1. A method of generating a location based reminder by a navigation system, comprising the following steps of: creating reminder message data which include a reminder message, a primary location, a secondary location defines a Point Of Interest (POI) type, and a validation rule where the primary location is a location associated with the reminder message, a secondary location is a location where a user conducts an activity defined by the reminder message, and the validation rule defines condition for generating the reminder message; comparing a reference location with the primary location where the reference location is a destination that is specified by the user for a route guidance operation of the navigation system; applying the validation rule in the reminder message data to determine whether a relationship between the primary location and the reference location satisfies the condition in the validation rule for generating the reminder message; displaying the reminder message associated with the primary location when the condition defined in the validation rule is satisfied where the display includes one or more candidate secondary locations determined by the navigation system based on the POI type and within a predetermined distance from the reference location; and conducting a route guidance operation to reach a location selected from the one or more candidate secondary locations by the user.