JP2006235113A - Map display device, map switching method, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continuously change and display a map image in zoom-in and zoom-out operations of changing the scale of the map image. <P>SOLUTION: A map display device 1 which includes a picture display part and is capable of continuously changing the display magnification of the map image displayed on the picture display part includes; a determination and acquisition means which determines a map image having a scale different from that of the map image being displayed on the picture display part, which corresponds to the map image being displayed, in a process of changing the display magnification of the map image being displayed and acquires the map image having the different scale; and a switching and display means which switches the map image being displayed to the map image having the different scale, which has been acquired by the acquisition means, in response to arrival at a predetermined display magnification of the display magnification of the map image being displayed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for continuously enlarging or reducing a map image displayed on a display of a computer.

  As a site that allows a plurality of map images with different scales to be displayed on a user terminal, use http: // www. mapion. co. jp / (Mapion) or http: // www. mapfan. com / (map fan). In these sites, you can search for an address, select a station, display a map image around the target location, display a map image at a different scale around the displayed map image, A map image translated left and right can be displayed.

In addition, there exists what was described in patent document 1 as one of the prior arts regarding continuously enlarging and reducing a map image.
JP 2002-055601 A

  In the conventional technology provided on the above sites, when a map image is enlarged or reduced by performing a zoom-in / zoom-out operation on a user terminal, a map having a scale different from the scale of the map image currently focused on is used. The image is simply switched to the current map image.

  Therefore, when the scale ratio of the map image before and after switching is large, the change in the map image is large. Therefore, there is a problem that it is difficult to grasp the position or the like focused on the map image before switching in the map image after switching.

  The present invention has been made in view of the above points, and an object thereof is to provide a technique for continuously changing and displaying a map image in a zoom-in / zoom-out operation for changing the scale of the map image.

  The above-described problem is a map display device that includes a screen display unit and can continuously change the display magnification of the map image displayed on the screen display unit, and the map image being displayed on the screen display unit In the process of changing the display magnification of the map, the determination and acquisition of determining a map image having a scale different from the scale of the map image being displayed corresponding to the map image being displayed and acquiring the map image having a different scale And a map image of a different scale acquired by the acquisition unit is switched with the map image being displayed, when the display magnification of the map image being displayed reaches a predetermined display magnification. This can be solved by a map display device characterized by comprising switching display means for displaying the image.

  In the map display device described above, each scale map image is composed of a plurality of unit map images, and the determination acquisition unit is configured so that the units of the different scales corresponding to the predetermined positions in the screen of the screen display unit. A map image can be determined, unit map images around the unit map image can be determined, and these unit map images can be acquired.

  The switching display means uses the scale of the map image being displayed, the scale of the map image of the different scale, and the display magnification of the map image being displayed, and the map image of the different scale to be switched. Display magnification can be determined.

  Moreover, this invention can also be comprised as a map switching method which the said map display apparatus performs. The present invention can also be configured as a program that causes a computer to realize the functions of the map display device, and a computer-readable recording medium that records the program.

  According to the present invention, a map image having a different scale is acquired in the process of changing the display magnification of the map image being displayed, and the acquisition is performed when the display magnification reaches a predetermined display magnification. Since the stored map image is displayed, it is possible to continuously change and display the map image in the zoom-in / zoom-out operation.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram according to an embodiment of the present invention. As shown in FIG. 1, the system of the present embodiment has a configuration in which a map display device 1 and a map providing device 2 are connected by a network 3.

  FIG. 2A shows a functional configuration example of the map display device 1. As shown in FIG. 2A, the map display device 1 includes a screen display unit 11, a movement operation information acquisition unit 12, a map image display control unit 13, a map image front display unit 14, a map image back display unit 15, a map The image acquisition unit 16, the map image configuration information storage unit 17, the front cache storage unit 18, and the back cache storage unit 19 are provided.

  FIG. 2B shows a functional configuration example of the map providing device 2. As shown in FIG. 2B, the map providing device 2 includes a map image distribution unit 21 and a map image storage unit 22.

  Each of the map display device 1 and the map providing device 2 is a computer having a CPU, a memory, a hard disk (storage device), a network communication device, a display, an input device such as a mouse and a keyboard, and the like. This can be realized by installing a program for realizing the above. The program can be provided by being stored in a recording medium such as a CD-ROM or an electronic memory, or can be distributed via a network.

  In addition, although this Embodiment demonstrates the form from which the map display apparatus 1 and the map provision apparatus 2 were isolate | separated, the map provision apparatus 2 is not used by providing the map display apparatus 1 with the map image storage part 22. FIG. It can also be configured. In the configuration of FIG. 2, the map image configuration information storage unit 17 can be provided in an apparatus outside the map display device 1.

(System operation overview)
The outline of the operation in the system of the present embodiment will be described below. In the present specification and claims, the “scale” of the map is used in a general sense. That is, “increasing the scale” means reducing the denominator X when the scale is 1 / X, and “decreasing the scale” is when the scale is 1 / X. It is to increase X. Further, the “enlargement rate” is a real number equal to or greater than 0, and if the “enlargement rate” is less than 1, the image is actually reduced. However, an enlargement ratio of less than 1 may be referred to as a “reduction ratio”. In the claims, “enlargement ratio” or “reduction ratio” is referred to as “display magnification”.

  In the above system, when the user performs a zoom-in operation (enlarges the map) on the map image displayed on the screen display unit 11 (display) of the map display device 1, the map display device 1 displays the screen. While the map image displayed on the unit 11 is enlarged, a map image having a larger scale than the current map image is acquired from the map providing device 2. Then, an enlargement ratio is calculated based on a scale ratio between the acquired map image and the currently displayed map image, and the acquired map image is enlarged or reduced according to the calculated enlargement ratio, and the current map image and Switch to display.

  Further, when the user performs a zoom-out operation (reducing the map), the map image displayed on the screen display unit 11 is reduced, while a map image having a smaller scale than the current map image is provided. Obtained from device 2. Then, the enlargement ratio is calculated based on the scale ratio between the acquired map image and the currently displayed map image, and the acquired map image is enlarged or reduced according to the calculated enlargement ratio, and switched to the current map image. To display.

  Through the processing as described above, the scale of the map image can be continuously changed in the zoom-in and zoom-out operations in the map display device 1.

(System operation details)
Next, the processing operation of the system of the present embodiment will be described in more detail. Before describing the operation, first, referring to FIG. 3 for the hierarchical structure of map images of different scales used in the present embodiment. I will explain.

  In the example of FIG. 3, the map image with the scale A is the map image with the map image ID A1-1 to A3-3, the map image with the scale B is the map image with the map image ID B1-1 to B6-6, Map images with map image IDs C1-1 to C12-12 are shown as map images with a scale C. Here, the relationship from scale A to scale C is scale A <scale B <scale C. For example, the actual geographical length next to the map image A1-1 on the scale A is 100 km, the horizontal length on the map image B1-1 on the scale B is 50 km, and the map image C1-1 on the scale C is next to the map image C1-1. The length is 25 km, and A1-1, B1-1, and C1-1 are the same size as the map image. That is, when the map image A1-1 and the map image C1-1 are displayed on the same size screen, the map image A1-1 covers a wider area than the map image C1-1, but the map image C1-1. The map can be displayed in more detail than the map image A1-1.

  In the present specification and claims, a map image of a smaller scale as viewed from a map image of a certain scale is called an upper scale, and a map image of a larger scale as viewed from a map image of a certain scale is referred to as a lower scale. Call. That is, in FIG. 3, the upper scale is the one above the scale of interest, and the lower scale is the one below. In FIG. 3, the shaded A1-1 map image of the scale A corresponds to an image of the scale B B1-1, B1-2, B2-1, B2-2 represented by the scale A. . Other map images have the same relationship.

  Next, information stored in each storage unit and used in processing operations described below will be described.

  The map image configuration information storage unit 17 of the map display device 1 stores the map image configuration information shown in FIG. As shown in FIG. 4, the map image configuration information includes a map image ID for each map image, a map image ID of the map image located on the left of the map image, and a map image ID of the map image located on the map image. The map image ID of the map image located to the right of the map image, the map image ID of the map image located below the map image, and the upper scale map image ID of the map image.

  The front cache storage unit 18 stores the map image ID of the map image that the map image front display unit 14 is arranging in the memory. The back cache storage unit 19 stores the map image ID of the map image on which the map image back display unit 15 is arranged. Further, the map image data arranged in the map image front display unit 14 and the map image back display unit 15 are also stored in the front cache storage unit 18 and the back cache storage unit 19. In the map image storage unit 22 of the map providing device 2, all map images are stored in association with IDs.

  The map image front display unit 14 and the map image back display unit 15 virtually arrange the screen on the memory, and a part of the screen arranged on the memory is actually displayed on the screen display unit 11. Is done.

(Operation when zooming in)
Next, in accordance with the flowchart of FIG. 5, a zoom-in operation is performed, and the map image displayed on the screen display unit 11 of the map display device 1 is enlarged, and a map image at a lower scale is acquired and switched and displayed. Processing will be described.

  Step 0) First, the number N of map images to be arranged at one time on the map display device 1, the size of the screen, the center coordinates of the screen, and the zoom-in operation of the map image are magnified to obtain the next map image. The maximum enlargement ratio Z indicating the switching timing and the size of the map image to be used are set. These values may be input manually, or values stored in advance in the storage device of the map display device 1 may be read out.

  The size of the screen is the size of the screen that displays the map in the screen display unit 11 (display) of the map display device 1 and is represented by the number of horizontal x vertical dots. The size of the map image to be used is the size of one map image (a map image corresponding to one ID), which is also represented by the number of horizontal x vertical dots.

  In this embodiment, the number of map images to be used at one time is 9, the screen size is 800 × 600, the center coordinates of the screen are (400, 300), and the maximum magnification rate for switching to the next map image in the zoom-in operation is 2 The size of the map image to be used is 800 × 600.

  Step 1) The front cache storage 18 stores the map image IDs of nine map images that are currently displayed (A1-1, A1-2, A1-3, A2-1, A2- shown in FIG. 6). 2, A2-3, A3-1, A3-2, A3-3) and a map image are stored, and the map image front display unit 14 stores the map image ID stored in the front cache storage unit 18. The map image corresponding to is acquired and arranged in the memory.

  FIG. 7 shows image contents arranged by the map image front display unit 14. As shown in FIG. 7, the map image front display unit 14 arranges nine map images arranged in a grid pattern (with map image IDs A1-1, A1-2, A1-3, A2-1). , A2-2, A2-3, A3-1, A3-2, A3-3). It is assumed that the area surrounded by the dotted line in FIG. 7 is actually displayed on the screen display unit 11, and a screen display example at that time is shown in FIG.

  A map image is displayed in the left area of FIG. 8, and a zoom controller for zooming in / out on the map image is displayed on the right side. In the example of FIG. 8, clicking on the upper arrow A with a mouse or the like zooms in, and clicking on the lower arrow B zooms out. In addition, it is assumed that the map display device 1 is configured to continuously zoom in and zoom out by continuously pressing a button such as a mouse.

  Step 2) When the user of the map display device 1 starts clicking the button A of the zoom controller in Step 2 of FIG. 5, the movement operation information acquisition unit 12 acquires the movement operation start information for zooming in, and starts the movement operation. Information is transmitted to the map image display control unit 13.

  Step 3) Subsequently, in step 3, when the map image display control unit 13 receives the movement operation start information, the map image display control unit 13 transmits the movement operation start information to the map image front display unit 14. When the map image front display unit 14 receives the moving operation start information, the map image front display unit 14 displays the map image at the center point of the screen in the map image currently displayed on the screen of the image display unit 11. The map image ID is calculated, and the map image ID, the upper left coordinates of the map image, and the enlargement ratio of the current map image are transmitted to the map image display control unit 13.

  In the example of this embodiment shown in FIGS. 7 and 8, the map image ID at the center point of the screen is A1-1 at the start of the zoom-in operation, and the upper left coordinates of A1-1 are (−100, −100). The map image enlargement rate at the start of the click operation is assumed to be 1.2, and the map image front display unit 14 transmits these values to the map image display control unit 13.

  Step 4) In step 4 of FIG. 5, the map image front display unit 14 enlarges the map image displayed on the screen of the screen display unit 11. If the enlargement ratio is less than or equal to the maximum enlargement ratio set in step 0, enlargement is repeated. It is assumed that the user keeps pressing the button A of the zoom controller. An example of the enlarged screen is shown in FIG.

  Further, when the map image is enlarged and the enlargement ratio reaches 2 or more, the map image front display unit 14 sends a display end request notification to the map image display control unit 13, and the map image display control unit 13 enlarges the map image. The map image is continuously enlarged until an end notification is received. Note that the enlargement end notification is a notification indicating that it is ready to display a lower-scale map image, as will be described later. When the enlargement end notification is received from the map image display control unit, the enlargement of the current map image is ended.

  Step 5-1) On the other hand, after the processing of Step 3, in Step 5-1, the map image display control unit 13 sends the map image ID (A1-1) and the coordinates in the upper left screen from the map image front display unit 14 ( -100, -100) and an enlargement ratio of 1.2, the map image display control unit 13 performs a process of determining a lower-scale map image corresponding to the acquired map image ID (A1-1).

  In this process, first, the number of divisions is obtained using the following equation.

Number of divisions = scale of the lower-scale map image of the notified map image / scale of the notified map image Here, in the present embodiment, the scale of A1-1 is 1/100, and the scale of the lower-scale image is 1/50 and the number of divisions is 2. And the vertical and horizontal of the map image of A1-1 are each divided into two, and the map image is divided into four. FIG. 10 shows an example of dividing the map image A1-1.

  Next, among the four divided map images, the position (any one of the four) of the map image at the lower scale located at the center of the screen displayed by the screen display unit 11 is obtained. In the present embodiment, the notified map image ID is A1-1, the upper left coordinate of the map image is (−100, −100), the enlargement ratio is 1.2 times, the screen size is 800 × 600, Since the center coordinate is (400, 300) and the size of the map image to be used is 800 × 600, it is as shown in FIG. 11 (note that the scale shown in FIG. 11 is not necessarily accurate) and is located at the center of the screen. It can be seen that the position of the map image at the lower scale is the lower right of the four divided map images.

  As another example, the notified map image is A2-2, the upper left coordinate of the map image is (200, 100), the obtained enlargement ratio is double, and the screen size set in step 0 is 1000. When × 800, the center coordinates of the screen are (500,400), and the size of the map image to be used is 800 × 600, the map is as shown in FIG. 12. In this case, the lower scale map corresponding to A2-2 is used. In the image, it can be seen that the map image located at the upper left is in the center of the screen.

  Subsequently, the map image display control unit 13 accesses the map image configuration information storage unit 17 based on the map image ID A1-1 received from the map image front display unit 14, and the map image of A1-1. Is searched for a map image ID having an upper scale. As partly shown in FIG. 4, the map images having A1-1 as the upper image are B1-1, B1-2, B2-1, and B2-2. The positional relationship among B1-1, B1-2, B2-1, and B2-2 is as shown in FIG. B2-2 which is a map image on the lower right is selected from these lower scale images.

  Subsequently, the map image display control unit 13 extracts all the map image IDs adjacent to the selected B2-2, and transmits all the extracted map image IDs to the map image acquisition unit 16. As shown in FIG. 14, the map images adjacent to B2-2 are B1-1, B1-2, B1-3, B2-1, B2-2, B2-3, B3-1, B3-2, B3. Therefore, the map image display control unit 13 transmits these map image IDs to the map image acquisition unit 16.

  Step 5-2) Subsequently, when the map image acquisition unit 16 acquires the map image ID in Step 5-2 of FIG. 5, the map image ID is transmitted to the map image distribution unit 21 of the map providing device 2. . The map image distribution unit 21 accesses the map image storage unit 22 based on the received map image ID, acquires the corresponding map image, and transmits the map image to the map image acquisition unit 16 of the map display device 1. Then, the map image acquisition unit 16 stores the received map image and map image ID in the back cache storage unit 19. After the acquisition of all requested maps is completed, a map image acquisition end notification is transmitted to the map image display control unit 13.

  Note that the zoom-in operation from the user continues while the processing in steps 5-1 and 5-2 is performed, and the screen is enlarged based on the processing in step 4.

  After the acquisition of the lower scale map image is completed and the map image display control unit 13 receives the display end request notification from the map image front display unit 14, the process proceeds to step 6.

  Step 6) In Step 6, the map image display control unit 13 transmits an information acquisition request to the map image front display unit 14, and the map image front display unit 14 that has received the information acquisition request, as shown in FIG. The map image ID (A1-1) previously transmitted to the image display control unit 13, the current upper left coordinates of the map image (referred to as (-200, -200)), and the enlargement ratio (doubled) ) To the map image display control unit 13.

  The map image display control unit 13 that has received the information transmits the information to the map image back display unit 15.

  When receiving the above information, the map image back display unit 15 reads all the map images stored in the back cache storage unit 19. Then, the read map image is enlarged or reduced based on the received information, and is arranged at an appropriate coordinate position using the current upper left coordinates (-200, -200) of A1-1. The arrangement is performed with reference to the map image configuration information as necessary.

  Here, the enlargement ratio when enlarging or reducing is calculated using the following equation.

Magnification ratio of map image to be arranged = received magnification ratio × scale of currently displayed map image / scale of lower scale map image In this embodiment, the magnification ratio of map image to be arranged = 2 × 50/100 = 1. It is.

  In the present embodiment in the state shown in FIG. 15, the lower scale map images (B1-1, B1-2, B1-3, B2-) read from the back cache storage unit 19 and arranged by the map image back display unit 15 are arranged. 1, B2-2, B2-3, B3-1, B3-2, B3-3) and the positional relationship between the map image to be displayed on the screen display unit 11 are as shown in FIG.

  After the map image back display unit 15 arranges the lower scale map image, the map image back display unit 15 notifies the map image display control unit 13 of display start.

  Step 7) In step 7, when the map image display control unit 13 receives the display start notification from the map image back display unit 15, the map image display control unit 13 transmits an enlargement end notification to the map image front display unit 14, and the map image front display unit 14 receives the enlargement end notification, ends the enlargement of the currently displayed screen and hides the map image, and the map image back display unit 15 displays the screen.

  After that, the map image back display unit 15 and the back cache storage unit 19 function as the map image front display unit 14 and the front cache storage unit 18 described so far, and the map image front display unit 14 and the front cache storage unit 18. However, it functions as the map image back display unit 15 and the back cache storage unit 19 described so far. Therefore, even when the user continues to zoom in, it is possible to display a screen that is continuously enlarged by displaying a lower scale screen by the procedure as described above.

(Operation when zooming out)
Next, in the system configuration shown in FIGS. 1 and 2, a process of reducing the scale of the map image displayed on the screen in accordance with the zoom-out operation of the user, acquiring a map image of a higher scale, and switching and displaying the map image Will be described with reference to the flowchart of FIG. Here, the maximum number of map images to be displayed on the map display device 1 at one time, the size of the screen, the center coordinates of the screen, and the maximum reduction ratio indicating the timing of reducing the map image and switching to the next map image. It is assumed that Z (assumed to be 0.8 here) and the size of the map image to be used are set. Further, as shown in FIG. 18, the front cache storage unit 18 has B2-2, B2-3, B2-4, B3-2, B3-3, B3-4, B4-2, B4-3, B4-. 4 is stored, the map image front display unit 14 arranges the map image as shown in FIG. 19 in the memory, and the screen display unit 11 displays the map image within the bold line in FIG. .

  Step 11) In response to the user starting to click B of the zoom controller of the screen display unit 11 in Step 11 of FIG. 17, the movement operation information acquisition unit 12 acquires zoom-out movement operation start information and moves. The operation information acquisition unit 12 transmits the movement operation start information to the map image display control unit 13.

  Step 12) When the map image display control unit 13 receives the movement operation start information in Step 12, the map image display control unit 13 transmits the movement operation start information to the map image front display unit 14, and the map image front display unit 14 When the movement operation start information is received, the map image ID at the center point of the screen is calculated in the map image currently displayed on the screen display unit 11, and the map image ID is transmitted to the map image display control unit 13. . Here, as shown in FIG. 19, B <b> 3-3 is transmitted to the map image display control unit 13.

  Step 13) In step 13, the map image front display unit 14 reduces the map image displayed on the screen in accordance with the user's operation of the zoom controller. If the reduction ratio is greater than or equal to the preset minimum reduction ratio of 0.8, the reduction is repeated. An example of the screen display when reduced is shown in FIG. The dotted line in FIG. 20 is a portion displayed on the screen display unit 11. When the map image is reduced and the reduction ratio becomes 0.8 or less, a display end request notification is sent from the map image front display unit 14 to the map image display control unit 13, and a reduction end notification is sent from the map image display control unit 13. Continue to reduce the map image until it comes. Further, when a reduction end notification is received from the map image display control unit 13, the reduction of the currently displayed screen is stopped.

  Step 14-1) On the other hand, following Step 12 of FIG. 17, in Step 14-1, the map image display control unit 13 receives the map image ID (B3-3) from the map image front display unit 14. Next, in the upper scale map image to which the acquired map image ID belongs, the map image ID of the map image located at the center point portion of the screen is acquired. When acquiring, the map image display control unit 13 accesses the map image configuration information storage unit 17 based on B3-3 received from the map image front display unit 14, and the upper scale map image ID corresponding to B3-3. To extract. In FIG. 4, the upper scale map image corresponding to B3-3 is A2-2.

  Next, all the adjacent map image IDs are extracted from the determined map image ID of the higher scale, and all the extracted map image IDs are transmitted to the map image acquisition unit 16. Since the map image adjacent to A2-2 becomes A1-1, A1-2, A1-3, A2-1, A2-3, A3-1, A3-2, and A3-3 as shown in FIG. These and A2-2 are transmitted to the map image acquisition unit 16.

  Step 14-2) When the map image acquisition unit 16 acquires the map image ID in step 14-2, the map image ID is transmitted to the map image distribution unit 21 of the map providing device 2. The map image distribution unit 21 accesses the map image storage unit 22 based on the received map image ID, acquires the corresponding map image, and transmits the map image to the map image acquisition unit 16 of the map display device 1.

  The map image acquisition unit 16 stores the received map image and map image ID in the back cache storage unit 19, and transmits a map image acquisition end notification to the map image display control unit 13 when the map image acquisition unit 16 ends.

  After the map image display control unit 13 receives the acquisition end notification and receives the display end request notification from the map image front display unit 14, the process proceeds to step 15.

  Step 15) The map image display control unit 13 transmits an information acquisition request to the map image front display unit 14. The map image front display unit 14 transmits to the map image display control unit 13 the map ID (B3-3) previously transmitted to the map image display control unit 13 and the current upper left coordinates and reduction ratio of the map image. . Here, it is assumed that the current state is as shown in FIG. 22, and B3-3, the upper left coordinates (200, 100) of B3-3, and a reduction ratio of 0.8 are transmitted.

  When the map image back display unit 15 receives the map image ID (B3-3), the coordinates, and the reduction rate, the map image back display unit 15 reads all the map images in the back cache storage unit 19. Then, the read map image is appropriately enlarged or reduced, and the read map image is arranged in the memory using the fact that the upper left coordinate of B3-3 is (200, 100). At this time, placement is performed with reference to the map image configuration information as necessary.

  The enlargement ratio when appropriately enlarging or reducing is determined using the following equation.

Magnification rate of map image to be arranged = Received reduction rate × Scale of currently displayed map image / Scale of upper scale image In this embodiment, the magnification rate of map image to be arranged = 0.8 × 100/50 = 1.6. An example of a screen arranged by the map image back display unit 15 is shown in FIG.

  Step 17) After this arrangement, a display start notification is sent to the map image display control unit 13, and when the map image display control unit 13 receives the display start notification from the map image back display unit 15, the map image front display unit 14 When the reduction end notification is transmitted and the map image front display unit 14 receives the reduction end notification, the map image front display unit 14 ends the reduction and hides the current map image. And the part of a screen area | region is displayed among the screens which the map image back display part 15 has arrange | positioned.

  As described above, according to the system according to the present embodiment, before and after switching of map images in the zoom-in / out operation, the map images with different scales, such as the magnification rate and position, are continuously displayed. Is possible.

  The present invention is not limited to the above-described embodiment, and various modifications and applications can be made within the scope of the claims.

It is a system configuration figure in an embodiment of the invention. It is a figure which shows the function structure of the map display apparatus 1 and the map provision apparatus 2. FIG. It is a figure which shows the hierarchical structure of the map image of a different scale. It is a figure which shows map image structure information. It is a process flowchart in the case of zoom-in operation. It is a figure which shows map image cache information. It is a figure which shows the image content which the map image front display part 14 arrange | positions. It is a figure which shows the example of a screen display. It is a figure which shows an example of the enlarged screen. It is a figure which shows the example which divided | segmented the map image of A1-1. It is a figure which shows the position of the map image of the lower scale located in the center of a screen. It is a figure which shows the position of the map image of the lower scale located in the center of a screen. It is a figure which shows the map image of a lower scale. It is a figure which shows the map image adjacent to B2-2. It is a figure which shows the current upper left coordinate and magnification of a map image. It is a figure which shows the positional relationship of a lower scale map image and the map image which will be displayed on the screen display part. It is a process flowchart in the case of zoom-out operation. It is a figure which shows map image cache information. It is a figure for demonstrating the image in the map image front display part. It is a figure which shows the example of the screen display at the time of reducing. It is a figure which shows the map image adjacent to A2-2. It is a figure which shows the current upper left coordinate and reduction ratio of a map image. It is an example of a screen which the map image back display part 15 arrange | positions.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Map display apparatus 2 Map providing apparatus 3 Network 11 Screen display part 12 Movement operation information acquisition part 13 Map image display control part 14 Map image front display part 15 Map image back display part 16 Map image acquisition part 17 Map image structure information storage part 18 Front cache storage unit 19 Back cache storage unit 21 Map image distribution unit 22 Map image storage unit

Claims (8)

A map display device comprising a screen display unit and capable of continuously changing the display magnification of a map image displayed on the screen display unit,
In the process of changing the display magnification of the map image being displayed on the screen display unit, a map image having a scale different from the scale of the map image being displayed corresponding to the map image being displayed is determined, Decision acquisition means for acquiring map images of different scales;
When the display magnification of the map image being displayed has reached a predetermined display magnification, the map image of a different scale acquired by the acquisition means is displayed by switching to the map image being displayed. Switching display means;
A map display device characterized by comprising:   Each scale map image is composed of a plurality of unit map images, and the determination acquisition means determines the unit map images of different scales corresponding to predetermined positions in the screen of the screen display unit, and The map display device according to claim 1, wherein unit map images around the unit map image are determined, and these unit map images are acquired.   The switching display means displays the map image of the different scale to be switched using the scale of the map image being displayed, the scale of the map image of the different scale, and the display magnification of the map image being displayed. The map display device according to claim 1, wherein a magnification is determined. A map switching method executed by a map display device that includes a screen display unit and is capable of continuously changing a display magnification of a map image displayed on the screen display unit,
In the process of changing the display magnification of the map image being displayed on the screen display unit, a map image having a scale different from the scale of the map image being displayed corresponding to the map image being displayed is determined, A decision acquisition step for acquiring map images of different scales;
When the display magnification of the map image being displayed has reached a predetermined display magnification, the map image at a different scale acquired in the acquisition step is displayed by switching to the map image being displayed. A switching display step;
A map switching method characterized by comprising:   Each scale map image is composed of a plurality of unit map images, and in the determination and acquisition step, the map display device uses the unit map of the different scale corresponding to a predetermined position in the screen of the screen display unit. The map switching method according to claim 4, wherein an image is determined, unit map images around the unit map image are determined, and these unit map images are acquired.   In the switching display step, the map display device uses the scale of the map image being displayed, the scale of the map image of the different scale, and the display magnification of the map image being displayed, and the different map to be switched. The map switching method according to claim 4, wherein a display magnification of the reduced scale map image is determined. A program comprising a screen display unit, causing a computer to realize a function as a map display device capable of continuously changing the display magnification of a map image displayed on the screen display unit, the computer comprising:
In the process of changing the display magnification of the map image being displayed on the screen display unit, a map image having a scale different from the scale of the map image being displayed corresponding to the map image being displayed is determined, Decision acquisition means for acquiring map images of different scales;
When the display magnification of the map image being displayed has reached a predetermined display magnification, the map image of a different scale acquired by the acquisition means is displayed by switching to the map image being displayed. Switching display means,
Program to function as.   A computer-readable recording medium storing the program according to claim 7.

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