Around 2011 agile was not a commonly used software development technique, that lead me to investigate and experiment different solutions for commonly used tools in waterfall.
Managing a roadmap from a waterfall to an agile environment was a shift of mentality, forcing a more alive, dynamic and adaptive solution.
The following article was originally written in 2013 and published on Scrum Alliance, but I do not know why it was removed.
You can find it now in LinkedIn Creating an Agile Road Map Using Story Mapping
It is one of my first articles I wrote, but I think there is still much value in it.