Many other DAWs have added a "session overview" element to the GUIs in recent versions, allowing you to see the entire session at some level of detail, regardless of what part of it is visible in the main editor/arrange window. Ardour 3.0 now has such a view, thanks to the efforts of Carl Hetherington, and it can be used to both get an idea of which part of the session you're currently working on, to scroll (horizontally and vertically) around the session, and to zoom in and out. Here's a sample view - the overview itself is in a resizable pane and so you can hide it away if you don't want to see it.
