Non-uniform weighting factor as route algorithm input

The present invention provides a method of determining a route between two locations in a navigation device by calculating the cost of paths between the two locations using a cost function. The cost function applies different weighting factors for the same type of attribute to line segments when the line segments are located in different areas of a map. As such, when the cost of a path is being assessed, the same type of attribute may be associated with different levels of penalty or bonus in different areas. This means that the route determined is less likely to avoid line segments that have a certain negative attribute in areas where the attribute has a less adverse affect.