Map display for a navigation system

1. A method for displaying map information on a portable computing device, comprising:

when the portable computing device is approaching a location at which maneuvering guidance is to be provided for following a route, presenting a sequence of alternating images on a display screen of the portable computing device,

wherein one of the alternating images is presented on the display screen at a time,

wherein the alternating images include a first image and a second image,

wherein the first image is either an overhead view map image or one of a perspective view map image and a stylized image of an upcoming maneuver,

wherein if the first image is the overhead view map image, the second image is one of the perspective view map image and the stylized image of the upcoming maneuver, and

wherein if the first image is one of the perspective view map image and the stylized image of the upcoming maneuver, the second image is the overhead view map image.

2. The method of claim 1 wherein each of the first and second images occupies the entire display screen of the portable computing device.

3. The method of claim 1 wherein the overhead view map image includes an indicator mark superimposed thereon at a location corresponding to a current position of the portable computing device.

4. The method of claim 1 wherein the overhead view map image includes an indication showing the route to be followed at an upcoming location at which maneuvering guidance is to be provided.

5. The method of claim 1 wherein the perspective view map image includes an indicator mark superimposed thereon at a location corresponding to a current position of the portable computing device.

6. The method of claim 1 wherein the perspective view map image includes an indication showing the route to be followed at an upcoming location at which maneuvering guidance is to be provided.

7. The method of claim 1 wherein the stylized image of the upcoming maneuver is a 2D image.

8. The method of claim 1 wherein the stylized image of the upcoming maneuver is a 3D image.

9. A system for displaying map information on a portable computing device, comprising:

a map database that contains data representing a geographic area that includes a road network;

a positioning system that determines a location of the portable computing device in the geographic area; and

a map display application that accesses the data in the map database to generate a map image around the location of the portable computing device, wherein the map display application presents a sequence of alternating images on a display screen of the portable computing device when the portable computing device is approaching a location at which maneuvering guidance is to be provided for following a route, wherein the alternating images include an overhead view map image and one of a perspective view map image and a stylized image of an upcoming maneuver, and wherein one of the alternating images is presented at a time.

10. The system of claim 9 wherein the portable computing device is removably mounted in a vehicle.

11. The system of claim 9 further comprising a route calculation application that calculates the route from an origin to a destination prior to the map display application presenting the sequence of alternating images.

12. The system of claim 9 wherein the positioning system is a GPS unit associated with the portable computing device.

13. The system of claim 9 wherein the map display application selects 2D data from the map database that represents portions of the road network along the route and transposes the 2D data for rendering the perspective view map image.

14. A system for displaying map information on a portable computing device, comprising in combination:

a processor;

data storage; and

machine language instructions stored in the data storage executable by the processor to:

present a sequence of alternating images on a display screen of the portable computing device when the portable computing device is approaching a location at which maneuvering guidance is to be provided for following a route, wherein the alternating images include an overhead view map image and one of a perspective view map image and a stylized image of an upcoming maneuver, and wherein one of the alternating images is presented at a time.

15. The system of claim 14 further comprising machine language instructions to present the overhead view map image on the display screen of the portable computing device when the portable computing device is following the route but not approaching a next location at which maneuvering guidance is to be provided for following the route.

16. The system of claim 14 wherein each of the alternating images is presented for a time period having a range of one to five seconds.