Seems to me there are two main approaches here, one is the online mode where you are just leverage something like aprs.fi api to get points, and the more useful offline mode where you interface your device with an audio cable and setup vox on the radio for TX, etc. I imagine it should be possible to pull together some libs in the OB1 app to pull this off.
GitHub - pulsely/PulseModemA: "PulseModem A" is an iOS APRS client, that reads and reports APRS location and messages. pulls together a few libs to make that app possible on ios.
Would be cool to use my large 12.9" ipad with the app and have gmrs data with filters on that... but I want OB1 to support tablet screen resolution/scaling first. The app looks goofy on it for now.