I have a question about asking for location service's authorization.
I'm working on app which allows to browse for restaurants in a certain place. I want to allow to users to search by specific address (in this case, the results are restaurants near the address, ordered by distance) or by geolocation (in this case results are restaurants near user's position, ordered by distance). Results can be seen on a map or in a list (in a list one can see more details at a glance, on the contrary in a map to see details of a restaurant one has to tap on a restaurant to show them).
I have a doubt. I think that for a mobile usage could be better by opening the map with the user's position already marked (if location services are enabled). In this way one can look for places near him. My doubt is that I don't want to warn users asking for their positions at startup (as many apps do), especially for users who open the app for the first time and don't know it.
Jakob Nielsen talks about it in this post: http://www.nngroup.com/articles/workflow-expectations/.
To avoid this I designed a screen where one can choose the type of search (textual, by address) or by geolocation. In this way, on tap on geolocated search users are aware on the action they perform and then, ask for authorization for their location will be not a problem. The problem is that is not an immediate usage (there is an extra page) and maybe is a little far away from mobile usage and closer to web usage.
What do you think about it?