Patent Publication Number: US-2007124065-A1

Title: Map transmission system and method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims the priority benefit of Taiwan application serial no. 94141571, filed on Nov. 25, 2005. All disclosure of the Taiwan application is incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a map transmission system and a method thereof. More particularly, the present invention relates to a map transmission system which converts a map into a vector map data to be transmitted and a method thereof.  
      2. Description of Related Art  
      Along with the rapid development of telecommunication technology, electronic apparatus with global positioning system (GPS), such as mobile phone, personal digital assistant (PDA), or navigation device, has become an indispensable consumer product in our daily life because of its real-time navigation function.  
      Presently, an electronic apparatus with GPS usually has screenshot function for capturing part of the map, and then the electronic apparatus transmits the part of the map to another electronic apparatus via the Internet, so as to exchange the map information. In conventional technique, the captured map is mapped to a corresponding space in a virtual raster image, and each raster is filled up with color pixels so as to form the entire image, and the captured map is transmitted in an image file format such as graphics interchange format (GIF), joint photographic experts group (JPEG), or windows bit map (BMP). The received map cannot be zoomed randomly if the image quality is not good enough. By enlarging the map, the size of each pixel raster is increased accordingly, thus the definition of the image is reduced. Moreover, when a map is transmitted, a lot of information is contained in a compressed map to enable it decompressing to the original image file, thus, the quantity of data to be transmitted is very large, and which increases the transmission time.  
      Accordingly, a map transmission system and a method thereof are provided in the present invention for resolving the problems described above.  
     SUMMARY OF THE INVENTION  
      Accordingly, the present invention is directed to provide a map transmission system and a method thereof, wherein a map to be transmitted is converted into a vector map data so that the quantity of data to be transmitted is reduced and accordingly the map can be transmitted quickly.  
      To achieve the aforementioned objective, the map transmission system in the present invention includes a database, a sender, and a receiver. Wherein, the database stores at least one map data. The sender generates a map frame data based on the map to be transmitted and converts the map frame data into a vector map data through the database, and then the sender transmits the vector map data to a remote site via a network. The receiver receives the vector map data and displays the vector map data by using a map engine application program.  
      As described above, the map transmission method in the present invention includes the following steps. First, a database is set to store at least one map data. Then, a sender is provided to generate a map frame data based on the map to be transmitted and to convert the map frame data into a vector map data through the database, and then the sender is directed to transmit the vector map data to a remote site via a network. Finally, a receiver is provided to receive the vector map data and to display the vector map data by using a map engine application program. Accordingly, the purpose of reducing the time of transmitting the map is accomplished.  
      In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, a preferred embodiment accompanied with figures is described in detail below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.  
       FIG. 1  is a diagram of a map transmission system in the present invention.  
       FIG. 2  is a diagram of an electronic apparatus in the present invention.  
       FIG. 3  is a flowchart illustrating the map transmission method of the sender according to an embodiment of the present invention.  
       FIG. 4  is a flowchart illustrating the map transmission method of the receiver according to an embodiment of the present invention.  
       FIG. 5  is a diagram illustrating the format of the vector map data according to an embodiment of the present invention.  
       FIG. 6  is a diagram illustrating the format of the layer content data according to an embodiment of the present invention.  
       FIG. 7  is a diagram illustrating the format of the layer code content data according to an embodiment of the present invention. 
    
    
     DESCRIPTION OF EMBODIMENTS  
      A map transmission system and a method thereof according to exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to the like elements throughout.  
       FIG. 1  is a diagram of a map transmission system in the present invention. Referring to  FIG. 1 , the system includes a database  11 , a sender  12 , a receiver  13 , and a network  14 . The database  11  stores at least one map data. The sender  12  is set on an electronic device, such as a personal digital assistant (PDA), a navigation device, or a mobile phone with global positioning system (GPS). The sender  12  generates a map frame data based on the map to be transmitted and converts the map frame data into a vector map data through the database  11 , and then the sender  12  transmits the vector map data to the receiver  13  via the network  14 . The receiver  13  is set on another electronic device, such as a personal digital assistant (PDA), a navigation device, or a mobile phone with global positioning system (GPS). The receiver  13 . receives the vector map data and displays the vector map data by using a map engine application program. Accordingly, the quantity of data to be transmitted can be reduced and the purpose of reducing the time of transmitting the map can be accomplished.  
       FIG. 2  is a diagram of an electronic apparatus applicable to the map transmission system in the present invention. Referring to  FIG. 2 , the electronic apparatus includes an input unit  21 , a capture unit  22 , a transmission unit  23 , and a processor  24 . The input unit  21  is used for inputting a map to be transmitted. The capture unit  22  generates a map frame data based on the map. The transmission unit  23  is connected to the network  14  wirelessly to transmit/receive a vector map data to/from a remote site. The processor  24  converts a map frame data into the vector map data through the database  11  or displays the received vector map data by using a map engine application program. Besides, the electronic apparatus of the sender or the receiver may be a personal digital assistant (PDA), a navigation device, or a mobile phone. The map frame data contains, for example, the coordinates of the top left corner and the bottom right corner of the map. The vector map data is transmitted in a packet and complies with hypertext transmission protocol (HTTP) or simple mail transfer protocol (SMTP). Moreover, with the format of the vector map data, the received map can be resized randomly without losing the definition of the map.  
       FIG. 3  is a flowchart illustrating the map transmission method of the sender according to an embodiment of the present invention. Referring to  FIG. 3 , the method includes the following steps: 
          step S 310 : start;     step S 320 : a user selecting the map to be transmitted by using the input unit of the sender;     step S 330 : the capture unit generating a map frame data based on the map;     step S 340 : the processor converting the map frame data into a vector map data through the database;     step S 350 : the transmission unit transmitting the vector map data to the receiver via a network; and     step S 360 : end.        
       FIG. 4  is a flowchart illustrating the map transmission method of the receiver according to the present invention. Referring to  FIG. 4 , the method includes the following steps:  
      step S 410 : start;  
      step S 420 : the transmission unit receiving the vector map data;  
      step S 430 : the processor displaying the vector map data by using a map engine application program; step S 440 : end.  
      In addition, the map transmission system divides the map into a plurality of equal layers according to x-axis and y-axis to reduce the data quantity thereof. The vector map data contains data of these layers.  
       FIG. 5  is a diagram illustrating the format of a vector map data according to an embodiment of the present invention, wherein the map is divided into 6 layers. Referring to  FIG. 5 , the vector map data format contains a total layer number  51 , layer reference numbers  52 , layer addresses  53 , and layer content data  54 .  
       FIG. 6  is a diagram illustrating another format of a layer content data according to an embodiment of the present invention. With the content data  541  of layer 1 as an example, the layer content data contains a layer reference number  61 , a shape  62 , a layer length  63 , and a total number  64 , starting addresses  65 , lengths  66 , and content data  67  of layer codes. Besides, the content data of the other layers, such as layer 2, all have the same format.  
       FIG. 7  is a diagram illustrating another format of a layer code content data according to an embodiment of the present invention. With the content data  671  of layer code 1 as an example, the layer code content data format contains a layer code reference number  71  and a property code starting address  72 , a property code length  73 , property code content data  74 , an identity code starting address  75 , an identity code length  76 , and identity code content data  77  of the layer code. In addition, the content data of each layer code have the same format. Thus, when the receiver receives the vector map data, the receiver obtains a map in a vector image format according to the foregoing content by using a map engine application program. Accordingly, the purpose of reducing the time of transmitting a map can be accomplished.  
      It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.