Geographic element gridding representation method suitable for ship traffic management system

Abstract

The invention discloses a geographic element gridding representation method suitable for a ship traffic management system, which combines the characteristics of the ship traffic management system to carry out fine grid division on an overwater area, converts geographic elements into information taking geographic grids as basic units through high-performance operation, and adopts a double-layer grid compression storage strategy to store the geographic elements. Therefore, the system can realize real-time high-speed access and processing of geographic information under low resource consumption. According to the method, a double-layer grid compression storage strategy is adopted for the geographic elements, real-time high-performance calling and querying of the geographic elements under the condition of low resource consumption of the VTS system are achieved, and the method has the advantages of being low in resource consumption, high in real-time performance, high in flexibility and the like.

Description

Technical Field

[0001] The invention relates to the field of information system data storage, and in particular to a geographic element gridding representation method suitable for a ship traffic management system. Background Art

[0002] The Vessel Traffic Management System (VTS) is mainly responsible for supervising the dynamics of ships in the waters and ensuring navigation safety. Its regulatory environment is characterized by a highly active economy, intensive cargo throughput, a large number of traffic participants, and severe risks of collision and pollution, which places extremely high demands on the real-time and accuracy of the system. As the core system for water safety supervision, VTS integrates a variety of data to accurately display the water traffic situation, but in the face of the current situation of a large number of targets and rapid dynamic updates, especially when using high-frequency data sources such as shore-based radar (updated every three seconds), how to instantly obtain the detailed geographic attributes of each target's location has become a major technical bottleneck. Although the existing VTS system is embedded in the S57 nautical chart, it is limited by query efficiency and mainly serves data browsing rather than real-time processing and integration, which limits the dynamic application efficiency of geographic element data.

[0003] The design of S57 charts focuses on data storage and exchange rather than fast query and display, which prompts chart suppliers to develop personalized SENC (chart system manufacturer private format) to optimize display performance. These customized solutions vary from manufacturer to manufacturer. Although they improve display efficiency, when a large number of targets need to query their location in real time, they need to process a large number of irregular points, lines, and surface elements in the charts. In particular, more than 100 layers of different types of geographic elements are spread across the VTS monitoring area, which generally exceeds 50 square kilometers. The computational intensity of traditional spatial algorithms is extremely high and cannot meet real-time computing needs. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a grid representation method of geographical elements applicable to a ship traffic management system in view of the deficiencies of the above-mentioned prior art. The grid representation method of geographical elements applicable to a ship traffic management system implements grid segmentation of geographical space, and uses pre-calculation technology to store spatial attribute information in a grid framework, and then combines efficient index grids and local map grid compression storage strategies to achieve rapid positioning and access when querying geographical attribute information of a ship target position, greatly reducing the burden of complex geometric operations, thereby breaking through the application barriers of geographical elements in real-time operations of a VTS system. The present invention has the characteristics of low resource consumption, high real-time performance, and strong flexibility.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for gridding representation of geographic elements applicable to a vessel traffic management system comprises the following steps.

[0007] Step 1: Construct a global map grid: Determine the geographic space covered by the vessel traffic management system, calculate the longitude and latitude boundaries, and construct a global basic spatial map; then divide the global basic spatial map evenly into several small grids to form a global map grid; the side length of each small grid in the longitude and latitude directions is one ten-thousandth of a degree.

[0008] Step 2: Calculate the grid geographic attributes, including the following steps:

[0009] Step 2-1, set geographic elements: the user sets the type of geographic elements to be concerned about in the VTS system.

[0010] Step 2-2, extracting regional information: first, according to the geographic spatial scope and longitude and latitude boundaries determined in step 1, retrieve the electronic nautical chart data source with equal longitude and latitude boundaries; then extract the regional information of each geographic element type from the electronic nautical chart data source.

[0011] Step 2-3, calculate geographic attributes: For each area extracted in step 2-2, use the fast projection algorithm to determine its mapping in the global map grid, so as to calculate the geographic element type of each small grid, and then form a geographic element map grid set.

[0012] Step 3: Hierarchical compression and storage, including the following steps:

[0013] Step 3-1, dividing the index grid: the geographic element map grid set formed in step 2 is evenly divided into a number of square index grids; each index grid includes b×b ​​small grids; where b>10.

[0014] Step 3-2: Hierarchical compression and storage: Traverse the small grids in each index grid in turn, and perform hierarchical compression and storage according to the following method:

[0015] A. When the geographic attributes of all small grids in the index grid are the same, the b×b small grids are merged and compressed into a single index grid.

[0016] B. When a small grid in an index grid has two or more geographic attributes, the current index grid is a multi-attribute index grid and cannot be compressed.

[0017] Step 3-3, construct a two-dimensional array of global index grids: Based on the traversal results of step 3-2, and by classifying and assigning values ​​to single index grids and multi-attribute index grids, a two-dimensional array of global index grids containing all index grids is constructed.

[0018] Step 3-4, construct a two-dimensional array of local map grids: According to the position and number of the multi-attribute index grids in step 3-3 and the set of geographic feature map grids in step 2, construct a two-dimensional array of local map grids; wherein the two-dimensional array of local map grids includes the geographic attributes of each small grid in all multi-attribute index grids.

[0019] Step 4: Rapid retrieval of geographic attributes: Based on the location of the target to be queried, locate the relevant global index grid two-dimensional array and the local map grid two-dimensional array, and extract the geographic attribute information of the target location in a timely manner.

[0020] In step 1, the method for constructing the global map grid includes the following steps:

[0021] Step 1-1, determine the geographic space scope covered by the vessel traffic management system, and calculate its longitude and latitude boundaries; the longitude and latitude boundaries include the upper longitude boundary, the lower longitude boundary, the upper latitude boundary and the lower latitude boundary.

[0022] Step 1-2, construct the global basic space boundary: the coordinates of the upper boundary of longitude and latitude are both integerized, and the coordinates of the lower boundary of longitude and latitude are both integerized, so as to form an adjusted global basic space map.

[0023] Step 1-3, divide into small grids: divide the global basic spatial map evenly into several small grids to form a global map grid; the side length of each small grid in the longitude and latitude directions is one ten-thousandth of a degree.

[0024] In step 2-3, the method of mapping each area in the global map grid using a fast projection algorithm includes the following steps:

[0025] Step 2-3A, constructing a boundary point set: For each area extracted in step 2-2, the area boundary is refined. The specific refinement method is: points are evenly selected on the boundary line of each area at an interval of less than a meters to form a boundary point set; where a is less than the minimum recognition accuracy of the ship radar.

[0026] Step 2-3B, generate a boundary map grid list: for each boundary point of each area, determine the small grid number to which it belongs on the global basic space map, thereby generating a boundary map grid list for the corresponding area.

[0027] Step 2-3C, constructing a regional coverage map grid set: by means of horizontal scanning and vertical scanning methods, respectively calculating the map grids covered by each regional boundary line, forming two independent horizontal regional coverage map grid sets and vertical regional coverage map grid sets.

[0028] Step 2-3D, build a precise coverage map grid set: compare the horizontal area coverage map grid set and the vertical area coverage map grid set, and directly include the small grids with consistent comparison results into the precise coverage map grid set; for each small grid with inconsistent comparison results, perform spatial relationship operations and include the small grids located in the corresponding area into the precise coverage map grid set.

[0029] Step 2-3E, repeat step 2-3A to step 2-3D to complete the precise coverage map grid sets of all regions in turn; then merge and summarize the precise coverage map grid sets of all regions to finally obtain a complete geographic element map grid set.

[0030] In step 2-3A, a=10 meters.

[0031] Step 3-1, b=100.

[0032] In step 3-3, the method for constructing the index grid two-dimensional array includes the following steps:

[0033] Step 3-3A, geographic feature type assignment: assign a positive integer to each geographic feature type in step 2-1.

[0034] Step 3-3B, single index grid assignment: query the geographic feature type assignment of each single index grid, and then multiply the queried geographic feature type assignment by -1 to obtain the element assignment of each single index grid.

[0035] Step 3-3C, multi-attribute index grid assignment: Assume that the initial code value of each multi-attribute index grid is 0, and assign non-negative values ​​to the elements of all multi-attribute index grids traversed in step 3-2 in ascending order.

[0036] Step 3-3D, construct a two-dimensional array of index grids: According to the order of the index grids divided in step 3-1, for each index grid, the corresponding index grid is assigned according to the method of step 3-3B or step 3-3C, thereby obtaining a two-dimensional array of global index grids after the assignment.

[0037] Step 3-4, a method for constructing a two-dimensional array of local map grids, comprising the following steps:

[0038] Step 3-4A, construct a two-dimensional array of blank local map grids: Assume that the total number of multi-attribute index grids in step 3-3 is N, then construct a two-dimensional array of blank local map grids with b rows and b×N columns.

[0039] Step 3-4B, geographic attribute assignment: traverse the geographic attribute values ​​of the small grids in each multi-attribute index grid in the geographic element map grid set, and copy them to the corresponding positions of the blank local map grid two-dimensional array, thereby forming a local map grid two-dimensional array with geographic attribute values.

[0040] In step 4, the method for quickly retrieving geographic attributes includes the following steps:

[0041] Step 4-1, position query: According to the latitude and longitude position information of the target to be queried, determine the element position in the two-dimensional array of the global index grid.

[0042] Step 4-2, read element value: read the element value of the element position determined in step 4-1.

[0043] Step 4-3, geographic attribute retrieval: Perform geographic attribute retrieval based on the element value read in step 4-2, specifically:

[0044] A. When the element value is negative, the geographic attribute information is -1×element value.

[0045] B. When the element value is non-negative, jump to the Mth array of the local map grid two-dimensional array, where M = 100 × element value; in the Mth array of the local map grid two-dimensional array, subtract the lower limit of the longitude and latitude of the global map grid from the longitude and latitude of the target, multiply the results by 10000, round to zero, and only retain the last 2 integers as the element subscript of the b×b array, and read the corresponding element value, which is the geographic attribute information of the target location.

[0046] In step 4-1, when querying the location, subtract the lower limit of the longitude and latitude of the global map grid from the longitude and latitude of the target to be queried, and then multiply the results by 100 and round them towards zero to obtain the number of rows and columns of elements in the two-dimensional array of the global index grid.

[0047] The present invention has the following beneficial effects:

[0048] 1. Efficient computing performance and real-time response: This invention greatly optimizes the use of computing resources and can complete concurrent queries of up to 10,000 targets in less than one second on a standard VTS server, perfectly adapting to the stringent real-time requirements of existing VTS systems. In addition, this solution is easy to upgrade to a multi-threaded or distributed cluster architecture, further enhancing the system's ability to handle real-time queries on massive targets, fully meeting the needs of future business expansion.

[0049] 2. Memory usage optimization: While ensuring efficient query, the present invention also controls the usage of memory resources at an extremely low level. For a vast water area of ​​10,000 square kilometers, its innovative index grid and local map grid design, memory usage does not exceed 100MB, query time is less than 1 second, significantly reducing the memory burden of system operation and improving the flexibility and efficiency of system deployment.

[0050] 3. Strong compatibility and significant cost-effectiveness: The present invention has minimal impact on the existing VTS technical architecture, embodies extremely high compatibility, and can be easily integrated without large-scale transformation. This design concept takes into account the construction and maintenance costs of the VTS system, maximizes cost-effectiveness, provides users with a low-cost and highly available solution, and greatly improves the feasibility and attractiveness of market promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The flowchart of a method for gridding representation of geographical elements applicable to a vessel traffic management system of the present invention is shown.

[0052] Figure 2 A schematic diagram of a global map grid in the present invention is shown.

[0053] Figure 3 A schematic diagram of a geographic element map grid set in the present invention is shown.

[0054] Figure 4 A schematic diagram showing the principle of hierarchical compression and storage in the present invention is shown.

[0055] Figure 5 A schematic diagram showing the principle of geographic attribute retrieval in the present invention. DETAILED DESCRIPTION

[0056] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific preferred embodiments.

[0057] In the description of the present invention, it should be understood that the terms "left side", "right side", "upper part", "lower part" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. "First", "second" and the like do not indicate the importance of the components, and therefore cannot be understood as limiting the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution, and do not limit the scope of protection of the present invention.

[0058] like Figure 1 As shown, a method for gridding representation of geographic elements suitable for a vessel traffic management system includes the following steps.

[0059] Step 1: Build a global map grid

[0060] Determine the geographic space scope covered by the vessel traffic management system, calculate the longitude and latitude boundaries, and construct a global basic space map; then divide the global basic space map evenly into several small grids to form a Figure 2 The global map grid shown; each small grid has a side length of one ten-thousandth of a degree in both longitude and latitude.

[0061] The above-mentioned method for constructing the global map grid preferably includes the following steps.

[0062] Step 1-1, determine the geographic space scope covered by the vessel traffic management system, and calculate its longitude and latitude boundaries; the longitude and latitude boundaries include the upper longitude boundary, the lower longitude boundary, the upper latitude boundary and the lower latitude boundary.

[0063] Step 1-2, construct the global basic space boundary: the coordinates of the upper boundary of longitude and latitude are both integerized, and the coordinates of the lower boundary of longitude and latitude are both integerized, so as to form an adjusted global basic space map.

[0064] Step 1-3, divide into small grids: divide the global basic spatial map evenly into several small grids to form a global map grid; the side length of each small grid in the longitude and latitude directions is one ten-thousandth of a degree.

[0065] Step 2: Calculate the grid geographic attributes, including the following steps.

[0066] Step 2-1, set geographic elements: the user sets the type of geographic elements to be concerned about in the VTS system.

[0067] Step 2-2, extracting regional information: first, according to the geographic spatial scope and longitude and latitude boundaries determined in step 1, retrieve the electronic chart data source (also called geographic layer) with equal longitude and latitude boundaries; then extract the regional information of each geographic element type from the electronic chart data source.

[0068] Step 2-3, calculate geographic attributes: For each area extracted in step 2-2, use the fast projection algorithm to determine its mapping in the global map grid, so as to calculate the geographic element type of each small grid, and then form the following Figure 3 The geographic element map grid set shown. In the present invention, the geographic element types are all assigned digital values, as described later.

[0069] That is, the present invention calls relevant geographic layers in a targeted manner according to the business function requirements of the VTS system. By reading and subdividing the boundaries of each area, the fast projection algorithm is used to determine the mapping of each area in the global grid, and the geographical features of each grid are calculated in detail. These attribute data are organized and stored in a specially designed global map grid two-dimensional array, laying the foundation for subsequent fast access.

[0070] Furthermore, the above method of mapping each area in the global map grid using a fast projection algorithm preferably includes the following steps.

[0071] Step 2-3A, constructing a boundary point set: For each area extracted in step 2-2, the area boundary is refined. The specific refinement method is: points are evenly taken on the boundary line of each area at an interval of less than a meters to form a boundary point set; wherein a is less than the minimum recognition accuracy of the ship radar. In this embodiment, it is preferably 10 meters.

[0072] Step 2-3B, generate a boundary map grid list: for each boundary point of each area, determine the small grid number to which it belongs on the global basic space map, thereby generating a boundary map grid list for the corresponding area.

[0073] Step 2-3C, constructing a regional coverage map grid set: by means of horizontal scanning and vertical scanning methods, respectively calculating the map grids covered by each regional boundary line, forming two independent horizontal regional coverage map grid sets and vertical regional coverage map grid sets.

[0074] Step 2-3D, build a precise coverage map grid set: compare the horizontal area coverage map grid set and the vertical area coverage map grid set, and directly include the small grids with consistent comparison results into the precise coverage map grid set; for each small grid with inconsistent comparison results, perform spatial relationship operations and include the small grids located in the corresponding area into the precise coverage map grid set.

[0075] Step 2-3E, repeat step 2-3A to step 2-3D to complete the precise coverage map grid sets of all regions in turn; then merge and summarize the precise coverage map grid sets of all regions to finally obtain a complete geographic element map grid set.

[0076] Step 3: Hierarchical compression and storage, such as Figure 4 As shown, the following steps are included.

[0077] Step 3-1, divide the index grid: divide the geographic element map grid set formed in step 2 evenly into a number of square index grids; each index grid includes b×b ​​small grids; where b>10, in this embodiment, it is preferred that each index grid includes 100×100 small grids.

[0078] Step 3-2: Hierarchical compression and storage: Traverse the small grids in each index grid in turn, and perform hierarchical compression and storage according to the following method:

[0079] A. When the geographic attributes of all small grids in the index grid are the same, the b×b small grids are merged and compressed into a single index grid.

[0080] B. When a small grid in an index grid has two or more geographic attributes, the current index grid is a multi-attribute index grid and cannot be compressed.

[0081] Step 3-3, construct a two-dimensional array of global index grids: Based on the traversal results of step 3-2, and by classifying and assigning values ​​to single index grids and multi-attribute index grids, a two-dimensional array of global index grids containing all index grids is constructed.

[0082] The method for constructing the above-mentioned index grid two-dimensional array preferably includes the following steps.

[0083] Step 3-3A, geographic feature type assignment: assign a positive integer to each geographic feature type in step 2-1.

[0084] Step 3-3B, single index grid assignment: query the geographic feature type assignment of each single index grid, and then multiply the queried geographic feature type assignment by -1 to obtain the element assignment of each single index grid.

[0085] Step 3-3C, multi-attribute index grid assignment: Assume that the initial code value of each multi-attribute index grid is 0, and assign non-negative values ​​to the elements of all multi-attribute index grids traversed in step 3-2 in ascending order.

[0086] Step 3-3D, construct a two-dimensional array of index grids: According to the order of the index grids divided in step 3-1, for each index grid, the corresponding index grid is assigned according to the method of step 3-3B or step 3-3C, thereby obtaining a two-dimensional array of global index grids after the assignment.

[0087] Step 3-4, construct a two-dimensional array of local map grids: According to the position and number of the multi-attribute index grids in step 3-3 and the set of geographic feature map grids in step 2, construct a two-dimensional array of local map grids; wherein the two-dimensional array of local map grids includes the geographic attributes of each small grid in all multi-attribute index grids.

[0088] The method for constructing the above-mentioned local map grid two-dimensional array preferably includes the following steps.

[0089] Step 3-4A, construct a two-dimensional array of blank local map grids: Assume that the total number of multi-attribute index grids in step 3-3 is N, then construct a two-dimensional array of blank local map grids with b rows and b×N columns.

[0090] Step 3-4B, geographic attribute assignment: traverse the geographic attribute values ​​of the small grids in each multi-attribute index grid in the geographic element map grid set, and copy them to the corresponding positions of the blank local map grid two-dimensional array, thereby forming a local map grid two-dimensional array with geographic attribute values.

[0091] Step 4: Quick retrieval of geographic attributes: Figure 5 As shown, based on the location of the target to be queried, the relevant global index grid two-dimensional array and the local map grid two-dimensional array are located to timely extract the geographic attribute information of the target location.

[0092] The above-mentioned method for rapid retrieval of geographical attributes preferably includes the following steps.

[0093] Step 4-1, position query: According to the longitude and latitude position information of the target to be queried, determine the element position in the global index grid two-dimensional array. When querying the position, the longitude and latitude of the target to be queried are respectively subtracted from the lower limit of the longitude and latitude of the global map grid, and then the result is multiplied by 100, and zero-rounded, so as to obtain the number of rows and columns of the elements in the global index grid two-dimensional array.

[0094] Step 4-2, read element value: read the element value of the element position determined in step 4-1.

[0095] Step 4-3, geographic attribute retrieval: Perform geographic attribute retrieval based on the element value read in step 4-2, specifically:

[0096] A. When the element value is negative, the geographic attribute information is -1×element value.

[0097] B. When the element value is non-negative, jump to the Mth array of the local map grid two-dimensional array, where M = 100 × element value; in the Mth array of the local map grid two-dimensional array, subtract the lower limit of the longitude and latitude of the global map grid from the longitude and latitude of the target, multiply the results by 10000, round to zero, and only retain the last two integers (the ones and tens) as the element subscript of the b×b array, and read the corresponding element value, which is the geographic attribute information of the target location.

[0098] The preferred embodiments of the present invention are described in detail above; however, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.

Claims

1. A method for representing geographic elements in a grid system suitable for a vessel traffic management system, characterized in that: The steps include: Step 1: Construct a global map grid: determine the geographic space covered by the vessel traffic management system, calculate the longitude and latitude boundaries, and construct a global basic spatial map; then divide the global basic spatial map evenly into a number of small grids to form a global map grid; the side length of each small grid in the longitude and latitude directions is one ten-thousandth of a degree; Step 2: Calculate the grid geographic attributes, including the following steps: Step 2-1, set geographic elements: the user sets the type of geographic elements to be concerned in the VTS system; Step 2-2, extracting regional information: first, according to the geographic spatial scope and longitude and latitude boundaries determined in step 1, retrieve the electronic nautical chart data source with equal longitude and latitude boundaries; then extract the regional information of each geographic element type from the electronic nautical chart data source; Step 2-3, calculate geographic attributes: for each area extracted in step 2-2, use the fast projection algorithm to determine its mapping in the global map grid, so as to calculate the geographic element type of each small grid, and then form a geographic element map grid set; Step 3: Hierarchical compression and storage, including the following steps: Step 3-1, dividing the index grid: the geographic element map grid set formed in step 2 is evenly divided into a number of square index grids; each index grid includes b×b ​​small grids; where b>10; Step 3-2: Hierarchical compression and storage: Traverse the small grids in each index grid in turn, and perform hierarchical compression and storage according to the following method: A. When the geographic attributes of all small grids in the index grid are the same, the b×b small grids are merged and compressed into a single index grid; B. When a small grid in an index grid has two or more geographic attributes, the current index grid is a multi-attribute index grid and cannot be compressed; Step 3-3, constructing a two-dimensional array of global index grids: Based on the traversal results of step 3-2, and by classifying and assigning values ​​to single index grids and multi-attribute index grids, a two-dimensional array of global index grids containing all index grids is constructed; Step 3-4, constructing a two-dimensional array of local map grids: constructing a two-dimensional array of local map grids according to the position and number of the multi-attribute index grids in step 3-3 and the set of geographic element map grids in step 2; wherein the two-dimensional array of local map grids includes the geographic attributes of each small grid in all multi-attribute index grids; Step 4: Rapid retrieval of geographic attributes: Based on the location of the target to be queried, locate the relevant global index grid two-dimensional array and the local map grid two-dimensional array, and extract the geographic attribute information of the target location in a timely manner.

2. The method for representing geographic elements in a grid based manner suitable for a vessel traffic management system according to claim 1, characterized in that: In step 1, the method for constructing the global map grid includes the following steps: Step 1-1, determine the geographic space scope covered by the vessel traffic management system, and calculate its longitude and latitude boundaries; the longitude and latitude boundaries include the upper longitude boundary, the lower longitude boundary, the upper latitude boundary and the lower latitude boundary; Step 1-2, construct the global basic space boundary: the coordinates of the upper boundary of longitude and the upper boundary of latitude are both integerized, and the coordinates of the lower boundary of longitude and the lower boundary of latitude are both integerized, so as to form an adjusted global basic space map; Step 1-3, divide into small grids: divide the global basic spatial map evenly into several small grids to form a global map grid; the side length of each small grid in the longitude and latitude directions is one ten-thousandth of a degree.

3. The method for representing geographic elements in a grid based manner suitable for a vessel traffic management system according to claim 1, characterized in that: In step 2-3, the method of mapping each area in the global map grid using a fast projection algorithm includes the following steps: Step 2-3A, constructing a boundary point set: for each area extracted in step 2-2, the regional boundary is refined, and the specific refinement method is: points are uniformly taken on the boundary line of each area at an interval of less than a meters, thereby forming a boundary point set; wherein a is less than the minimum recognition accuracy of the ship radar; Step 2-3B, generate a boundary map grid list: for each boundary point of each area, determine the small grid number to which it belongs on the global basic space map, so as to generate a boundary map grid list of the corresponding area; Step 2-3C, constructing a regional coverage map grid set: by means of horizontal scanning and vertical scanning methods, respectively calculating the map grids covered by each regional boundary line, forming two independent horizontal regional coverage map grid sets and vertical regional coverage map grid sets; Step 2-3D, constructing a precise coverage map grid set: compare the horizontal area coverage map grid set and the vertical area coverage map grid set, and directly include the small grids with consistent comparison results into the precise coverage map grid set; perform spatial relationship operations on each small grid with inconsistent comparison results, and include the small grids in the corresponding area into the precise coverage map grid set; Step 2-3E, repeat step 2-3A to step 2-3D to complete the precise coverage map grid sets of all regions in turn; then merge and summarize the precise coverage map grid sets of all regions to finally obtain a complete geographic element map grid set.

4. The method for representing geographic elements in a grid based manner suitable for a vessel traffic management system according to claim 3, characterized in that: In step 2-3A, a=10 meters.

5. The method for representing geographic elements in a grid based manner suitable for a vessel traffic management system according to claim 1, characterized in that: Step 3-1, b=100.

6. The method for representing geographic elements in a grid based manner suitable for a vessel traffic management system according to claim 1, characterized in that: In step 3-3, the method for constructing the index grid two-dimensional array includes the following steps: Step 3-3A, geographic feature type assignment: assign positive integers to each geographic feature type in step 2-1; Step 3-3B, single index grid assignment: query the geographic feature type assignment of each single index grid, and then multiply the queryed geographic feature type assignment by -1 to obtain the element assignment of each single index grid; Step 3-3C, multi-attribute index grid assignment: Assume that the initial code value of each multi-attribute index grid is 0, and assign non-negative values ​​to the elements of all multi-attribute index grids traversed in step 3-2 in ascending order; Step 3-3D, construct a two-dimensional array of index grids: According to the order of the index grids divided in step 3-1, for each index grid, the corresponding index grid is assigned according to the method of step 3-3B or step 3-3C, thereby obtaining a two-dimensional array of global index grids after the assignment.

7. The method for representing geographic elements in a grid based manner suitable for a vessel traffic management system according to claim 1, characterized in that: Step 3-4, a method for constructing a two-dimensional array of local map grids, comprising the following steps: Step 3-4A, construct a two-dimensional array of blank local map grids: Assume that the total number of multi-attribute index grids in step 3-3 is N, then construct a two-dimensional array of blank local map grids with b rows and b×N columns; Step 3-4B, geographic attribute assignment: traverse the geographic attribute values ​​of the small grids in each multi-attribute index grid in the geographic element map grid set, and copy them to the corresponding positions of the blank local map grid two-dimensional array, thereby forming a local map grid two-dimensional array with geographic attribute values.

8. The method for representing geographic elements in a grid based manner suitable for a vessel traffic management system according to claim 1, characterized in that: In step 4, the method for quickly retrieving geographic attributes includes the following steps: Step 4-1, position query: according to the latitude and longitude position information of the target to be queried, determine the element position in the two-dimensional array of the global index grid; Step 4-2, read element value: read the element value of the element position determined in step 4-1; Step 4-3, geographic attribute retrieval: Perform geographic attribute retrieval based on the element value read in step 4-2, specifically: A. When the element value is negative, the geographic attribute information is -1×element value; B. When the element value is non-negative, jump to the Mth array of the local map grid two-dimensional array, where M = 100 × element value; in the Mth array of the local map grid two-dimensional array, subtract the lower limit of the longitude and latitude of the global map grid from the longitude and latitude of the target, multiply the results by 10000, round to zero, and only retain the last 2 integers as the element subscript of the b×b array, and read the corresponding element value, which is the geographic attribute information of the target location.

9. The method for representing geographic elements in a grid format suitable for a vessel traffic management system according to claim 8, characterized in that: In step 4-1, when querying the location, subtract the lower limit of the longitude and latitude of the global map grid from the longitude and latitude of the target to be queried, and then multiply the results by 100 and round them towards zero to obtain the number of rows and columns of elements in the two-dimensional array of the global index grid.

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