Map display method and device

[0055] Embodiment one

[0056] refer to figure 1 , is a flow chart of a map display method provided in Embodiment 1 of the present application. The method is applied to electronic devices such as navigation devices (such as navigators, mobile terminals (such as mobile phones) installed with navigation software), and the navigation The device includes a screen for displaying an electronic map, and the display screen may be a liquid crystal display or a touch display, and the method may include the following steps:

[0057] Step 101: Obtain the current center point of the electronic map displayed on the screen of the navigation device and the target center point of the electronic map to be displayed.

[0058] Wherein, the current center point refers to the center point of the electronic map currently displayed on the screen of the navigation device, and the target center point refers to the center point of the electronic map to be displayed on the screen of the navigation device.

[0059] Taking the navigation device as a mobile phone with navigation software installed as an example, the center point of the electronic map currently displayed on the display screen of the mobile phone is the Po point (ie, the current center point). When the user needs to switch maps, the center point of the electronic map that the user needs to view and display on the display screen of the navigation device is Pk (ie, the target center point). like figure 2 shown in .

[0060] Step 102: Select at least one intermediate point between the current center point and the target center point.

[0061] Step 103: Taking the intermediate point and the target central point as center points in turn, and displaying an electronic map on the screen of the navigation device in the order that the intermediate point and the target center point are closer to the current center point.

[0062] It should be noted that each of the intermediate points is sequentially distributed on the connecting line between the current central point and the target central point, therefore, each of the intermediate points and the target central point has a distance from the current central point The order from near to far, or, the current center point and each of the intermediate points has an order from far to near to the target center point.

[0063] Wherein, the number of the intermediate points can be set by the user, such as 12 or 24, etc., the more the number of the intermediate points, the stronger the coherence when the electronic map is subsequently displayed on the screen of the navigation device, And the corresponding calculation amount is larger.

[0064] It should be noted that, in the step 103, the following can also be implemented: taking the intermediate point and the target center point as the center points in turn, according to the distance between the intermediate point and the target center point and the target center point from near to far In sequence, an electronic map is displayed on the screen of the navigation device. This implementation method is the same as the above, with the intermediate point and the target central point as the center point in turn, and according to the sequence of distance from the intermediate point and the target center point to the current center point, the electronic display on the screen of the navigation device The manner of the map belongs to the same idea and will not be described in detail here.

[0065] It can be seen from the above scheme that the map display method provided by Embodiment 1 of the present application obtains the current center point of the electronic map displayed on the screen of the navigation device and the target center point of the electronic map to be displayed, and then displays the current center point and the target center point between the current center point and the target center point. Select the middle point among the points, and then take the middle point and the target center point as the center point in turn, and display the electronic map on the screen of the navigation device in the order of the distance between the middle point and the target middle point and the current center point. Application purpose. Embodiment 1 of the present application realizes the switching display between maps corresponding to two points, by selecting a plurality of points between the two points as intermediate points, and then displaying the electronic maps corresponding to these intermediate points in sequence to achieve multiple intermediate points The purpose of the coherent display of the map is to make the switching process of the electronic map similar to the coherent animation display, and the user's eyes do not need to refocus to a large extent to adapt to the picture, reducing the user's visual fatigue and improving the user experience.

[0066] Embodiment two

[0067] Compared with the map display method provided in Embodiment 1, the map display method provided in Embodiment 2 of the present application has figure 1 Step 102 in the flow chart shown is refined. refer to image 3 , is a flow chart of step 102, wherein said step 102 can be specifically implemented through the following steps:

[0068] Step 121: Determine the distance between the current center point and the target center point.

[0069] Step 122: Determine whether the distance is greater than a preset distance threshold, and when the distance is greater than the distance threshold, perform step 123; otherwise, perform step 125.

[0070] Step 123: On the connection line between the current center point and the target center point, select a third center point whose distance from the current center point is equal to the distance threshold, and perform step 124.

[0071] Step 124: Taking the current center point as a starting point, select at least one intermediate point from the line connecting the current center point and the third center point according to a preset distance.

[0072] Step 125: Taking the current center point as a starting point, select at least one intermediate point from the line connecting the current center point and the target center point according to a preset distance.

[0073] In the embodiment of the present invention, if the coordinates of the current center point, the target center point, and the intermediate point are screen coordinates obtained by transforming geographic latitude and longitude coordinates, the distance between the current center point and the target center point calculated in step 121 is the screen distance, then the embodiment of the present invention sets the distance threshold as half of the diagonal length of the screen of the navigation device. If the coordinates of the current center point, the target center point, and the intermediate point are geographic latitude and longitude coordinates, the distance between the current center point and the target center point calculated in step 121 is the distance between the current center point and the target center point. If the actual distance between the navigation devices is the actual distance, the distance threshold is the half of the diagonal length of the screen of the navigation device, which is converted according to the scale of the electronic map.

[0074] It should be noted that when the distance calculated in step 121 is greater than the distance threshold, it indicates that the target center point of the electronic map to be displayed is outside the current display content of the electronic map displayed on the screen of the navigation device. , it can be referred to as long-distance switching, thus, in step 123, a third center point is selected on the line between the current center point and the target center point, and then step 124 is executed, starting from the current center point, from On the line between the current center point and the third center point, at least one intermediate point is selected, thus, in the subsequent step 103, the intermediate point and the target center point can be used as the center point in turn, according to the intermediate point and the target center The electronic maps corresponding to each intermediate point and the target center point are displayed on the screen of the navigation device in order of distance from the current center point in descending order.

[0075] like Figure 4 As shown, on the connection line between the current center point Po and the target center point Pk, the third center point Pc is selected.

[0076] It should be noted that when the distance calculated in step 121 is less than or equal to the distance threshold, it indicates that the target center point of the electronic map to be displayed currently is within the current display content of the electronic map displayed on the screen of the navigation device , at this time, it can be referred to as short-distance switching, thus, in the step 125, starting from the current center point, at least one intermediate point is selected every preset interval distance on the line connecting the current center point and the target center point . From the subsequent step 103, the intermediate point and the target center point can be used as the center point in turn, and the screen display of the navigation device can be displayed in the order of the distance between the intermediate point and the target center point from the current center point. Electronic maps corresponding to each intermediate point and target center point.

[0077] It should be noted that, in each of the above-mentioned implementation embodiments, when the electronic maps corresponding to the intermediate points and the target center points are displayed on the screen of the navigation device in the step 103, with the existing computing power and data transmission speed The improvement of the azimuth makes the acquisition and display of the electronic maps corresponding to the intermediate points and the target central points extremely fast, and the time required to display the multiple intermediate electronic maps is relatively short, which may not be able to provide users with a coherent display effect. Therefore, in order to further improve the effect of coherently displaying the electronic map, the embodiment of the present invention presets a time interval, such as 20 milliseconds or 40 milliseconds. In step 103, the specific implementation is as follows: according to the order in which the intermediate point and the target center are closer to the current center point, a corresponding cached electronic map is displayed on the screen of the navigation device at every preset time interval superior. The embodiment of the present invention does not strictly limit the value of the time interval, which can be flexibly set as required. Preferably, in order to further meet the needs of different users, the time interval can be set by the user, and the time interval set by the user can be used as the preset time interval. For example, young users with good eyesight can set the time interval to 20 milliseconds, and users with poor eyesight can set the time interval to 40 milliseconds.

[0078] Embodiment three

[0079] In practical applications, in order to improve the acquisition and coherent display rate of the electronic map corresponding to the intermediate point and the target center point, the electronic map corresponding to each intermediate point and the target center point can be pre-drawn and cached, and displayed on the screen of the navigation device. When the intermediate point and the target center point are the electronic maps of the center point, the corresponding electronic map is directly obtained from the cache and displayed on the screen of the navigation device. Compared with the foregoing embodiment one and embodiment two, the difference between this embodiment three is that figure 1 Step 103 in the flow shown is refined. Therefore, refer to Figure 5 , is a flowchart of step 103, wherein said step 103 may include the following steps:

[0080] Step 131: Obtain the map data cached when generating the electronic map with the current center point as the center point.

[0081] It should be noted that, when the navigation device displays its current electronic map on its screen, it needs to acquire map data for drawing an electronic map with the current center point as the center point from the map database, and cache the acquired map data. And the geographic range covered by the acquired map data is larger than the geographic range covered by the electronic map with the current center point as the center point.

[0082] Step 132: According to the order of distance from each intermediate point to the current center point, according to the coordinates of each intermediate point and the screen size of the navigation device, from the cached map data, copy the center point of the electronic map with each intermediate point And the image covering the geographical area corresponding to the screen size of the navigation device is used as an electronic map with the corresponding intermediate point as the center point, and the electronic map is cached.

[0083] Step 133: Obtain map data centered on the target center point, generate an electronic map centered on the target center point according to the acquired map data, and cache the electronic map.

[0084] Step 134: Display the corresponding cached electronic map on the screen of the navigation device according to the order of the distance between each intermediate point and the target center point from the current center point.

[0085] Preferably, in step 134, it is implemented in the following manner: according to the order of the intermediate point and the target center from the current center point in order of distance from the current center point, a cached corresponding electronic map is displayed on the on the screen of the navigation device. The preset time interval can be dynamically set, for example, according to the actual situation of the user of the current navigation device. For example, a young user with better eyesight can set the interval to 20 milliseconds, and an elderly user with poor eyesight can set the interval. The time length is 40 milliseconds, etc., so as to better realize the coherent switching display between the corresponding electronic maps of each intermediate point and the target center point, which is more similar to the coherent animation display, and the user's eyes do not need to refocus multiple times to adapt to the screen. Reduce user visual fatigue and improve user experience.

[0086] The technical solution provided by Embodiment 3 of the present invention, on the one hand, since the electronic map with each intermediate point as the center point is generated, directly from the cached map data, copy the center point of the electronic map with each intermediate point as the center point and cover the geographical range and The image corresponding to the screen size of the navigation device is used as an electronic map with the corresponding intermediate point as the center point, without obtaining map data for drawing an electronic map with each intermediate point as the center point from the map database, and then according to the acquired Therefore, the technical solution provided by Embodiment 3 of the present invention can obtain an electronic map with the middle point as the center point very quickly and efficiently. On the other hand, after obtaining the electronic map with the intermediate point and the target center point as the center point, the electronic map is cached, and when the electronic map is subsequently displayed, the corresponding electronic map is directly obtained from the cache and displayed, which can further speed up Electronic map display speed.

[0087] In order to facilitate those skilled in the art to understand the technical solution of the present invention, the specific implementation of the technical solution of the present invention will be described in more detail below with a specific example:

[0088] a) Obtain the center point of the electronic map displayed before switching (ie the current center point) and the center point of the electronic map after switching (ie the target center point) as P0 and Pk, where P0 and Pk are screen coordinates.

[0089] b) Calculate the screen distance between P0 and Pk as D.

[0090] c) Judging whether D is greater than the preset distance threshold X (X=d/2, where d is the length of the diagonal of the screen of the navigation device), if D is less than or equal to X, it is judged as short-distance switching, according to the following d ) method; otherwise, it is a long-distance handover, and it is processed according to the method e) below.

[0091] d) Short-distance switching: Calculate the screen displacement {DX, DY} of the line connecting P0 and Pk, where DX=(Xk-X0), DY=(Yk-Y0); divide {DX, DY} into n parts to obtain {dx=DX÷n, dy=DY÷n}, where n is the number of intermediate points plus 1. Every preset time interval t, the electronic map on the display screen of the navigation device is moved {dx, dy}. A total of n times of movement takes time T=t×n and total displacement {DX, DY} to switch the center point to the target center point Pk, and display an electronic map with Pk as the center point on the screen of the navigation device. Since the displacement {dx, dy} of each switching change is small, the map switching appears more coherent. Coherence is related to P0, Pk distance and n value. Since the distance from P0 to Pk is relatively short, the first n shifted images can be drawn using the rendering cache to improve display efficiency. like Image 6 As shown in , it is the change process of the area displayed in the window of the screen of the navigation device during the short-distance switching process.

[0092] e) Long-distance switching: take Pc on the connection line of P0 and Pk, Pc={Xc, Yc}, the distance from Pc to P0 is equal to X, and calculate the screen displacement {FX, FY} of the connection line of P0 and Pc, DX=(Xc-X0), DY=(Yc-Y0); Divide {FX, FY} into n parts to get {dx=FX÷n, dy=FY÷n}, where n is the number of intermediate points plus 1 . Every time interval t, move the window image by {dx, dy}. A total of n times of movement takes time T=t×n and total displacement {FX, FY} to switch the center point to the target center point Pk, and display an electronic map with Pk as the center point on the screen of the navigation device. Although the displacement from Pc to Pk is relatively large, the coherent display of the electronic map from P0 to Pc makes the overall display of the electronic map more coherent. like Figure 7 As shown in , it is the change process of the area displayed in the window of the navigation device screen during the long-distance switching process.