Method and apparatus for drawing a map for a navigation system

Claim 2

A map drawing method in which a map showing a present vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the method comprising the steps of: determining whether a presently-traveled road is displayed on the map; generating an image of the presently-traveled road if the presently-traveled road is not already displayed on the map; and displaying the image of the presently-traveled road by superimposing the generated image of the presently-traveled road on the displayed map that did not otherwise display the presently-traveled road.

Claim 3

A map drawing method according to claim 1, further comprising storing map data including at least road data, wherein the stored map data includes a figure attribute.

Claim 4

A map drawing method according to claim 1, wherein the step of determining includes determining whether the presently-traveled road is displayed according to whether the vehicle position is on a presently displayed road or whether the vehicle position is within a predetermined distance of a presently displayed road taking into consideration a vehicle position error.

Claim 5

A map drawing method according to claim 3, wherein the step of determining includes determining according to whether the vehicle position is on a road expressed by figure data.

Claim 6

A map drawing method according to claim 1, wherein if the presently-traveled road branches before reaching a road displayed on the map, the branch roads are displayed.

Claim 7

A map drawing method according to claim 1, wherein the step of generating an image includes accessing a map buffer and further includes the steps of: writing data of a second map containing the presently-traveled road into the map buffer; and generating the image of the presently-traveled road from the data written into the map buffer.

Claim 8

A map drawing method according to claim 6, wherein if a scale of the di splayed map is 1/n while the scale of the second map is 1/m where m<n, the image of the presently-traveled road is displayed at a scale of m/n.

Claim 9

A map drawing method according to claim 7, wherein the image of the presently-traveled road is adjusted if an amount of the data exceeds a predetermined value.

Claim 10

A map drawing method according to claim 1, wherein the step of generating an image includes accessing a memory and includes the steps of: obtaining data defining a road passing the vehicle position from road layer data, and storing the obtained data in the memory; and generating the image of the presently-traveled road from the stored data.

Claim 11

A map drawing method according to claim 1, wherein the step of determining occurs upon selecting a change of a scale of the displayed map.

Claim 12

A map drawing method in which a map showing a vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the method comprising the steps of: determining whether a presently-traveled road is displayed according to whether the vehicle position is on a presently displayed road or whether the vehicle position is within a predetermined distance of a presently displayed road; generating an image of the presently-traveled road using data pertaining to the presently-traveled road if the presently-traveled road is not already displayed on the map; and displaying the image of the presently-traveled road on the display screen by superimposing the image of the presently-traveled road on the displayed map that did not otherwise display the presently-traveled road.

Claim 13

A map drawing method in which a map showing a vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the method comprising the steps of: determining whether a presently-traveled road is displayed according to whether the vehicle position is on a presently displayed road or whether the vehicle position is within a predetermined distance of a presently displayed road; generating an image of the presently-traveled road using data pertaining to the presently-traveled road if the presently-traveled road is not already displayed on the map; and displaying the image of the presently-traveled road on the display screen by superimposing the image of the presently-traveled road on the displayed map that did not otherwise display the presently-traveled road.

Claim 14

A map drawing method according to claim 11, wherein the step of determining takes into consideration a vehicle position error.

Claim 15

A map drawing method according to claim 11, wherein the step of generating an image includes accessing a map buffer and further includes the steps of: writing data of a second map showing the presently-traveled road into the map buffer; and generating the image of the presently-traveled road from the data written into the map buffer.

Claim 16

A map drawing method according to claim 13, wherein if a scale of the map is 1/n while the scale of the second map is 1/m where m<n, the image of the presently-traveled road is displayed at a scale of m/n.

Claim 17

A map drawing method according to claim 14, wherein the image of the presently-traveled road is adjusted if an amount of the data exceeds a predetermined value.

Claim 18

A map drawing method according to claim 11, wherein the step of generating an image includes accessing a memory and further includes the steps of: obtaining data defining a road passing the vehicle position, and storing the obtained data in the memory; and generating the image of the presently-traveled road from the stored data.

Claim 19

A navigation apparatus in which a map showing a present vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the apparatus comprising: a traveled road image generating section which determines whether a presently-traveled road is displayed according to whether the vehicle position is on a presently displayed road or whether the vehicle position is within a predetermined distance of a presently displayed road, the traveled road image generating section generating an image of the presently-traveled road using data pertaining to the presently-traveled road, if the presently-traveled road is not already displayed on the map; and an image synthesis section coupled to the traveled road image generating section and which displays the image of the presently-traveled road by superimposing the image of the presently-traveled road on the displayed map that did not otherwise display the presently-traveled road.

Claim 20

A navigation apparatus in which a map showing a present vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the apparatus comprising: a traveled road image generating section which determines whether a presently-traveled road is displayed according to whether the vehicle position is on a presently displayed road or whether the vehicle position is within a predetermined distance of a presently displayed road, the traveled road image generating section generating an image of the presently-traveled road using data pertaining to the presently-traveled road, if the presently-traveled road is not already displayed on the map; and an image synthesis section coupled to the traveled road image generating section and which displays the image of the presently-traveled road by superimposing the image of the presently-traveled road on the displayed map that did not otherwise display the presently-traveled road.

Claim 21

A navigation apparatus according to claim 17, wherein if the presently-traveled road branches before reaching a road displayed on the map, the branch roads are displayed.

Claim 22

A navigation apparatus according to claim 17, wherein the traveled road image generating section includes a map buffer, and wherein the traveled road image generating section writes data of a second map showing the presently-traveled road into the map buffer and generates the image of the presently-traveled road from the data written into the map buffer.

Claim 23

A navigation apparatus according to claim 19, wherein if a scale of the displayed map is 1/n while the scale of the second map is 1/m where m<n, the image of the presently-traveled road is displayed at a scale of m/n.

Claim 24

A navigation apparatus according to claim 20, wherein the image of the presently-traveled road is adjusted if an amount of the data exceeds a predetermined value.

Claim 25

A navigation apparatus according to claim 17, wherein the traveled road image generating section includes a memory, and wherein the traveled road image generating section obtains data defining a road passing the vehicle position, stores the obtained data in the memory, and generates the image of the presently-traveled road from the stored data.

Claim 26

A map drawing method in which a map showing a present vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the method comprising the steps of: determining whether a presently-traveled road is displayed on the map; displaying the image of the presently-traveled road by superimposing the generated image on the displayed map; wherein the step of generating an image includes accessing a map buffer and further includes the steps of; writing data of a second map containing the presently-traveled road into the map buffer; and generating the image of the presently-traveled road from the data written into the map buffer; and wherein of a scale of the displayed map is 1/n while the scale of the second map is 1/m where m<n, the image of the presently-traveled is displayed at a scale of m/n.

Claim 27

A map drawing method in which a map showing a present vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the method comprising the steps of: determining whether a presently-traveled road is displayed on the map; displaying the image of the presently-traveled road by superimposing the generated image on the displayed map; wherein the step of generating an image includes accessing a map buffer and further includes the steps of; writing data of a second map containing the presently-traveled road into the map buffer; and generating the image of the presently-traveled road from the data written into the map buffer; and wherein of a scale of the displayed map is 1/n while the scale of the second map is 1/m where m<n, the image of the presently-traveled is displayed at a scale of m/n.

Claim 28

A map drawing method in which a map showing a vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the method comprising the steps of: determining whether a presently-traveled road is displayed according to whether the vehicle position is on a presently displayed road or whether the vehicle position is within a predetermined distance of a presently displayed road; generating an image of the presently-traveled road using data pertaining to the presently-traveled road if the presently-traveled road is not displayed; and displaying the image of the presently-traveled road on the display screen by superimposing the image on the displayed map; wherein the step of generating an image includes accessing a map buffer and further includes the steps of; writing data of a second map showing the presently-traveled road into the map buffer; and generating the image of the presently-traveled road from the data written into the map buffer; and wherein if a scale of the map is 1/n while the scale of the second map is 1/m where m<n, the image of the presently-traveled road is displayed at a scale of m/n.

Claim 29

A map drawing method in which a map showing a vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the method comprising the steps of: determining whether a presently-traveled road is displayed according to whether the vehicle position is on a presently displayed road or whether the vehicle position is within a predetermined distance of a presently displayed road; generating an image of the presently-traveled road using data pertaining to the presently-traveled road if the presently-traveled road is not displayed; and displaying the image of the presently-traveled road on the display screen by superimposing the image on the displayed map; wherein the step of generating an image includes accessing a map buffer and further includes the steps of; writing data of a second map showing the presently-traveled road into the map buffer; and generating the image of the presently-traveled road from the data written into the map buffer; and wherein if a scale of the map is 1/n while the scale of the second map is 1/m where m<n, the image of the presently-traveled road is displayed at a scale of m/n.

Claim 30

A navigation apparatus in which a map showing a present vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the apparatus comprising: traveled road image generating section which determines whether a presently-traveled road is displayed according to whether the vehicle position is on a presently displayed road, the traveled road image generating section generating an image of the presently-traveled road is not displayed; and an image synthesis section coupled to the traveled road image generating section and which displays the image of the presently-traveled road by superimposing the image on the displayed map; wherein the traveled road image generating section includes a map buffer; and wherein the traveled road image generating section writes data of a second map showing the presently-traveled road into the map buffer and generates the image of the presently-traveled road from the data written into the map buffer; and wherein if the scale of the displayed map is 1/n while wherein the scale of the second map is 1/m where m<n, the image of the presently-traveled road is displayed at a scale of m/n.

Claim 31

A navigation apparatus in which a map showing a present vehicle position is displayed while a mark representing the vehicle position is displayed on the map, the apparatus comprising: traveled road image generating section which determines whether a presently-traveled road is displayed according to whether the vehicle position is on a presently displayed road, the traveled road image generating section generating an image of the presently-traveled road is not displayed; and an image synthesis section coupled to the traveled road image generating section and which displays the image of the presently-traveled road by superimposing the image on the displayed map; wherein the traveled road image generating section includes a map buffer; and wherein the traveled road image generating section writes data of a second map showing the presently-traveled road into the map buffer and generates the image of the presently-traveled road from the data written into the map buffer; and wherein if the scale of the displayed map is 1/n while wherein the scale of the second map is 1/m where m<n, the image of the presently-traveled road is displayed at a scale of m/n.