JP2008151750A - Map display device and map scrolling technique - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a map display device and a map scrolling technique capable of alleviating load of scrolling processing effectively. <P>SOLUTION: The map display device 10 is equipped with a displaying section 18 and displays map imageries on the displaying section 18 including a current position or a sites desired. When a drawing processing application 111 displays unit map data, a drawing timekeeping section 14 measures drawing time, and when the drawing processing application 111 implementing scroll processing to the map imageries, if the drawing time exceeds a predetermined threshold, a drawing method altering section 19 selects the data using a drawing method with large processing load from data included in the unit map data for which different drawing methods are used to alter to a drawing method of small processing load, and the drawing method altering section 19 implements drawing processing of map data based on the altered drawing method to scroll the map imageries displayed on the displaying section 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a map display device such as an in-vehicle navigation device and a map scroll method, and in particular, in order to reduce the load on the control means in the scroll processing, the drawing load during the map display processing is used as the drawing time. If the drawing load exceeds the predetermined load, the drawing processing of data with a large processing load among the data with different drawing methods included in the map data is changed to a drawing method with a low processing load and processed. Thus, the present invention relates to a map display device and a map scrolling method in which the influence of appearance in map observation is reduced.

  2. Description of the Related Art There are known navigation devices and navigation systems that guide a user by searching for a route from a desired departure point to a destination using map data and road data. As such navigation devices and navigation systems, automobiles are known. Car navigation device that is installed in the vehicle to guide the route to the driver, a communication navigation system that sends a route search request to the route search server using a mobile phone as a navigation terminal, receives the result, and receives route guidance, etc. Has been put to practical use.

  In the navigation system, a map image is displayed centering on the current position based on a predetermined range of map data including the current position of a vehicle or a pedestrian, and a guide route and a current position mark are superimposed on the map image. Is done. The displayed map image is also a building image or icon image showing buildings, government offices, schools, hospitals, banks, post offices, etc., which are famous landmarks, or various interests such as gas stations and convenience stores. An icon image indicating a location (POI) is also included.

  The map data is generally vector map data, and is composed of mesh unit map data divided by a predetermined latitude / longitude range. Such map data is stored in storage means such as a CD-ROM, and unit map data required for display is read from the storage means and displayed on the display unit. The communication type navigation system adopts a configuration in which map data is downloaded from a server.

  In addition to road vectors and terrain data, vector map data includes building location information, building images or icon images that indicate famous landmark buildings, government offices, schools, hospitals, banks, post offices, etc. This includes location information and icon images of various places of interest (POI) such as stands and convenience stores.

  In the navigation device, since the vehicle and the pedestrian move on the guided route, the map image displayed on the display unit is also scrolled along with the change of the current position. In general, the display unit is composed of a liquid crystal display unit or the like, and an image to be displayed is developed as a bitmap in a video RAM (VRAM). The scrolling process is performed by sequentially shifting the bitmap data developed in the VRAM based on the moving direction and moving amount of the current position and the map data.

  For example, in the following Patent Document 1 (Japanese Patent Laid-Open No. 9-81084), the VRAM update time is increased due to a large amount of update of display data by scroll display of a display image, and the display screen itself has a memory property. There has been disclosed a display device that has solved the problem of lengthening the update time of the display image itself that occurs in the case of a display device having a display.

In the display image scroll mode, the display device disclosed in Patent Document 1 transmits data with coarse pixels, and by using this data, a partial area of the display screen of the image display means is used. By scrolling, the data transmission time and the image display control time are shortened, the time until the user searches for the required image information is shortened, and a comfortable user interface is provided. In the middle of scrolling, the display image is transmitted less than the display data of the entire screen of the display device, and the display signal processing is performed to provide a display device with low power consumption as a whole system. is there.
JP-A-9-81084 (FIG. 3, paragraph [0031])

  By the way, in a map display device equipped with image processing application software that does not have high drawing performance (not high processing capacity) such as an in-vehicle navigation device, when scrolling a map image, the target map data is an urban area, etc. When scroll processing occurs in a state where a map having a relatively large amount of data is displayed, there is a problem that the scroll speed is reduced and the movement of the displayed map image is slowed down.

  If the map data is simply thinned out as in the map display device disclosed in Patent Document 1 so as not to reduce the scrolling speed, the appearance of a map image in a place with a small amount of data such as a suburb or countryside is deteriorated. . This is because the image displayed on the display unit is sparse due to the thinning of data.

  Even if the amount of road and terrain data required for a map image is small, various places of interest such as landmark buildings, government offices, schools, hospitals, banks, post offices, gas stations, convenience stores, etc. In the case of map data with many (POI), the load of drawing processing may become heavy. Conversely, even if the amount of road and terrain data required as a map image is large, various buildings such as landmark buildings, government offices, schools, hospitals, banks, post offices, gas stations, convenience stores, etc. In the case of map data with few places of interest (POI), the load of the drawing process may be reduced.

  When road shape data is prepared with polygon data and displayed three-dimensionally, or a building or POI image is drawn, it is displayed as a polygon, displayed as a polygon, or textured on a polygon-displayed shape image. Various drawing methods such as pasting are used. Depending on each drawing method, the load of the drawing process can be reduced or increased. If data of a drawing method with a heavy drawing processing load is drawn as it is, there is a problem that the scroll processing time is slow.

  Although it is possible to perform thinning according to the amount of map data to be displayed, however, as described above, the image processing application only draws data with a heavy drawing load, or relatively, only with the amount of map data. There was a problem that it was not possible to determine whether the data was drawn with a light load.

  The inventor of the present application has conducted various studies to solve the above-described problems. As a result, in order to reduce the load of the control means in the map image scrolling process, the drawing load at the time of the map display process is calculated. If the drawing method exceeds the specified load, if the drawing processing of data with a high processing load among the data with different drawing methods included in the map data is changed to a drawing method with a low processing load, the drawing method Even if the change is made, the effect of appearance on the map observation is small, and the present invention has been completed by conceiving that the above problems can be solved.

  That is, the present invention aims to solve the above-described problems, and in a map display device that displays a map image on a display means and displays the current position on the map image, the load of scroll processing is effectively reduced. An object of the present invention is to provide a map display device and a map scroll method that can be reduced.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is
A map display device that includes a map data storage unit that stores map data and a display unit, reads map data including a current position or a desired point from the map data storage unit, and displays a map image on the display unit.
The map data stored in the map data storage unit includes unit map data in which data relating to roads, terrain, buildings, and POIs in a predetermined area are accumulated according to the data type, and the map display device uses a drawing processing application. An installed control unit, a drawing time measuring unit, and a drawing method changing unit;
When the drawing processing application displays the unit map data, the drawing time measuring unit measures the drawing time, and when the drawing processing application scrolls the map image, when the drawing time exceeds a predetermined threshold, The drawing method changing unit selects data using a drawing method having a large processing load from data having different drawing methods included in the unit map data, and changes the drawing method to a drawing method having a low processing load. The map data is drawn based on the drawing method changed by the drawing method changing unit, and the map image displayed on the display unit is scrolled.

  The invention according to claim 2 of the present application is the map display device according to claim 1, wherein when the drawing time exceeds a predetermined threshold, the drawing method changing unit is a data having a different drawing method included in the unit map data. Among them, polygon data using a drawing method with a large processing load is selected and converted into plane image data with a low processing load, and the drawing method is changed.

The invention according to claim 3 of the present application is
A map scroll in a map display device that includes a map data storage unit that stores map data and a display unit, reads map data including a current position or a desired point from the map data storage unit, and displays a map image on the display unit In the method
The map data stored in the map data storage unit includes unit map data in which data relating to roads, terrain, buildings, and POIs in a predetermined area are accumulated according to the data type, and the map display device uses a drawing processing application. An installed control unit, a drawing time measuring unit, and a drawing method changing unit;
When the drawing processing application displays the unit map data, the drawing time measuring unit measures the drawing time, and when the drawing processing application scrolls the map image, the drawing time exceeds a predetermined threshold value. ,
A drawing method changing step in which the drawing method changing unit selects data using a drawing method with a large processing load from among data having different drawing methods included in the unit map data, and changes the drawing method to a drawing method with a low processing load; The drawing processing application includes a step of drawing map data based on a drawing method changed by the drawing method changing unit and scrolling a map image displayed on the display unit.

  The invention according to claim 4 of the present application is the map scrolling method according to claim 3, wherein the drawing method changing step includes a step in which the drawing method included in the unit map data is different when the time exceeds a predetermined threshold. And a process of selecting polygon data using a drawing method having a large processing load, converting the data into plane image data having a low processing load, and changing the drawing method.

In the invention according to claim 1,
The map display device includes a control unit equipped with a drawing processing application, a drawing time measuring unit, and a drawing method changing unit, and when the drawing processing application displays unit map data, the drawing time measuring unit draws When the drawing time exceeds a predetermined threshold when the drawing processing application scrolls the map image, the drawing method changing unit, among the data with different drawing methods included in the unit map data, The data using a drawing method with a large processing load is selected and changed to a drawing method with a low processing load, and the drawing processing application draws map data based on the drawing method changed by the drawing method changing unit, and Scrolls the map image displayed on the display unit.

  According to such a configuration, when the drawing time of the unit map data to be displayed exceeds a predetermined threshold, a drawing method with a large processing load is selected from among the data with different drawing methods included in the unit map data when scrolling. Since the data to be used is selected and the drawing method is changed to a drawing method with a small processing load, the drawing processing load can be reduced, and the map image can be drawn without unnaturalness.

  In the invention according to claim 2, in the map display device according to claim 1, when the drawing time exceeds a predetermined threshold, the drawing method changing unit is configured to store data of different drawing methods included in the unit map data. Among them, polygon data using a drawing method with a large processing load is selected and converted into plane image data with a low processing load to change the drawing method.

  If configured in this way, the Borgon data is converted into plane shape data and displayed in a planar manner during the scroll process, so that the load of the drawing process can be reduced, and when observing the map image displayed on the display unit, Even if an image of a road or a building is converted into a flat image and displayed, an unnatural impression is not given. Further, it is possible to prevent the scroll speed from being lowered.

  In the inventions according to claims 3 and 4, it is possible to provide a map scrolling method for realizing the map display device according to claims 1 and 2, respectively.

  Hereinafter, specific examples of the present invention will be described in detail with reference to examples and drawings. However, the embodiment shown below exemplifies a map display device for embodying the technical idea of the present invention, and is not intended to specify the present invention as the map display device of this embodiment. In addition, the present invention is equally applicable to the map display devices of other embodiments included in the scope of claims.

  FIG. 1 is a block diagram showing a configuration of a map display device 10 according to an embodiment of the present invention. The map display device 10 includes a control unit 11, a map data storage unit 12, an operation unit 13, a drawing time measurement unit 14, a current position detection unit 15, a clock unit 16, a VRAM 17, a display unit 18, a drawing method change unit 19, and the like. It is prepared for. The map display device 10 is, for example, an in-vehicle navigation device and has a route search function.

  Although not shown, the control unit 11 is a microprocessor having a RAM, a ROM, and a processor, and controls the operation of each unit by a control program stored in the ROM. The current position detection unit 15 includes a GPS receiver and self-contained navigation means, and detects the current position of the map display device 10. The GPS receiver receives signals from a plurality of GPS satellites at a constant cycle and measures the current position. The self-contained navigation means is for performing dead reckoning navigation by obtaining various sensor outputs such as an acceleration sensor and a rudder angle sensor provided in the vehicle and calculating a current position.

  The display unit 18 is a display unit including a liquid crystal display unit and the like, and displays a map image and a recommended route. The operation unit 13 includes operation buttons, a touch panel, and the like, and operates various functions of the map display device 10 and inputs necessary numerical values and characters. When a desired departure point and destination are set from the operation unit 13 and a navigation request is made, the navigation application installed in the control unit 11 is activated and the map data storage unit 12 is referenced to connect the two points at the shortest. Search for recommended routes.

  The recommended route searched by the navigation application is displayed on the display unit 18 together with the map image. The map image is displayed on the display unit 18 based on a predetermined range of map data centered on the current position calculated by the current position detection unit 15, and a current position mark indicating the current position is displayed on the map image. When displaying the map image, the map image is developed in the VRAM 17 in a bitmap format based on the map data in a predetermined range read from the map data storage unit 12. Drawing processing using the VRAM is executed by a drawing processing application 111 installed in the control unit 11.

  Further, the map display device 10 reads out a map image of a predetermined range including the desired point from the map data storage unit 12 based on the desired point input by the operation unit 13 in addition to the map image display accompanying the navigation request. Can also be displayed on the display unit 18.

  In the map display at the time of navigation, the map image is displayed so that the map display device 10, that is, the current position of the vehicle is at the center of the display screen, so that the map image scroll process as the vehicle travels on the route guided. Is done. In addition, even when a map of a desired point is displayed on the display unit 18, if the user wants to display an image that follows the displayed map image, the operation unit 13 is operated (such as a scroll button operation) to display the map image. May scroll.

  In the map image scrolling process, the map data read from the map data storage unit 12 is redrawn by developing a bitmap by shifting the dot position on the VRAM 17 in accordance with the display screen. This processing is executed by the drawing processing application 111 installed in the control unit 11. Usually, when the load of the drawing process is large, the scrolling speed of the map image is reduced. Therefore, as disclosed in Patent Document 1, generally, the drawing process is performed by thinning out the map data at a predetermined interval.

  When the map image is displayed by simply thinning out the map data, as described above, the image processing application is drawing data with a heavy drawing load or drawing with a relatively light load only with the amount of map data. It is not possible to determine whether the data is to be used. If data is thinned out uniformly, the appearance of a map image of a place with a small amount of data such as a suburb or countryside will deteriorate. This is because the image displayed on the display unit is sparse due to the thinning of data.

  In addition to road and terrain data required as map images, the map data includes landmarks such as buildings, government offices, schools, hospitals, banks, post offices, and various interests such as gas stations and convenience stores. The location (POI) name, position data, its icon image, building image, and the like are included. These data are stored as data corresponding to the drawing method. For example, as described above, when road shape data is prepared with polygon data and displayed three-dimensionally, or when a building or POI image is drawn, it is displayed as a polygon, displayed as a polygon, or displayed as a polygon. Various drawing methods, such as attaching a texture to the shape image, are adopted. Depending on each drawing method, the load of the drawing process can be reduced or increased. If data of a drawing method with a large drawing processing load is drawn as it is, the scroll processing time is delayed.

  In the map display device 10 according to the present invention, paying attention to the fact that, when drawing a road, building, or POI image, changing the drawing method does not significantly affect the observation of the displayed map image. When displaying map data with a high drawing processing load, change the drawing processing of data that uses a drawing method with a large processing load to a drawing method with a low processing load from among the data with different drawing methods included in the map data. To reduce the drawing load and prevent the scroll processing speed from decreasing.

  Whether or not to change the drawing method is determined depending on whether or not map data having a large drawing process is drawn. For this reason, the map display apparatus 10 of the present embodiment includes a drawing time measuring unit 14 and a drawing method changing unit 19, and when the map unit is first displayed on the display unit 18 using the clock unit 16, Measure the time required for drawing. When the drawing time measured by the drawing time measuring unit 14 exceeds a predetermined threshold, it is determined that the drawing processing load during scrolling is large, and the drawing method changing unit 19 determines that the drawing method included in the map data is Among the different data, data using a drawing method with a large processing load is selected and changed to a drawing method with a low processing load, and the corresponding data is converted.

  The map data stored in the map data storage unit 12 is composed of unit map data divided by a predetermined latitude / longitude range. That is, the map data is divided into map areas in units of predetermined latitude and longitude, and is composed of mesh unit map data. When the map display device 10 moves to newly require map data, necessary unit map data is read from the map data storage unit 12.

  FIG. 2 is a diagram illustrating an example of the data configuration of the mesh unit map accumulated in the map data storage unit 12. As shown in FIG. 2, in the unit map data, the unit map mesh number and map range (latitude range, longitude range, scale) are recorded. In addition to road nodes, road links, and terrain as data types, buildings , POI, icon image, and building image data are stored.

  The road node is a node set at an intersection, a bending point, or the like of a road in the area, and is represented by a data string indicating the node number and the position (latitude / longitude) of each node. The road link indicates a road link connecting road nodes, and is represented by a link number, a vector data string indicating the link length (distance) and direction, and a link cost (distance or required time). The terrain data is data for displaying terrain such as rivers, hills, and mountains, and is represented by an element ID, latitude, longitude, and shape data string.

  There are various image drawing methods. For example, in order to display roads and buildings in three dimensions, polygon data is prepared as shape data of roads and buildings, and the drawing processing application 111 is based on the shape data. To draw. If this drawing method is applied as it is at the time of scrolling and drawing is performed, the load of drawing processing is large and the scrolling speed is reduced. When observing the map image displayed on the display unit 18, even if a road or building image is converted into a planar image and displayed, an unnatural impression is not given. Therefore, if the Borgon data is converted into planar shape data and displayed in a planar manner during the scroll process, the load of the drawing process can be reduced and the scroll speed can be prevented from being lowered.

  Accordingly, when the map image is displayed, if the drawing time measured by the drawing time measuring unit 14 exceeds a predetermined threshold, the drawing method changing unit 19 performs processing among data having different drawing methods included in the map data. Data that uses a drawing method with a large load is selected and changed to a drawing method with a low processing load to convert the corresponding data. The drawing processing application 111 draws a map image using the converted shape data. In this way, the load of the drawing process can be reduced, and the map image can be drawn without making it unnatural.

  In the map display device 10, when a departure point and a destination are set and the navigation application is activated, the navigation application searches for an optimum route from the departure point to the destination and displays it on the display unit 18 together with a map image. This route search starts from a road node at a departure point set with reference to the map data storage unit 12 and traces a road link to a destination, accumulates the link cost of the route, and finds a route with a minimum accumulated cost. This is a recommended route.

  FIG. 3 is a flowchart showing an operation procedure in the map display device 10 according to the embodiment of the present invention described above. When a user operation is performed in the process of step S101, the map display device 10 determines whether the current position display or the map search display is performed in the process of step S102. If neither the current position display nor the map search display is displayed, a process corresponding to the user operation or the like is performed, and the process returns to step S101.

  If the current position display or the map search display is selected in the determination process in step S102, the drawing process application 111 reads out the required unit map data from the map data storage unit 12 and expands the image data in the VRAM 17 in the process in step S103. The map image is displayed on the display unit 18. During this time, the drawing time measurement unit 14 uses the clock unit 16 to measure the drawing time.

  Then, it is determined whether or not the measurement of the drawing time T is completed (whether or not the drawing is completed) in the process of step S104. If the time measurement is not completed, the determination process in step S104 is repeated, and if completed, the process proceeds to the determination process in step S105. In the determination process in step S105, it is determined whether or not a scroll operation associated with a user operation (scroll operation) or movement of the current position is necessary.

  If it is determined in step S105 that scrolling is performed, the process proceeds to step S105. If it is determined that scrolling is not performed, the determination process in step S105 is repeated. When it is determined that scrolling is performed, it is determined in the process of step S106 whether the drawing time T at the time of drawing the map image in step S103 has exceeded a predetermined threshold.

  When it is determined that the drawing time T has exceeded the predetermined threshold, the drawing method changing unit 19 uses a drawing method with a large processing load among the data with different drawing methods included in the unit map data in the process of step S109. Select data and change to a drawing method with a low processing load, and convert the corresponding data. For example, an image of shape data prepared with polygon data is changed to plane shape data.

  Next, in the process of step S107, the drawing processing application 111 uses the converted shape data to develop a map image in the VRAM 17 according to the scroll amount and display it on the display unit 18. The scrolled map image does not display the image of the shape by the drawing method using the Bolgon data, but displays the shape obtained by changing the drawing method to a plane image, and the load of the scroll processing (drawing processing) is reduced accordingly. .

  On the other hand, if it is determined that the drawing time T does not exceed the predetermined threshold value, the drawing processing application 111 uses the currently displayed map data as it is in the processing of step S107 and develops a bitmap in the VRAM 17 according to the scroll amount. The scrolled map image is displayed on the display unit 18.

  When the scroll process ends, it is determined whether or not new unit map data is necessary in the determination process of step S108. If it is determined that no new unit map data is required, the process returns to the determination process in step S105 (determination process for determining whether or not scrolling has been performed).

  If it is determined in step S108 that new unit map data is necessary, the process returns to step S103, and the drawing processing application 111 reads the required unit map data from the map data storage unit 12 and stores the image data in the VRAM 17. And a map image is displayed on the display unit 18. During this time, the drawing time measurement unit 14 uses the clock unit 16 to measure the drawing time.

  As described above, according to the map display device and the map scrolling method according to the embodiment of the present invention, when the drawing time of the unit map data to be displayed exceeds a predetermined threshold, it is included in the unit map data at the time of scrolling. Select data that uses a drawing method with a large processing load from among the data with different drawing methods and change the drawing method to a drawing method with a low processing load. It will be possible to draw without unnaturalness.

  In the above embodiment, the map display device using the drawing method changing unit 19 has been described, but the function of the drawing method changing unit 19 may be provided as part of the drawing processing application 111 as a subroutine. .

It is a block diagram which shows schematic structure of the map display apparatus concerning the Example of this invention. It is a figure for demonstrating the data structure of the map data accumulate | stored in a map display apparatus. It is a figure which shows the map display procedure of the map display apparatus concerning the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Map display apparatus 11 ... Control part 12 ... Map data storage part 13 ... Operation part 14 ... Drawing time measurement part 15 ... Current position detection part 16 ... Clock part 17 ... VRAM
18... Display unit 19... Drawing method change unit

Claims (4)

A map display device that includes a map data storage unit that stores map data and a display unit, reads map data including a current position or a desired point from the map data storage unit, and displays a map image on the display unit.
The map data stored in the map data storage unit includes unit map data in which data relating to roads, terrain, buildings, and POIs in a predetermined area are accumulated according to the data type, and the map display device uses a drawing processing application. An installed control unit, a drawing time measuring unit, and a drawing method changing unit;
When the drawing processing application displays the unit map data, the drawing time measuring unit measures the drawing time, and when the drawing processing application scrolls the map image, when the drawing time exceeds a predetermined threshold, The drawing method changing unit selects data using a drawing method having a large processing load from data having different drawing methods included in the unit map data, and changes the drawing method to a drawing method having a low processing load. A map display device, wherein map data is drawn based on a drawing method changed by the drawing method changing unit and a map image displayed on the display unit is scrolled.   When the drawing time exceeds a predetermined threshold, the drawing method changing unit selects polygon data using a drawing method with a large processing load from among data having different drawing methods included in the unit map data to reduce the processing load. The map display device according to claim 1, wherein the map display device converts the drawing method by converting into small planar image data. A map scroll in a map display device that includes a map data storage unit that stores map data and a display unit, reads map data including a current position or a desired point from the map data storage unit, and displays a map image on the display unit In the method
The map data stored in the map data storage unit includes unit map data in which data relating to roads, terrain, buildings, and POIs in a predetermined area are accumulated according to the data type, and the map display device uses a drawing processing application. An installed control unit, a drawing time measuring unit, and a drawing method changing unit;
When the drawing processing application displays the unit map data, the drawing time measuring unit measures the drawing time, and when the drawing processing application scrolls the map image, the drawing time exceeds a predetermined threshold value. ,
A drawing method changing step in which the drawing method changing unit selects data using a drawing method with a large processing load from among data having different drawing methods included in the unit map data, and changes the drawing method to a drawing method with a low processing load; The drawing processing application includes a step of drawing map data based on the drawing method changed by the drawing method changing unit and scrolling the map image displayed on the display unit. .   The drawing method changing step selects a polygon data using a drawing method with a large processing load from among data having different drawing methods included in the unit map data when the time exceeds a predetermined threshold, and a plane with a small processing load. 4. The map scrolling method according to claim 3, further comprising a process of converting to image data and changing a drawing method.

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