which will check if the the map at the users current position has been purchased, and if not prompt the required map to be loaded (provided internet connection is available) and displayed based the users current GPS position and display the current position on the map as a overlay. if the user does not have the required map download for their current position display a message to download the required map after purchasing it thru in app billing. 4. Allow the user to use in app billing to purchase (enable) the additional maps Use of the App will be 100% offline except for the initial download and purchase of the map files. Main screen should show a background picture with the options: "Display Maps" "Purchase Maps" When on the display maps screen the user should only be able to see maps they have purchased. The purchase screen can either show a list of maps to purchase or a clickable map. Map screen should have a pop up menu to turn GPS On/Off All Android Studio code is to be provided on completion prior to final payment. Once completed a IOS version for Iphone and Ipad will be required. NDA required.