Positioning of mobile phone on handlebar When using a maps app on a smartphone, I find it distinctly more appealing to position the phone in landscape mode. I'm not entirely clear why, perhaps because the app designers (google maps, say) pay special attention to this orientation.

Does the same hold true for cycling? I'm expecting that portrait mode would be more helpful, to see farther ahead where one is going.

The sturdiest designs for mobile phone handlebar holders are meant for one or the other. Rare are the designs allowing one to rotate. I'm shopping for one, hence the question.
I use osmand for navigation and much prefer the portrait orientation. Can’t really say why since I always have the map aligned northwards, so it’s not about being able to look farther ahead. I guess it’s just because I’m used to it and all apps work in portrait mode but some do not work in landscape mode.

The Topeak Ridecase Mount (+Omni Ridecase silicon straps to attach the phone) I use can easily be turned 180° though. I can highly recommend osmand and the Topeak mount.