The Intensity/Duration graph allows you to quickly visualise the distribution of all your rides in duration and intensity. The coloured curves are the ISO-loads expressed in Effort Score (ES). The more the activity is at the top right of the graph, the more difficult it was. Conversely, if your activity is at the bottom left of the graph, the easier it was.
This new graph allows you to quickly see what types of rides you do regularly and to optimise your planning, or even avoid possible monotony.