JP2006058530A - Map display device and navigation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance visibility of a map displayed on a screen by stereoscopically displaying the map. <P>SOLUTION: When displaying a map on a display device 7, a control circuit 2 controls display so that a specific background polygon showing a green space is displayed in a stereoscopic way like being raised in a trapezoidal shape, and a specific background polygon showing a water body is displayed in a stereoscopic way like being depressed in an inverted trapezoidal shape. In a two-dimensional display mode, the specific background polygon is displayed after reduction conversion is applied to it with its center-of-gravity as the center, and an area between the polygon after the reduction conversion and the specific background polygon before the reduction conversion is displayed as a frame polygon. Then, assuming how the specific background polygon is viewed under a light source at a prescribed position, a color for expressing shade is added on the upper face of the specific background polygon and on the side face shown by the frame polygon. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a map display device and a navigation device that display each component of a map on a screen based on map data.

When displaying a polygon (referred to as a background polygon) representing a green space or a water area on the screen of the navigation device, the visibility is improved by changing the color or texture pattern (pattern) according to the type of the background polygon. Further, in Patent Document 1, when a road map is three-dimensionally displayed along with terrain, in order to reliably display the presence of depressed terrain portions such as rivers, lakes, ponds, etc., regardless of the viewpoint altitude of the display screen. In addition, a technique for displaying a region corresponding to a water area in a color for displaying the water area when the water area is not displayed due to being hidden by a display target on the near side on the screen being displayed is disclosed.
JP 2000-322593 A

  In the conventional two-dimensional display, for example, a green area is displayed in green and a water area is displayed in light blue or blue. However, the background polygons of green spaces and water areas are unlikely to appear in the shape, etc. unlike roads and buildings, etc., and are expressed in a single color, and are only a background for the user. There is a problem that it is difficult to recognize in the display. In the three-dimensional display, the background polygon that does not have the height data as the map data is only displayed in a two-dimensional manner, and there is a problem in recognition as in the two-dimensional display.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a map display device with improved visibility of a map displayed on a screen and a navigation device using the map display device.

  According to the means described in claim 1, when each component of the map is displayed on the screen based on the map data, the polygon is a polygon representing a planar natural object (not a structure) such as a green space or a water area. Since the data that does not have height data is displayed in a three-dimensional form so as to have a trapezoidal cross section, the green space or water area is raised or raised in either the 2D display mode or the 3D display mode. It is displayed in a depressed shape, and the visibility of these green areas, water areas and the entire map is improved.

  Many green spaces and water areas displayed on the map have a larger area compared to structures such as roads and buildings, and because there are few dots as structures, there are complex uplifts and depressions on the screen display. It is considered that the visibility is unlikely to occur with little assembly. In addition, since the cross section is trapezoidal, it is possible to give a natural impression that gradually rises or sinks at the edge, unlike a building whose wall surface stands vertically. The trapezoid referred to here includes both those having an upper base <lower base relationship and those having an upper base> lower base relationship (so-called inverted trapezoid).

  According to the means described in claim 2, even when a map is displayed in two dimensions, a frame polygon representing a side surface is added along the outer periphery of the polygon, and a color representing a shadow is added to the frame polygon. Display can be performed.

  According to the means described in claim 3, the polygon is reduced and converted with the center of gravity as the center, and the region sandwiched between the reduced polygon and the original polygon is displayed as a frame polygon. The original polygon can be displayed in three dimensions while maintaining the size of the polygon.

  According to the means described in claim 4, when the map is displayed three-dimensionally, first, predetermined height data is given to the polygon, and then a three-dimensional display is performed by the same processing as that of a building having the height data. Therefore, an increase in processing load on the map display device can be suppressed as much as possible.

  According to the means described in claim 5, when the map is displayed three-dimensionally, constant height data is given for each type of polygon (for example, green space, water area, etc.). A plurality of regions having a height do not exist, the map display is simplified, and the visibility is further enhanced. In addition, an increase in processing load on the map display device can be suppressed.

  According to the means described in claim 6, the green space in the map is displayed in a three-dimensional shape in a raised shape so as to have a trapezoidal cross section, and the water areas such as rivers, ponds, lakes, and seas in the map are trapezoidal ( More specifically, since it is displayed in a three-dimensional shape in a depressed shape so as to have a cross-section of an inverted trapezoidal shape, it is easy to match an image held by a person, and the visibility is further improved.

  Since the navigation device described in claim 7 includes the map display device described above, the visibility of the driver's map is improved and a safer and more comfortable guidance service can be received.

Hereinafter, an embodiment in which the present invention is applied to a car navigation apparatus will be described with reference to the drawings.
FIG. 1 is a block diagram schematically showing the overall electrical configuration. In FIG. 1, a car navigation device 1 (corresponding to a navigation device and a map display device) includes a control circuit 2, a position detector 3, a map data input device 4, and an operation switch group 5 connected to the control circuit 2, respectively. , An external memory 6, a display device 7, an external information input / output device 8, a remote control sensor 9 and a remote control 10.

The control circuit 2 (corresponding to the display control means) has a function of controlling the overall operation of the car navigation apparatus 1 and is mainly composed of a microcomputer. The control circuit 2 includes a CPU, a ROM, a RAM, an I / O interface, a bus that connects these, and the like (all not shown).
The ROM stores a navigation execution program for the car navigation device 1 to execute a navigation operation. The RAM temporarily stores temporary data during program execution, map data acquired from the map data input device 4, and the like.

  The position detector 3 serving as position detecting means includes a geomagnetic sensor 11, a gyroscope 12, a distance sensor 13, and a GPS receiver 14, and detects the current position information of the vehicle. Since each component of the position detector 3 has a detection error having a different property, the control circuit 2 uses the signal inputs from the position detector 3 while interpolating each other, so that the current position of the vehicle, the progress of the vehicle The direction, speed, mileage, etc. can be detected with high accuracy. The position detector 3 does not have to include all the components as long as the current position can be detected with the required detection accuracy. Further, the position detector 3 may be configured by combining a rotation sensor for a steering wheel, a wheel sensor for detecting rotation of each tire, and the like.

  The map data input device 4 is configured to read data from a map disk 15 made of an information recording medium such as a DVD-ROM. In this case, the map disk 15 includes map data, map matching data for improving position detection accuracy, landmark data of various buildings including building height data and shape data, a store / facility name database, a telephone number and Various data such as a telephone number database indicating correspondence with a store / facility and information on a WEB page provided by the store / facility are recorded. For example, a CD-ROM or a memory card may be used as the information recording medium.

  The external memory 6 is configured by a flash memory card or the like, and stores, for example, guidance route data to a destination obtained by route calculation processing by the control circuit 2. The function of the external memory 6 can be realized by a storage element (such as a RAM) in the control circuit 2. In this case, the external memory 6 may be provided as necessary.

  The display device 7 as a display means includes, for example, a color liquid crystal display for displaying a map screen or the like, and is installed in the vicinity of the driver's seat of the vehicle. On the screen of the display device 7, a road map is displayed, and a pointer indicating the current position and traveling direction of the vehicle is displayed so as to be superimposed on the display. In addition, when performing route guidance based on the route calculation result to the destination, the guidance route to be traveled while being superimposed on the road map is displayed (see FIG. 5).

  The operation switch group 5 includes mechanical switches arranged around the display device 7, touch switches formed on the color liquid crystal display of the display device 7, and the like, and is used for inputting setting items. The remote control sensor 9 receives an operation input from the remote control 10 and gives it to the control circuit 2.

  The external information input / output device 8 includes, for example, a VICS communication device or a mobile phone (a dedicated mobile phone terminal, a general-purpose mobile phone, or the like). The control circuit 2 can transmit / receive data to / from an external information supply center such as a VICS center or various information centers via the external information input / output device 8.

  As a basic function of the control circuit 2 of the car navigation device 1, a driver (may be another user who rides) sets the destination by operating the operation switch group 5, the touch switch of the display device 7 or the remote control 10. Then, the route calculation function that calculates the guidance route data from the current position to the destination, the route guidance function that displays the route indicated by the guidance route data on the map screen or by voice guidance, the map that positions the current position on the map It has a matching function. When inputting the destination, the display device 7 displays the index of the store / facility name database and the index of the telephone number database, and the destination can be selected from the index.

Next, the contents of the map display process executed by the car navigation device 1 will be described with reference to FIGS.
FIG. 5 shows a screen display example when a wide area map is displayed on the display device 7 in the two-dimensional display mode. For example, when the route guidance is executed, the control circuit 2 displays a map, a pointer P indicating the current position, the operation guidance buttons B (B1 to B6), and the like on the screen of the display device 7, and the guidance route N calculated in advance is a solid line To highlight. In FIG. 5, the pointer P is represented by a mark that models the shape of the automobile and a ring with a shadow.

  When the vehicle advances in this display state, it is necessary to update the map display on the screen. FIG. 2 shows a flowchart of this map display update process. First, in step S1, the control circuit 2 determines a map range to be newly displayed in relation to the vehicle position, and proceeds to step S2 to display the map to be displayed from the map disk 15 via the map data input device 4. Enter the data. The input map data is temporarily stored in a RAM or the like in the control circuit 2.

  Subsequently, drawing of map data is started. Drawing is first performed on background elements such as residential areas, flat areas, fields, green spaces, and water areas, and then on structures such as roads and buildings. In step S3, the control circuit 2 is a planar natural object in which the drawing element constitutes the background and does not include height data in the map data (a polygon representing such an element is hereinafter referred to as a specific background polygon). Determine whether or not. In this embodiment, green spaces and water areas (rivers, ponds, lakes, seas, etc.) are regarded as specific background polygons. If “YES” is determined in step S3, processing specific to the specific background polygon is performed in steps S4 to S8. After that, a drawing process is performed in step S9.

  On the other hand, if it is a flat natural object constituting the background, such as a residential area, a flat area, a field, or a structure such as a road or a building, “NO” is determined in step S3 and the step is performed. The process shifts to S9 and the same drawing process as the conventional one is performed. That is, a residential area, a flat area, a field, a road, and the like are drawn in a planar manner, and a building having shape data is displayed in a planar or stereoscopic manner. The three-dimensional display of the building is performed by applying a shadow to the shape viewed from above using the shape data included in the map data. However, in the display method with shadows, the building appears to float. When drawing for one display element is completed, the process proceeds to step S10 to determine whether or not all display processes have been completed. When it is determined that the display process has been completed (YES), the update process is terminated and not completed (NO). If it is determined, the process proceeds to step S3, the next drawing element stored in the RAM is taken out, and the drawing process is continued.

  Now, the processing from step S4 to S8 will be described. FIG. 3 shows a process of processing a rectangular specific background polygon three-dimensionally. The control circuit 2 calculates the centroid position of the specific background polygon in step S4 (see FIG. 3A), and calculates the coordinates after the reduction conversion centered on the centroid position in step S5 (FIG. 3B). reference). Subsequently, in step S6, an area sandwiched between the polygon after reduction conversion and the original specific background polygon before reduction conversion is set as a frame polygon. This frame polygon represents the side surface of the specific background polygon along the outer periphery of the original specific background polygon (see FIG. 3C).

  Further, in step S7, the control circuit 2 selects whether to display a raised shape or a depressed shape according to the type of the specific background polygon. In the present embodiment, the polygon representing the green space is displayed in a three-dimensional shape in a raised shape so as to have a trapezoidal cross section, and the polygon representing the water area has a trapezoidal (more specifically, a so-called inverted trapezoidal) cross section. Is displayed in a three-dimensional depression. FIG. 4 shows a screen display of the green area and the water area when the green area and the water area are displayed in the three-dimensional display mode and the viewpoint is brought to the position of 0 m. The height of the specific background polygon in the two-dimensional display or the three-dimensional display may be constant for each type of polygon (green space, water area).

  In step S8, the control circuit 2 assumes the appearance of the specific background polygon under the light source at a predetermined position, and adds a color representing a shadow to the upper surface of the specific background polygon and the side surface indicated by the frame polygon. FIG. 3D shows a display example when it is assumed that there is a light source in the upper left direction of the drawing. In the case of a raised green area, the upper and left frame polygons (outer surfaces) in FIG. 3 (d) are displayed in bright colors, and in the case of a depressed green area, the lower and right sides of FIG. 3 (d) are displayed. The frame polygon (inner side) is displayed in a bright color. Thereafter, the control circuit 2 draws the three-dimensional specific background polygon in step S9. FIG. 5 is an example of a display screen drawn in this way, and green spaces G1 to G4 and a river R1 are displayed in three dimensions as specific background polygons. In the case of the three-dimensional display mode, it is only necessary to give certain height data to a specific background polygon representing a green area and a water area, and then draw it in the same manner as a building having height data.

  As described above, in the car navigation device 1 of the present embodiment, the polygon representing the green area is displayed in a three-dimensional manner as if it is raised in a trapezoidal shape, and the polygon representing the water area is depressed in an inverted trapezoidal shape. Thus, the green area and the water area are appropriately emphasized with respect to other backgrounds and structures, and the visibility of the entire map as well as the green area and the water area is improved. In addition, since the specific background polygon is displayed so as to look like a trapezoidal shape or an inverted trapezoidal shape, it is possible to give a natural impression that the wall portion gradually rises or sinks unlike a building whose wall surface stands vertically. Furthermore, each surface of the specific background polygon to which the frame polygon is added has a shaded color from the relationship with the virtual light source position, so that a more realistic stereoscopic effect can be obtained.

Since the specific background polygon is three-dimensionally displayed so as to have a certain height according to the type (green space, water area), the map display is simplified and the visibility is further improved. In addition, since it is not necessary to have height data for each specific background polygon, the conventionally used map disk 15 can be used as it is.
When displaying a specific background polygon three-dimensionally in 2D display, the area between the reduced specific polygon and the original specific background polygon is displayed as a frame polygon on the side. The size of the specific background polygon is maintained, and the positional relationship and size relationship with other display elements do not change.

The present invention is not limited to the embodiment described above and shown in the drawings. For example, the present invention can be modified or expanded as follows.
The present invention is not limited to car navigation devices and can be widely applied to other types of navigation devices such as portable devices, map display devices, map drawing on the screens of personal computers and portable terminal devices, and the like. Further, the present invention can be applied not only to wide area display but also to other map display such as city area display.

  In the above embodiment, the polygon indicating the green area and the water area is the specific background polygon. However, if the polygon is a polygon that represents a planar natural object among the components of the map display and does not have height data in the map data, other polygons may be used. These elements may be specified background polygons. For example, in a region where fields and residential areas are mixed, the fields may be displayed three-dimensionally as specific background polygons. Further, in a region where narrow green spaces and lakes are scattered, or in a region where rivers are complicatedly crossed, the image may be displayed in a planar manner as usual without being three-dimensionalized. Furthermore, the number and size of green spaces, water areas, fields, etc. in the map displayed by the control circuit 2 may be counted (measured) to automatically switch between the three-dimensional display and the flat display. Alternatively, it may be configured such that the user can switch the display mode by manual operation or voice operation.

  The height at which the specific background polygon is displayed, that is, the height of the frame polygon (side surface) may not be constant for each type. For example, the height may be changed according to the area of the specific background polygon. In the three-dimensional display mode, the height may be changed according to the distance from the viewpoint position. As an example, further improvement in visibility can be expected by displaying a higher specific background polygon that appears farther away.

1 is a block diagram schematically showing an electrical configuration of a car navigation device according to an embodiment of the present invention. Flow chart showing map display update process Diagram showing the process of processing a rectangular specific background polygon in three dimensions Diagram showing the screen display when the viewpoint is brought to the 0m position in the 3D display mode The figure which shows the example of a screen display when a wide area map is displayed in 2D display mode

Explanation of symbols

Reference numeral 1 denotes a car navigation device (navigation device, map display device), and 2 denotes a control circuit (display control means).

Claims (7)

In a map display device that displays each component of a map on the screen based on map data,
For the polygons representing planar natural objects such as green spaces and water areas among the constituent elements that do not have height data in the map data, the polygons are raised or depressed so as to have a trapezoidal cross section. A map display device comprising display control means for three-dimensional display.   When the map is displayed two-dimensionally, the display control means adds a frame polygon representing a side surface along the outer periphery of the polygon, and adds a color representing a shadow to the frame polygon to display it three-dimensionally. The map display device according to claim 1.   The display control means displays the polygon with a reduced conversion centered on the center of gravity, and displays a region sandwiched between the reduced conversion polygon and the reduced conversion polygon as a frame polygon. The map display device according to claim 2.   2. The map display device according to claim 1, wherein when the map is displayed three-dimensionally, the display control means displays the map three-dimensionally after giving predetermined height data to the polygon.   5. The map display device according to claim 4, wherein the display control means gives a constant height data for each type of the polygon.   The display control means displays the green space in the map in a three-dimensional shape so as to have a trapezoidal cross section, and the water areas such as rivers, ponds, lakes, and seas in the map have a trapezoidal cross section. 6. The map display device according to claim 1, wherein the map display device is three-dimensionally displayed in a depressed shape. A navigation device comprising the map display device according to claim 1.

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