1. A method of operation of a navigation system comprising: receiving user input regarding a navigation route for controlling guidance communication along the navigation route for a system user wherein the user input corresponds to a passive-navigation portion for representing one or more locations of the navigation route not requiring communication of the guidance communication for the system user; generating with a control circuit a user geographic-knowledge model based on the user input regarding the navigation route; calculating a system route based on the user geographic-knowledge model; and communicating the system route for guiding the system user in traversing the system route.
2. The method as claimed in claim 1 further comprising: determining a user history based on the navigation route for representing locations previously visited by the system user; calculating a point density based on the user history for representing concentration of locations previously visited by the system user; and wherein: generating the user geographic-knowledge model includes generating the user geographic-knowledge model based on the point density for estimating a familiarity of the system user for a geographic area.