Geocaching Australia

When I’m out caching by myself in the car, I usually choose a cache in c:geo, then hit the navigation button to get turn by turn voice instructions to get close to the cache in my car.
I can also do this using the Geocaching.com app for Android.

It has come to my attention that you can’t do this with the Geocaching.com app for iOS, and you can’t do it with GeoSphere either a user of that app has told me.

Is this an iOS platform limitation, or just a lack of functionality in those two iOS apps?

I am interested to know, and if this is a platform limitation on iOS, that is, passing a parameter and then transferring control to another app, it’s probably something people trying to make a purchase decision should be aware of.

Geosphere allows you to get turn by turn directions, either in the IOS maps or in Google Maps, by using Bookmarks. I haven't used this feature myself but a quick test shows it seems to work.

Sounds messy.
Would that be quick and easy to do in the field?

It's easy. You can specify what bookmarks you want shown in each cache listing as default. Bring up the cache listing, scroll down, click "Directions in Maps", and off you go.