Vehicle navigation system with route determination based on a measure of sportiness

A method for determining a measure of sportiness for a route for operation in a navigation system, the method comprising:

• determining location data for a curved road portion of the route from map data retrieved from a map database;
• identifying points of inflection from the location data of the curved road portion;
• identifying a plurality of curved segment as road portions between the points of inflection;
• measuring a linear distance, Llinear, between the points of inflection of the plurality of curved segments;
• for each curved segment, measuring a curve depth, H, by identifying the maximum distance between the line between the points of inflection and any point on the curved segment along a perpendicular to the line between points of inflection;
• for each curved segment, calculating a curved segment degree of curviness=H/Llinear;
• and
• when the curved segment degree of curviness has been calculated for each curved segment, combining the curved segment degrees of curviness for the plurality of curved segments to determine the measure of sportiness of the route.

A navigation system comprising:

• a processing unit;
• an input device;
• a display device;
• a map database containing location data;
• a route generator configured to determine a route between a first and second location, the route generator configured to provide the driver with at least one route;
• a curvy route analyzer configured to analyze the route and determine a measure of curviness for the route by identifying points of inflection in curved portions of the route, measuring a curve depth for curved segments between each pair of points of inflection, and using the curve depth to determine the measure of curviness, the curve route analyzer being configured to determine the curve depth by:
• measuring a linear distance, Llinear, between the points of inflection of one of the curved segments;
• and
• identifying the maximum distance between the line between the points of inflection and any point on the curved segment along a perpendicular to the line between points of inflection.