Method for converting coordinate values of map data

• US 7,197,393 B2
• Filed: 01/19/2005
• Issued: 03/27/2007
• Est. Priority Date: 01/20/2004
• Status: Expired due to Fees

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Young-In
• Primary Examiner(s): Camby; Richard M.
• Application Number:
  US11/039,616
• Publication Number:
  US 20050159886A1
• Time in Patent Office: 797 Days
• Field of Search: 701200-213, 701/300, 701/220, 701/221, 340/990, 3409951-99528
• US Class Current: 701/208
• CPC Class Codes: G01C 21/387 Organisation of map data, e.g. version management or database structures
• CPC Class Codes: G09B 29/106 using electronic means

Abstract

The present invention relates to a method for converting coordinate values of map data, wherein three-dimensional effects are displayed on a screen by converting two-dimensional coordinate values of objects constituting a map without using a three-dimensional graphic library and an additional storage space.

In the method of the present invention, two-dimensional map data for a certain area including a reference position are loaded from a map data storage unit and then moved with respect to the reference position and a sight line along which the two-dimensional map data are viewed from the reference position; an XY coordinate system with an origin of a central position of the moved two-dimensional map data is defined and coordinate values of objects constituting the two-dimensional map data are converted into coordinate values in the XY coordinate system; and Y-axis coordinate values obtained through the XY coordinate conversion of the two-dimensional map data are converted on a reduced scale at a reduction ratio predetermined according to the Y-axis coordinate values, and X-axis coordinate values of the objects in a digital map with the reduced Y-axis coordinate values are converted on an enlarged or reduced scale according to a predetermined X-axis coordinate value conversion function, thereby displaying the map on the screen while representing three-dimensional effects.

Claims

1. A method for converting coordinate values of map data, comprising:

a map data loading step of loading, by a control unit, two-dimensional map data from a map data storage unit;

an XY coordinate converting step of defining an XY coordinate system with an origin of a central position of the two-dimensional map data loaded in the map data loading step, and converting coordinate values of objects constituting the two-dimensional map data into coordinate values in XY coordinate system; and

a coordinate value converting step of converting Y-axis coordinate values of the objects obtained through the XY coordinate converting step on a reduced scale at a reduction ratio predetermined according to the Y-axis coordinate values, and converting X-axis coordinate values thereof by substituting them into a predetermined X-axis coordinate value conversion function.

2. The method as claimed in claim 1, wherein the conversion of the Y-axis coordinate values in the coordinate value converting step comprises the steps of:

dividing the map data into a region of Y>

0 and a region of Y≦

0 along a Y-axis,

setting reduction ratios for the divided regions such that a higher reduction ratio is applied to the region of Y>

0 than the region of Y≦

0, and

converting the Y-axis coordinate values of the plurality of objects on the reduced scale at the set reduction ratios.

3. The method as claimed in claim 1, wherein the conversion of the Y-axis coordinate values in the coordinate value converting step comprises the steps of:

dividing the map data into a plurality of uniform regions along a Y-axis,

setting reduction ratios for the divided regions such that higher reduction ratios are applied to regions with higher Y-axis coordinate values, and

converting the Y-axis coordinate values of the plurality of objects in the respective regions on the reduced scale at the set reduction ratios.

4. The method as claimed in claim 1, wherein the conversion of the Y-axis coordinate values in the coordinate value converting step comprises the steps of:

dividing the map data into a plurality of regions along a Y-axis such that regions with higher Y-axis coordinate values become smaller,

setting reduction ratios for the divided regions such that higher reduction ratios are applied to regions with higher Y-axis coordinate values, and

converting the Y-axis coordinate values of the plurality of objects on the reduced scale at the set reduction ratios.

5. The method as claimed in claim 1, wherein the X-axis coordinate value conversion function in the coordinate value converting step is the following equation 1:

$\begin{array}{cc}B<br><br>\left(x,y\right)=\left(\frac{4<br><br>b-y}{3<br><br>b},y\right)& \left(1\right)\end{array}$

wherein B(x, y) is the X-axis coordinate value conversion function and b is a Y-axis coordinate value of a reference point for generating the X-axis coordinate value conversion function.

6. The method as claimed in claim 1, after the coordinate value converting step, further comprising the step of outputting the map data with the converted X-axis and Y-axis coordinate values to a display driving unit so that the map data can be displayed on a screen.

7. A method for converting coordinate values of map data, comprising:

a map data loading step of loading, by a control unit, two-dimensional map data for an input area including a reference position from a map data storage unit;

a map data moving step of shifting and rotating coordinate values of the two-dimensional map data loaded in the loading step with respect to the reference position and a sight line along which the two-dimensional map data are viewed from the reference position;

an XY coordinate converting step of defining an XY coordinate system with an origin of a central position of the two-dimensional map data moved in the map data moving step, and converting coordinate values of objects constituting the two-dimensional map data into coordinate values in the XY coordinate system; and

a coordinate value converting step of converting Y-axis coordinate values of the objects obtained through the XY coordinate converting step on a reduced scale at a reduction ratio predetermined according to the Y-axis coordinate values, and converting X-axis coordinate values thereof by substituting them into a predetermined X-axis coordinate value conversion function.

8. The method as claimed in claim 7, wherein the reference position in the loading step and the moving step is a current vehicle location detected from a navigation message received by a GPS receiver or from detection signals of a sensor unit installed on a vehicle.

9. The method as claimed in claim 7, wherein the reference position in the loading step and the moving step is a position input by a user through a command input unit.

10. The method as claimed in claim 7, wherein the sight line in the moving step is a direction in which a vehicle travels from the reference position.

11. The method as claimed in claim 7, wherein the conversion of the Y-axis coordinate values in the coordinate value converting step comprises the steps of:

dividing the map data into a region of Y>

0 and a region of Y≦

0 along a Y-axis,

setting reduction ratios for the divided regions such that a higher reduction ratio is applied to the region of Y>

0 than the region of Y≦

0, and

converting the Y-axis coordinate values of the plurality of objects on the reduced scale at the set reduction ratios.

12. The method as claimed in claim 7, wherein the conversion of the Y-axis coordinate values in the coordinate value converting step comprises the steps of:

dividing the map data into a plurality of uniform regions along a Y-axis,

setting reduction ratios for the divided regions such that higher reduction ratios are applied to regions with higher Y-axis coordinate values, and

converting the Y-axis coordinate values of the plurality of objects in the respective regions on the reduced scale at the set reduction ratios.

13. The method as claimed in claim 7, wherein the conversion of the Y-axis coordinate values in the coordinate value converting step comprises the steps of:

dividing the map data into a plurality of regions along a Y-axis such that regions with higher Y-axis coordinate values become smaller,

setting reduction ratios for the divided regions such that higher reduction ratios are applied to regions with higher Y-axis coordinate values, and

converting the Y-axis coordinate values of the plurality of objects on the reduced scale at the set reduction ratios.

14. The method as claimed in claim 7, wherein the X-axis coordinate value conversion function in the coordinate value converting step is the following equation 1:

$\begin{array}{cc}B<br><br>\left(x,y\right)=\left(\frac{4<br><br>b-y}{3<br><br>b},y\right)& \left(1\right)\end{array}$

wherein B(x, y) is the X-axis coordinate value conversion function and b is a Y-axis coordinate value of a reference point for generating the conversion function.

15. The method as claimed in claim 7, after the coordinate value converting step, further comprising the step of outputting the map data with the converted X-axis and Y-axis coordinate values to a display driving unit so that the map data can be displayed on a screen.