[0029] In response to the problems of the prior art, the inventor provided a map display method and a device for controlling the map display, which can take any point on the screen as the current parking space position, and after changing the current parking space position, based on the original parking space The screen coordinates of the (map base point), the coordinate offset parameters of the map coordinates of the map object relative to the map coordinates of the map base point, and the transformation parameters determined according to the map rotation angle and the map scale factor convert the map coordinates of the map object into the corresponding Screen coordinates, so that the navigation map can be redrawn faster, saving computing resources in the navigation device.
[0030] In order to make the above-mentioned objectives, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0031] In the following description, specific details are set forth in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.
[0032] Such as figure 2 What is shown is a schematic flowchart of a specific implementation of a map display method of the present invention. reference figure 2 , The map display method includes:
[0033] Step S1: Obtain the screen coordinates and map coordinates of the base point of the map;
[0034] Step S2: Determine the rotation angle of the map;
[0035] Step S3: Determine transformation parameters based on the rotation angle of the map and the map scale coefficient;
[0036] Step S4: Determine the coordinate offset parameter of the map coordinates of the map object relative to the map coordinates of the map base point;
[0037] Step S5: Convert the map coordinates of the map object into the screen coordinates of the corresponding map object based on the screen coordinates of the map base point, the coordinate offset parameter, and the transformation parameter;
[0038] Step S6: Display a map containing the map object on the screen based on the screen coordinates of the map object.
[0039] The following describes in conjunction with specific embodiments figure 2 The specific implementation of the map display method. Combined reference Figure 3a with Figure 3b The effect diagram of a specific embodiment of a map display method of the present invention is shown. It should be noted that, in this embodiment, the map is a navigation map, and the navigation object is a car.
[0040] Specifically, as described in step S1, the screen coordinates and map coordinates of the base point of the map are acquired.
[0041] In this embodiment, as Figure 3a Shown is the rendering of the navigation map with the current parking space at position 2 on the screen as the center point. figure 1 The location 2 where the current parking space is located is used as the base point of the map, and it also includes multiple roads and multiple points of interest (for example, point of interest A).
[0042] Those skilled in the art know that the position 2 (that is, the base point of the map) has two coordinate values, which are screen coordinates and map coordinates, respectively. Among them, such as Figure 3a As shown, the screen coordinate system takes the upper left corner as the origin O, the X axis to the right as the positive direction, and the Y axis as the positive direction; the map coordinate system (not shown) takes the lower left corner as the origin and the X axis as the right In the positive direction, the Y-axis upward is the positive direction.
[0043] Usually in the map database of the navigation device, the coordinates of each element point on the navigation map (ie, map coordinates) are determined. Assuming that the map coordinates of location 2 (ie, the base point of the map) include latitude coordinates and longitude coordinates, the navigation is usually The device needs to convert the GPS coordinates (including latitude and longitude coordinates) acquired through the GPS receiver into Gaussian plane coordinates to achieve the correct matching of GPS coordinates in the navigation map. In this embodiment, the longitude coordinates and the latitude coordinates respectively correspond to the abscissas. mapBaseX and ordinate mapBaseY. When the navigation map needs to be displayed on the screen, the map coordinates of each element point on the navigation map need to be converted into screen coordinates. The common practice of those skilled in the art is that the basic idea of “similarity ratio” described in the prior art is The map coordinates are converted to screen coordinates, so I won’t repeat them here.
[0044] In this embodiment, it is assumed that the coordinates of the upper left corner of the screen (that is, the origin O) are (left, top) and the coordinates of the lower right corner are (right, bottom), so that the size of the screen can be determined: the length is (right-left) and the width is ( bottom-top) rectangle. Therefore, the screen coordinates of the location 2 (ie the base point of the map) can be determined in two ways:
[0045] 1) Assuming that the distance between the coordinates of position 2 and the upper left corner is dx and dy, the screen coordinates of the map base point are: scrBaseX (abscissa)=left+dx, scrBaseY (ordinate)=top+dy.
[0046] 2) Assuming that the distance between the coordinates of the position 2 and the lower right corner is dx' and dy', the screen coordinates of the map base point are: scrBaseX (abscissa)=right-dx', scrBaseY (ordinate)=bottom-dy.
[0047] Those skilled in the art can arbitrarily choose any of the above methods to determine the screen coordinates of the base point of the map.
[0048] As described in step S2, the rotation angle of the map is determined.
[0049] Those skilled in the art know that usually on the screen of the navigation device, the direction of the current parking space (such as the position 2) is always upright, which can facilitate the user to observe the position of the current parking space. However, the direction of each road in the navigation route is not necessarily upright. Therefore, during driving, if the direction of the road where the current parking space is located is not upright, you need to rotate the map so that the direction of the road where the current parking space is located is vertical. Straight up, so that all the feature points on the navigation map will have a rotation angle. The specific value of the rotation angle is determined according to the angle between the road where the current parking space is turned and the road where it was previously.
[0050] As described in step S3, the transformation parameters are determined based on the rotation angle of the map and the map scale coefficient.
[0051] In this embodiment, this step includes:
[0052] First, calculate the sine and cosine of the rotation angle.
[0053] Assuming that the rotation angle is a, the sine value of the rotation angle is: sin(a)=m_sinAngle; the cosine value of the rotation angle is: cos(a)=m_cosAngle. Further, let the scale factor of the current map be scalVal.
[0054] Then, the first transformation parameter is determined according to the ratio of the sine value and the map scale coefficient.
[0055] Specifically, the first transformation parameter is: m_sinDivScale=m_sinAngle/scalVal.
[0056] The second transformation parameter is determined according to the ratio of the cosine value and the map scale coefficient.
[0057] Specifically, the second transformation parameter is: m_cosDivScale=m_cosAngle/scalVal.
[0058] The above-mentioned first transformation parameter and second transformation parameter will be used in the subsequent conversion between map coordinates and screen coordinates.
[0059] As described in step S4, the coordinate offset parameter of the map coordinates of the map object relative to the map coordinates of the map base point is determined.
[0060] Specifically, the premise of this step is that the user changes the position on the screen where the current parking space is located, such as changing the current parking space from Figure 3a Position 2 in moved to Figure 3b In the position 2', the navigation device can directly obtain the screen coordinates of the position 2'.
[0061] Further, as Figure 3b As shown, the navigation location needs to be determined figure 1 The screen coordinates of each other feature point in ’. In this step, first determine the coordinate offset parameter of the map coordinates of the map object (including each element point) relative to the map coordinates of the map base point. For example, in the navigation figure 1 Take the point of interest B in 'as an example, suppose the map coordinates of the point of interest B (map object) include longitude coordinates and latitude coordinates, which correspond to the abscissa mapX and the ordinate mapY respectively.
[0062] This step specifically includes:
[0063] 1) Determine the abscissa offset in the coordinate offset parameter according to the longitude coordinates of the map coordinates of the map base point and the longitude coordinates of the map coordinates of the map object.
[0064] Specifically, the longitude coordinates of the map coordinates of the map base point correspond to the abscissa of mapBaseX, and the longitude coordinates of the map coordinates of the map object correspond to the abscissa of mapX. Therefore, the abscissa in the coordinate offset parameter The offset is offsetX=mapX-mapBaseX.
[0065] 2) Determine the ordinate offset in the coordinate offset parameter according to the latitude coordinates of the map coordinates of the map base point and the latitude coordinates of the map coordinates of the map object.
[0066] Specifically, the latitude coordinate of the map coordinate of the map base point corresponds to mapBaseY, and the latitude coordinate of the map coordinate of the map object corresponds to mapY. Therefore, the ordinate in the coordinate offset parameter The offset is offsetY=mapY-mapBaseY.
[0067] As described in step S5, the map coordinates of the map object are converted into the screen coordinates of the corresponding map object based on the screen coordinates of the map base point, the coordinate offset parameter, and the transformation parameter.
[0068] In this embodiment, this step specifically includes:
[0069] 1) According to the abscissa of the screen coordinates of the map base point, the product of the abscissa offset and the second transformation parameter, and the product of the ordinate offset and the first transformation parameter, the The abscissa of the map coordinates of the map object is converted into the abscissa of the screen coordinates of the map object.
[0070] Specifically, the abscissa of the screen coordinates of the map base point is scrBaseX, the abscissa offset is offsetX, the ordinate offset is offsetY, the first transformation parameter is m_sinDivScale, and the second The transformation parameter is m_cosDivScale. Therefore, the abscissa of the screen coordinates of the map object is:
[0071] scrX=scrBaseX+(offsetX*m_cosDivScale-offsetY*m_sinDivScale).
[0072] 2) According to the ordinate of the screen coordinates of the map base point, the product of the ordinate offset and the second transformation parameter, and the product of the abscissa offset and the first transformation parameter, the The ordinate of the map coordinates of the map object is converted into the ordinate of the screen coordinates of the map object.
[0073] Specifically, the ordinate of the screen coordinates of the map base point is scrBaseY, the abscissa offset is offsetX, the ordinate offset is offsetY, the first transformation parameter is m_sinDivScale, and the second The transformation parameter is m_cosDivScale. Therefore, the ordinate of the screen coordinates of the map object is:
[0074] scrY=scrBaseY-(offsetY*m_cosDivScale+offsetX*m_sinDivScale).
[0075] The above is the navigation figure 1 Take the point of interest B in 'as an example, the map coordinates of the point of interest B are converted into screen coordinates. Similarly, other map objects can also convert the map coordinates into screen coordinates according to the above method.
[0076] As described in step S6, the map containing the map object is displayed on the screen based on the screen coordinates of the map object.
[0077] Specifically, such as Figure 3b As shown, the navigation location with the position 2’ as the current parking space is displayed on the screen figure 1 ’. The navigation point figure 1 The screen coordinates of each element point (map object) in 'can be calculated according to the above step S5. Further, since in the screen coordinate system, the difference (including the abscissa difference and the ordinate difference) obtained by subtracting the screen coordinates of the origin O from the screen coordinates of each map object is a positive value, so when the above steps The difference obtained by subtracting the screen coordinates of the origin O from the screen coordinates of the map object calculated in S5 is a negative value, which means that the map object is moved out of the screen range during the map movement.
[0078] For example, continue reference Figure 3a , In the navigation location with the location 2 as the current parking space (as the base point of the map) figure 1 Point of interest A in is located within the current screen range, but in Figure 3b , In the navigation area with the position 2’ as the current parking space figure 1 In', the point of interest A has been moved out of the screen range. That is to say, the difference obtained by subtracting the screen coordinates of the origin O from the screen coordinates converted from the map coordinates of the point of interest A is a negative value. figure 1 The point of interest A is not included in the screen range of ’.
[0079] For another example, continue to refer to Figure 3b , In the navigation area with the position 2’ as the current parking space figure 1 ’Contains Figure 3a Navigation point figure 1 The point of interest B that is not included in the, is in the navigation location with the position 2'as the current parking space figure 1 In', the point of interest B is moved into the screen range. That is to say, the difference obtained by converting the map coordinates of the point of interest B into the screen coordinates minus the screen coordinates of the origin O is a positive value, and the screen coordinates are within the screen range, that is, the point of interest B The screen coordinates of is within the range of the screen size determined in step S1.
[0080] Combined reference Figure 3a with Figure 3b , The user changes the location of the current parking space from Figure 3a Position 2 in moved to Figure 3b In the position 2’, you can see more road information in the upper right corner of the current parking space. According to the map display method provided by the embodiment of the present invention, the user can use any point on the screen as the location of the current parking space, so that the observation range and the observation angle on the navigation map can be adjusted as needed. Further, the map display method according to the present technical solution can save computing resources in the navigation device.
[0081] Based on the foregoing map display method, an embodiment of the present invention also provides a device for controlling map display. Such as Figure 4 Shown is a schematic structural diagram of a specific embodiment of a device for controlling map display of the present invention. reference Figure 4 The device 3 for controlling map display includes: a coordinate acquisition unit 31 for acquiring the screen coordinates and map coordinates of the map base point; an angle determination unit 32 for determining the rotation angle of the map; a transformation parameter determination unit 33 for acquiring The rotation angle of the map determined by the angle determining unit 32 and the map scale coefficient determine the transformation parameters; the offset parameter determining unit 34 is used to determine the map coordinates of the map object relative to the map coordinates of the map base point acquired by the coordinate acquiring unit 31 The coordinate offset parameter; the coordinate conversion unit 35 is configured to determine based on the screen coordinates of the map base point acquired by the coordinate acquisition unit 31, the coordinate offset parameter determined by the offset parameter determination unit 34, and the transformation parameter unit 33 The transformation parameters of the map object convert the map coordinates of the map object into the screen coordinates of the corresponding map object; and the drawing unit 36 is configured to display the map containing the map on the screen based on the screen coordinates of the map object determined by the coordinate conversion unit 35 The map of the object. In this embodiment, the map is a navigation map, and the navigation object is a car.
[0082] Specifically, the transformation parameter determination unit 33 includes: a calculation unit (not shown) for determining the sine and cosine values of the rotation angle; a first transformation parameter determination unit (not shown) for determining the The ratio of the sine value and the map scale factor determines a first transformation parameter; a second transformation parameter determination unit (not shown) is configured to determine a second transformation parameter according to the ratio of the cosine value and the map scale factor .
[0083] The map coordinates of the map object and the map coordinates of the map base point both include latitude coordinates and longitude coordinates. The offset parameter determining unit 34 includes: a first offset parameter determining unit (not shown), configured to determine the longitude coordinates of the map coordinates of the map base point and the map coordinates of the map object. The abscissa offset in the coordinate offset parameter; a second offset parameter determination unit (not shown) for determining according to the latitude coordinates of the map coordinates of the map base point and the latitude coordinates of the map coordinates of the map object The ordinate offset in the coordinate offset parameter.
[0084] The screen coordinates of the map base point and the screen coordinates of the map object both include abscissa and ordinate. The coordinate conversion unit 35 includes: a first conversion unit (not shown), which is used to calculate the abscissa of the screen coordinates of the map base point, the product of the abscissa offset and the second conversion parameter, and The product of the ordinate offset and the first transformation parameter converts the abscissa of the map coordinates of the map object into the abscissa of the screen coordinates of the map object; a second conversion unit (not shown) uses According to the ordinate of the screen coordinates of the map base point, the product of the ordinate offset and the second transformation parameter, and the product of the ordinate offset and the first transformation parameter, the map The ordinate of the map coordinates of the object is converted into the ordinate of the screen coordinates of the map object.
[0085] Further, an embodiment of the present invention also provides a navigation device, including such as Figure 4 Shown is a device for controlling map display.
[0086] In summary, according to the map display method provided by this technical solution, any point on the screen can be used as the location of the current parking space, and after the current parking position is changed, based on the screen coordinates of the original parking space (map base point) and the location of the map object The coordinate offset parameters of the map coordinates relative to the map coordinates of the map base point and the transformation parameters determined according to the map rotation angle and the map scale factor convert the map coordinates of the map object into the corresponding screen coordinates, so that the navigation can be redrawn faster Maps save computing resources in the navigation device.
[0087] Although the present invention has been disclosed as above in preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can use the methods and technical content disclosed above to improve the present invention without departing from the spirit and scope of the present invention. The technical solution makes possible changes and modifications. Therefore, all simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention belong to the technical solution of the present invention. protected range.
