After viewing a trail from the map view of the trail directory, the map returns to the same zoom extent (as well as search filters). As an example, today I had loaded the trail map to look at trails for Otago / Southland as I will be down that way in a couple of months. I clicked on a trail to see more detail and when I went back out I was back to the original map of the country, rather than the zoom extent on the map I was a previously, to continue looking at trails in that area.