KR100807995B1 - Hilbert space filling curve generating method and geographic information providing apparatus and system using that - Google Patents

Abstract

The present invention relates to a method and a system for generating an ultra-high order Hilbert space filling curve. The Hilbert space filling curve generating method of the present invention is a method for generating Hilbert space filling curve for providing map information. Determining the size of the; (b) generating a directional matrix composed of unit cells having the same starting and ending points of the Hilbert curve corresponding to the size of the directional matrix; (c) generating four basic grids having a starting point and an end point respectively having four directions of lower, left, right, and right sides to fill each unit cell of the directional matrix; (d) filling each unit cell of the directional matrix with a basic grid in a corresponding direction; And (e) assigning a Hilbert order according to the order of connection of the directional matrices, which is easy to provide a large amount of map information, and has the effect of generating the Hilbert curve more quickly.

GIS, LBS, Telematics, Hilbert Curves, Directional Matrix, Basic Grid

Description

Hilbert space filling curve generating method and geographic information providing apparatus and system using that}

1 is a diagram showing the basic unit of the Hilbert curve

2 is an exemplary diagram in which the Hilbert curve is applied to provide conventional map information.

3 is a flowchart illustrating a process of storing a node ID using a Hilbert curve in FIG.

4 is a flowchart illustrating a Hilbert curve generation method according to the present invention.

5 is a diagram illustrating a basic unit structure of a directional matrix

6 shows an example of a basic directional matrix.

7 shows an example of generating a directional matrix.

8 shows an example of a basic grid and an axial change grid.

9 is a diagram illustrating a Hilbert curve combining process according to the present invention.

10 is a block diagram showing an apparatus for providing map information according to the present invention;

11 is a block diagram showing a map information providing system according to the present invention

<Explanation of symbols for the main parts of the drawings>

10: main body 12: I / O interface

14: controller

16, 72: directional matrix generation module

18, 74: basic grid generation module

20, 76: Hilbert curve coupling module

22: memory means 30: display means

40: key input means 50: map information providing terminal

60: network 70: server

78: database

The present invention relates to a method and system for generating an ultra high order Hilbert space filling curve to provide map information, and more particularly, is applicable to an ultra high order Hilbert space filling curve having a very high degree of order. Hilbert space-filling curve generation method and map information providing device using the same, which is easy to provide positive map information, generates Hilbert curve more quickly, and minimizes transmission traffic when transmitting map information through the network. And the system.

In general, in the field of Geographic Information System (GIS), Location Based Services (LBS), Telematics (Telematics) applications, the road network structure should be stored when providing users with map search and route search services on the map. . The road network is stored in the form of nodes representing edges and intersections representing road sections, and each node is given an ID.

In response to a user's request for searching for map information, various methods of providing map information have been disclosed. However, the Hilbert Space Filling Curve method has been disclosed as the fastest and method for reducing the number of accesses to a database. 1 shows the basic unit of the Hilbert space filling curve, a curve disposed in the basic unit of the 2 * 2 grid as shown is called a Hilbert space filling curve or Hilbert curve 1. Conventionally, the method of generating the Hilbert curve is performed by extending the copying or symmetry of the basic unit of FIG. 1.

FIG. 2 illustrates an embodiment in which a Hilbert curve of a 4 * 4 grid is applied to map information retrieval, and shows a second-order Hilbert curve of the basic unit of FIG. 1. In FIG. 2, denoted by N1 to N9 means a node that is an intersection point of the road 2. A method of storing a node ID using the Hilbert curve of FIG. 2 is illustrated in FIG. 3. Referring to FIG. 3, first, a road is divided into a fixed grid as in FIG. 2, and then a Hilbert order is generated according to the Hilbert algorithm (ST10). Then, the Hilbert order is given to the Hilbert space overlapping the node of the road (ST20). Thereafter, the nodes are sorted in order of Hilbert order (ST30). In the example of FIG. 2, N7 = 2, N1 = 6, N6 = 7, N5 = 8, N2 = 9, N3 = 11, N4 = 12, N8 = 14, and N9 = 15. The node IDs are given in this sorted order (ST40), and then stored in the node ID order (ST50). In the example of FIG. 2, N7, N1, N6, N5, N2, N3, N4, N8, and N9 are stored in this order.

As described above, when the Hilbert curve is used, in order to search for nodes N1, N2, N5, and N6 included in the query region 3 box in FIG. 2, information of adjacent regions in the database is searched. That is, if only N1, N6, N5, and N2, which are stored in the database, are accessed, the desired map information can be retrieved, thereby reducing the number of accesses to the database.

However, in the conventional map information generation method using the Hilbert curve, the Hilbert curve is simply expanded recursively. However, road networks typically used in GIS, LBS, and telematics applications range from tens of thousands to hundreds of thousands of nodes. To store or retrieve this information using Hilbert curves, Hilbert curves of very high order must be generated. The conventional Hilbert curve generation method has a problem that it is difficult to generate more than 1000 orders of the highest order Hilbert curve. That is, in the conventional recursive Hilbert curve generation method, there are many obstacles in retrieving a large amount of map information. In addition, the higher the order, the more time is devoted to generating the Hilbert curve, which causes a time delay in searching and displaying map information in a navigation device or a GPS device. In addition, when data communication is performed through the network, there is a problem in that network transmission traffic occurs due to the burden of data transmission amount.

The present invention has been proposed to solve the above problems, and unlike the conventional method of simply generating a Hilbert curve by a recursive expansion method, by generating a directional matrix having a directional and adding a general Hilbert curve expansion method to the directional matrix By generating Hilbert curves, it is easy to generate Hilbert curves of very high order, and accordingly, Hilbert space filling curve generation method and map information providing device and system using the Hilbert curve for storing and retrieving massive map information It aims to provide.

In addition, an object of the present invention is to significantly reduce the time to generate the Hilbert curve, thereby providing a faster map information search service to the user.

Further, an object of the present invention is to prevent network transmission traffic by optimizing the data transmission amount when transmitting map information data through a network.

Hilbert space filling curve generation method of the present invention for achieving the above object, in the Hilbert space filling curve generation method for providing map information, (A) determining the size of the directional matrix; (b) generating a directional matrix composed of unit cells having the same starting and ending points of the Hilbert curve corresponding to the size of the directional matrix; (c) generating four basic grids having a starting point and an end point respectively having four directions of lower, left, right, and right sides to fill each unit cell of the directional matrix; (d) filling each unit cell of the directional matrix with a basic grid in a corresponding direction; And (e) assigning a Hilbert order in accordance with the order of connection of the directional matrices.

In this case, in step (a), the size of the directional matrix is determined by a value obtained by dividing the size of the entire grid by the size of the basic grid.

Preferably, step (b) comprises; (b-1) generating a basic directional matrix to have one of four directions of lower, left, right, and right directions; (b-2) determining whether the size of the basic directional matrix and the size of the final directional matrix to be generated determined in step (a) are the same; (b-3) expanding the base directional matrix when the size of the base directional matrix is different from the size of the directional matrix to be finally generated in step (b-2); And (b-4) storing the completed directional matrix when the size of the basic directional matrix is the same as the size of the directional matrix to be finally generated in the step (b-2).

In addition, step (c) includes; (c-1) generating a basic grid in one of four directions of lower, left, right, and right directions so that the start point and the end of the Hilbert curve have the same direction; (c-2) axially transforming the basic grid generated in the above step in three different directions to generate four basic grids; And (c-3) storing the basic grid in four directions.

A map information providing apparatus of the present invention for achieving the above object is a map information providing apparatus using a Hilbert space filling curve, the directional matrix at a predetermined ratio of the total grid size corresponding to the map information to be displayed via the display means A directional matrix generating module configured to generate a directional matrix composed of a controller for determining a size, unit cells connected to the controller and having unit cells having the same direction as a start point and an end point of a Hilbert curve corresponding to the size of the directional matrix; A basic grid generation module for generating basic grids in four directions of the top, bottom, left and right to be filled in unit cells, a Hilbert curve coupling module for coupling a basic grid of a corresponding type to each unit cell of the directional matrix and giving a Hilbert order; Display means and keys by control And an I / O interface for interfacing with the input means.

Preferably, the apparatus further comprises memory means for storing the directional matrix generated by the directional matrix generating module, the basic grid generated by the basic grid generating module, and the Hilbert order generated by the Hilbert curve combining module. .

A map information providing system of the present invention for achieving the above object is a server for providing map information using a Hilbert space filling curve, and a map information providing terminal for receiving map information from the server through a network and displaying the map information to a user. In the map information providing system comprising a directional matrix generating module for generating a directional matrix composed of unit cells having the same start and end points of the Hilbert curve corresponding to the size of the entire grid of map information to be transmitted to the server And a basic grid generation module for generating basic grids in four directions of lower, left, right, and right directions to be filled in the unit cells of the directional matrix, and a Hilbert curve combination for combining a basic grid of a corresponding type to each unit cell of the directional matrix and giving a Hilbert order. Characterized in that the module is installed.

Preferably, the server further includes a database storing a directional matrix generated by the directional matrix generating module, a base grid generated by the basic grid generating module, and a Hilbert order generated by the Hilbert curve combining module. do.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings and embodiments. 4 is a flowchart illustrating a Hilbert curve generation method according to the present invention, FIG. 5 is a diagram illustrating a basic unit structure of a directional matrix, FIG. 6 is a diagram illustrating an example of a basic directional matrix, and FIG. 7 is a diagram of a directional matrix generation. 8 is a diagram illustrating an example of a basic grid and an axial change grid, FIG. 9 is a diagram illustrating a Hilbert curve combining process according to the present invention, and FIG. 10 is an apparatus for providing map information according to the present invention. 11 is a block diagram showing a map information providing system according to the present invention.

First, the present invention relates to a method and system for generating a Hilbert space filling curve to provide map information. In an embodiment of the present invention, the present invention focuses on a process of generating a Hilbert curve and assigning a Hilbert order to the generated Hilbert curve. This will be described. Hereinafter, the "Hilbert Space Filling Curve" will be referred to as "Hilbert Curve", which is a synonym for convenience, and providing map information using the Hilbert Curve generated by the present invention may be performed by a conventional method.

The Hilbert curve generating method according to the present invention may be used to search for map information stored in a memory unit provided in a map information providing device such as a navigation device, or may be used when transmitting map information from a navigation server to a navigation terminal. .

A process of generating a Hilbert curve and assigning a Hilbert order in the apparatus and system for providing map information is shown in FIG. 4. Referring to this, first, when the map information of a predetermined area is searched or transmitted at the request of the user, the size of the entire grid corresponding to the map information is determined, and thus the size of the directional matrix is determined (ST100). The directional matrix referred to in the present invention means a matrix arranged so that the starting point and the end point of the Hilbert curve have the same direction, and the Hb curve in which the starting point and the end point of the Hilbert curve are located below is referred to as a reference direction. In the description of the four directions "lower, left, right" will be described. In step ST100, the size of the directional matrix is determined by a value obtained by dividing the total grid size corresponding to the map information by the size of the basic grid. For example, in the present embodiment, the size of the entire grid is 32 * 32 and the size of the basic grid is set to 8 * 8. Accordingly, the size of the directional matrix is determined to be 4 * 4 in step ST100. Once the size of the directional matrix is determined, a directional matrix is then generated corresponding to the size of the directional matrix. In this step, first, the basic direction of the directional matrix is set (ST110).

5 shows the basic units of the directional matrix, wherein the basic units of the directional matrix have a size of 4 * 4 grid. As such, the basic unit of the directional matrix having a size of 4 * 4 grid forms one unit cell in the entire directional matrix. The basic unit of the directional matrix is divided into the H-b unit cell at the bottom of the Hilbert curve, the H-t unit cell at the top, the H-l unit cell at the left, and the H-r unit cell at the right. The rule for generating these four unit cells is as follows. As shown in (a) of FIG. 5A, the x and y axes of the 4 * 4 grid forming the Hb unit cell are named x_b and y_b, and the maximum value of the grid is named X_MAX and Y_MAX. do. Then, when the x and y axes of the Ht unit cell shown in FIG. 5 (b) are x_t and y_t, respectively, the coordinate values of each grid in the Ht unit cell are Hb unit cell and x_t = X_MAX-x_b, y_t = The relationship of Y_MAX-y_b holds. Similarly, the x-axis and the y-axis of the H-l unit cell are x_l and y_l, respectively, and the coordinate values have a relationship of x_l = y_b and y_l = x_b. In addition, the x-axis and the y-axis of the H-r unit cells are x_r and y_r, respectively, and the coordinate values have a relational expression of x_r = X_MAX-y_b and y_r = Y_MAX-x_b.

When the basic direction of the directional matrix is set among the four directions in the lower, left, right, and right directions, a basic directional matrix is generated (ST120). For example, if the basic direction of the directional matrix is set downward in step ST110, a basic directional matrix of type H-b is generated in step ST120. 6 illustrates a basic directional matrix in four directions of lower, left, right, and right sides having a size of 4 * 4. First, the H-b type basic directional matrix is arranged such that H-b, H-b, H-r, and H-1 unit cells are located in a clockwise direction from the upper left so that the starting point and the end point of the Hilbert curve are located below. The rules in which the unit cells are arranged are the same as the rules for forming the unit cells of the aforementioned directional matrix, and the Ht, Hl and Hr type basic directional matrices shown in (b), (c) and (d) of FIG. Again, the same rules are used to arrange the unit cells of the directional matrix. The basic directional matrix thus generated has a size of 2 * 2, and then it is determined whether the size of the basic directional matrix is the same as the size of the final directional matrix determined in step ST100 (ST130). In this embodiment, since the size of the directional matrix is determined to be 4 * 4, it will be determined as NO in ST130, and then the basic directional matrix is extended (ST140).

Since the basic direction of the directional matrix is set downward, a 4 * 4 final directional matrix is generated as a 4 * 4 matrix with the start and end points of the Hilbert curve below as shown in FIG. In this way, if the directional matrix is generated 4 * 4 size, it will be determined as an example in step ST130, the completed directional matrix is stored in the memory means of the navigation device or the database of the navigation server (ST150).

Then, the basic grid is generated according to the conventional recursive Hilbert curve generation method. The basic grid is a unit of the Hilbert curve filled in each unit cell of the directional matrix, and in this embodiment, the size of the basic grid is an 8 * 8 grid. First, as shown in FIG. 8A, an H-b type basic grid is generated (ST160). In addition, since each unit cell of the directional matrix has a type of Hb, Ht, Hl, and Hr, in order to generate a base grid corresponding thereto, the base grid of the Hb type is axially transformed in step ST160 to Ht (rotating 180 degrees). Create a basic grid of type Hl (rotated 90 degrees) and Hr (rotated 270 degrees). Four basic grids each having four directions of lower, left, right, and right are stored in memory means and the like (ST170).

Next, as shown in FIG. 9, a basic grid of a corresponding type is coupled to each unit cell of the directional matrix (ST180). Coupling the base grid to each unit cell of the directional matrix may be performed by replacing each unit cell with a base grid of a corresponding type. As such, when the entire grid is completed by combining the directional matrix and the basic grid, the Hilbert order is given to each grid according to the connection order of the directional matrices in the entire grid (ST190).

10 and 11 illustrate a device and a system for providing map information to which the Hilbert curve generation method according to the present invention is applied, and with reference to this, a device and a system to which the present invention is applied are as follows.

FIG. 10 is a diagram illustrating a map information providing apparatus for providing map information using a Hilbert curve, illustrating a navigation device. The apparatus for providing map information of FIG. 10 includes a main body 10, a display means 30, and a key input means 40, and the main body 10 includes a display means 30 and a key input means 40. There is a built-in controller 14 for control of internal components, including an I / O interface 12 for interfacing. The controller 14 determines the total grid size in response to the map information to be displayed through the display means 30. For example, when the user requests the search for the map information, the virtual space in which the grid is arranged in a grid is determined by the number of nodes on the road network included in the search target area, which is an entire grid of n * n form. .

The directional matrix generation module 16 and the basic grid generation module 18 are connected to the controller 14. The directional matrix generation module 16 generates a directional matrix having a size of a predetermined ratio of the total grid size. Preferably, the size of the directional matrix is determined by dividing the total grid size by the base grid size. The directional matrix has a matrix structure formed of unit cells having the same starting point and the ending point of the Hilbert curve, and is generated by the flow described above with reference to FIG. 4. The basic grid generation module 18 generates a basic grid by copying and connecting the Hilbert curve using a conventional recursive Hilbert curve generation method. The basic grid generation module 18 first generates a basic grid of type Hb so as to have a size set at a predetermined ratio of the total grid size, and converts the basic grid of Hb type into four basic grids having four directions of lower, left, right, and right directions. Create Then, the Hilbert curve coupling module 20 connected to the directional matrix generation module 16 and the basic grid generation module 18 couples the basic grid of the type to each unit cell of the directional matrix, and according to the connection order of the directional matrix. Grant a Hilbert order. The Hilbert order thus granted is transferred to the controller 14 and stored in the memory means 22. Meanwhile, the process of generating and combining the directional matrix and the basic grid has been described above with reference to FIGS. 4 to 9.

In the present invention, providing the map information by using the Hilbert curve may be performed in the navigation server, and after providing the Hilbert order to the map information in the server, it may be provided to the map information providing terminal such as a navigation device through the network. 11 illustrates a map information providing system providing map information using a Hilbert curve. Referring to this, the map information providing terminal 50 exemplifying a navigation device mounted on a vehicle may receive map information in real time from the server 70 through the wireless network 60 or the like. At this time, the server 70 is provided with a directional matrix generation module 72, a basic grid generation module 74, a Hilbert curve coupling module 76, which is a component as described above. In addition, the map information data to be transmitted to the map information providing terminal 50 is stored in the database 78 of the server 70.

The directional matrix generation module 72 determines the size of the directional matrix according to the overall grid size corresponding to the map information to be transmitted to the map information providing terminal 50 and generates the directional matrix. The basic grid generation module 74 generates a basic grid in four directions of lower, left, right, and right to be filled in each unit cell of the directional matrix. The Hilbert curve coupling module 76 couples the basic grid and the axial transformation grid of the type to each unit cell of the directional matrix, and gives a Hilbert order according to the connection order of the directional matrix. The directional matrix, base grid, Hilbert order are all stored in the database 78.

As described above, the Hilbert curve generation method and the apparatus and system for providing map information using the same define a directional matrix of four directions in the lower, left, right, and right directions having a direction having a start point and an end point of the Hilbert curve, and separately define a basic grid of four directions. By generating and filling Hilbert order by filling each unit cell of directional matrix, when generating Hilbert curve for map information retrieval and transmission, the generation flow and time of Hilbert curve can be drastically shortened compared with the conventional recursive generation method. do. Therefore, when displaying a large amount of conventional map information, for example, map information requiring more than 1000 orders of high order Hilbert curves, it is possible to solve the problem that the Hilbert curve method does not operate normally. In addition, the navigation device can search the map information more quickly, and even when the navigation information is transmitted through the network, the amount of data can be significantly reduced to prevent network transmission traffic.

The present invention is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible within the scope without departing from the technical spirit of the present invention. It will be apparent to those who have knowledge.

As described above, the Hilbert space filling curve generation method and the map information providing apparatus and system using the same generate the Hilbert curve based on the directional information, and thus generate the Hilbert curve by a conventional recursive method. Compared to this, the generation order of the Hilbert curve can be significantly reduced, and the generation time and the amount of data of the Hilbert curve can be minimized. Therefore, it is easy to search or transmit a huge amount of map information using the Hilbert curve, so that the Hilbert curve generation method can be more actively used in the GIS, LBS, and telematics fields. In addition, when the present invention is applied to the navigation device, the user can search the map information in a very fast time, and even if the navigation server provides the map information to the terminal through the wireless network, the amount of data and the transmission time can be adjusted. This can minimize the network traffic.

Claims (8)

In the Hilbert space filling curve generation method for providing map information, (a) determining the size of the directional matrix; (b) generating a directional matrix composed of unit cells having the same starting and ending points of the Hilbert curve corresponding to the size of the directional matrix; (c) generating four basic grids having a starting point and an end point respectively having four directions of lower, left, right, and right sides to fill each unit cell of the directional matrix; (d) filling each unit cell of the directional matrix with a basic grid in a corresponding direction; And (e) Hilbert space filling curve generation method comprising the step of assigning the Hilbert order in accordance with the order of connection of the directional matrix. The method of claim 1, The method of claim 1, wherein the size of the directional matrix is determined by dividing the size of the entire grid by the size of the basic grid. The method of claim 1, Step (b) comprises; (b-1) generating a basic directional matrix to have one of four directions of lower, left, right, and right directions; (b-2) determining whether the size of the basic directional matrix and the size of the final directional matrix to be generated determined in step (a) are the same; (b-3) expanding the base directional matrix when the size of the base directional matrix is different from the size of the directional matrix to be finally generated in step (b-2); And (b-4) storing the completed directional matrix when the size of the basic directional matrix is the same as the size of the final directional matrix to be generated in the step (b-2). The method of claim 1, Step (c) comprises; (c-1) generating a basic grid in one of four directions of lower, left, right, and right directions so that the start point and the end of the Hilbert curve have the same direction; (c-2) axially transforming the basic grid generated in the above step in three different directions to generate four basic grids; And (c-3) Hilbert space filling curve generation method comprising the step of storing the basic grid in a total of four directions. In the map information providing apparatus using a Hilbert space filling curve, A controller for determining the size of the directional matrix at a predetermined ratio of the total grid size corresponding to the map information to be displayed through the display means, and connected to the controller in the same direction as the start and end points of the Hilbert curve corresponding to the size of the directional matrix. A directional matrix generating module for generating a directional matrix composed of unit cells having a basic grid, a basic grid generating module for generating a basic grid in four directions in which the unit cells of the directional matrix are filled, and a corresponding unit cell of the directional matrix; Hilbert curve coupling module for coupling the basic grid of the type and granting the Hilbert order, and an I / O interface for interfacing with the display means and the key input means under the control of the controller . The method of claim 5, And a memory means for storing the directional matrix generated by the directional matrix generating module, the basic grid generated by the basic grid generating module, and the Hilbert order generated by the Hilbert curve combining module. Map information providing device. In the map information providing system comprising a server for providing map information using a Hilbert space filling curve, and a map information providing terminal for receiving map information from the server through a network and displaying the map information to a user. The server may include a directional matrix generation module configured to generate a directional matrix composed of unit cells having the same direction as the start point and the end point of the Hilbert curve, corresponding to the size of the entire grid of map information to be transmitted, and the unit cell of the directional matrix. Map information, characterized in that the basic grid generation module for generating a basic grid of four directions in the bottom, left and right, and a Hilbert curve combining module for coupling the basic grid of the type and giving a Hilbert order to each unit cell of the directional matrix Provide system. The method of claim 7, wherein The server may further include a database storing a directional matrix generated by the directional matrix generating module, a basic grid generated by the basic grid generating module, and a Hilbert order generated by the Hilbert curve combining module. Map information providing system.

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