Although this is a subjective criterium, some parts of the section will be pleasant riding, like through forests or interesting places (points of interests). In the section approach you are asked to fill in the amount of KMs which you consider as pleasant riding because there is always something interesting to see.
Pictures illustrating of cycling made attractive at the start of the F3 in Leuven (BE), and along Winchesters landmarks (UK) and Cycling "Through The Water" (Bokrijk, Belgium).
A specific tool for assessing Attractivity is also being built by Flanders' Bike Valley.