Add glyphs/trail example (altitude profile + map)

How can I get hover tool working with line glyph (map plot)? It tells me that there's no point selection.
What's the best way to remove noise from this kind of data? In general, there are a lot of peaks, sequences like `0, 0, 4, 0, 0`, which don't make altitude plot look too good. Using `median_filter()` helped, but I'm not sure if this the right or optimal solution for this problem.