A grid representation method of geographical elements suitable for vessel traffic management systems

Abstract

This invention discloses a gridded representation method for geographic elements suitable for a vessel traffic management system. By combining the characteristics of a vessel traffic management system with refined gridding of water areas, the method converts geographic elements into information based on geographic grids through high-performance computing. A dual-layer grid compression storage strategy is employed to enable the system to achieve real-time, high-speed access and processing of geographic information with low resource consumption. This dual-layer grid compression storage strategy enables real-time, high-performance querying of geographic elements by a VTS system with low resource consumption, resulting in low resource consumption, high real-time performance, and strong flexibility.

Description

Technical Field

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

[0002] The Vessel Traffic Management System (VTS) is primarily responsible for monitoring the dynamics of vessels within 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, placing extremely high demands on the system's real-time performance and accuracy. As the core system for water safety supervision, VTS integrates a variety of data to accurately display water traffic trends. However, faced with 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, limiting the dynamic application efficiency of geographic feature data.

[0003] The S57 chart design focuses on data storage and exchange rather than fast query and display, prompting chart vendors to develop customized SENC (chart system vendor proprietary format) to optimize display performance. These customized solutions vary from manufacturer to manufacturer. Although they improve display efficiency, they require processing a large number of irregular points, lines, and surface elements in the chart when querying the geographic elements of the target's location in real time. In particular, with more than 100 layers of different geographic elements spread across a VTS monitoring area, which generally exceeds 50 square kilometers, traditional spatial algorithms are extremely computationally intensive and cannot meet real-time computing requirements. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the shortcomings of the above-mentioned existing technologies and provide a gridded representation method for geographic elements suitable for a vessel traffic management system. This gridded representation method for geographic elements suitable for a vessel traffic management system implements gridded subdivision of geographic space and utilizes pre-calculation technology to store spatial attribute information within a grid framework. Combined with an efficient index grid and local map grid compression storage strategy, this method enables rapid positioning and access when querying geographic attribute information of a vessel's target location, significantly reducing the burden of complex geometric calculations and thus overcoming the application barriers of geographic elements in real-time computing in VTS systems. The present invention has the advantages 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 representing geographic elements in a grid format suitable for 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 focused on in the VTS system.

[0010] Step 2-2, extracting regional information: first, based on the geographic spatial scope and longitude and latitude boundaries determined in step 1, retrieve the electronic nautical chart data source with the same longitude and latitude boundaries; then extract the regional information of each geographic feature 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, thereby calculating the geographic feature type of each small grid, and then forming a geographic feature 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 as follows:

[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, construct a two-dimensional array of global index grids containing all index grids.

[0018] Step 3-4, construct a two-dimensional array of local map grids: Based on the position and number of the multi-attribute index grids in step 3-3 and the geographic feature map grid set 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 spatial boundary: convert the coordinates of the upper longitude boundary and the upper latitude boundary into integers, and convert the coordinates of the lower longitude boundary and the lower latitude boundary into integers, thereby forming an adjusted global basic spatial map.

[0023] Steps 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 steps 2-3, the method of mapping each region onto 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 intervals 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 spatial map, and thus generate a boundary map grid list for the corresponding area.

[0027] Step 2-3C, constructing a regional coverage map grid set: by using horizontal scanning and vertical scanning methods, respectively calculate the map grids covered by each regional boundary line to form 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 with 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 steps 2-3A to 2-3D to complete the precise coverage map grid sets of all regions in sequence; then merge and summarize the precise coverage map grid sets of all regions to finally obtain a complete geographic feature 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 value to each geographic feature type in step 2-1.

[0034] Step 3-3B, single index grid assignment: query the geographic element type assignment of each single index grid, and then multiply the queryed geographic element 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, constructing a two-dimensional array of index grids: Based on the order of the index grids divided in step 3-1, for each index grid, assign the corresponding index grid value according to the method of step 3-3B or step 3-3C, and then obtain the assigned global two-dimensional array of index grids.

[0037] Step 3-4: The method for constructing a two-dimensional array of a local map grid includes 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 feature 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 off to the nearest integer, and retain only the last two digits as the element subscript of the b×b array. 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. High-Efficiency Computing Performance and Real-Time Response: This solution significantly optimizes computing resource utilization, enabling concurrent queries of up to 10,000 targets in less than one second on a standard VTS server, perfectly meeting the stringent real-time requirements of existing VTS systems. Furthermore, this solution is easily upgradeable to a multi-threaded or distributed cluster architecture, further enhancing the system's ability to handle massive real-time queries, fully meeting the needs of future business expansion.

[0049] 2. Memory Optimization: While ensuring efficient queries, this invention also minimizes memory usage. For a vast water area of ​​10,000 square kilometers, its innovative index grid and local map grid design achieves a memory footprint of less than 100MB and query times of less than one second, significantly reducing the system's memory burden and improving the flexibility and efficiency of system deployment.

[0050] 3. Strong Compatibility and Significant Cost-Effectiveness: This invention minimally impacts existing VTS technology architecture, demonstrating high compatibility and enabling easy integration without requiring major modifications. This design approach balances VTS system construction and maintenance costs, maximizing cost-effectiveness and providing users with a low-cost, highly available solution, significantly enhancing the feasibility and attractiveness of market deployment. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The flowchart of the present invention shows a method for representing geographic elements in a grid suitable for a vessel traffic management system.

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

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

[0054] Figure 4 A schematic diagram showing the principles 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 is shown. DETAILED DESCRIPTION

[0056] The present invention will be further described in detail below with reference to 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," "lower," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Terms such as "first" and "second" do not indicate the importance of components and therefore should not be construed as limitations on the present invention. The specific dimensions used in this embodiment are intended only to illustrate 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 geographical elements applicable to 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 latitude and longitude boundaries, and construct a global basic space map; then divide the global basic space map evenly into several small grids, thus forming a Figure 2 The global map grid is 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 spatial boundary: convert the coordinates of the upper longitude boundary and the upper latitude boundary into integers, and convert the coordinates of the lower longitude boundary and the lower latitude boundary into integers, thereby forming an adjusted global basic spatial map.

[0064] Steps 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 focused on in the VTS system.

[0067] Step 2-2, extracting regional information: First, based on the geographic spatial scope and longitude and latitude boundaries determined in step 1, retrieve the electronic nautical chart data source (also known as the geographic layer) with the same longitude and latitude boundaries; then extract the regional information of each geographic feature type from the electronic nautical 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, thereby calculating the geographic feature type of each small grid, and then forming the following Figure 3 The geographic element map grid set shown in FIG. In the present invention, the geographic element types are all assigned digital values, as described later.

[0069] In other words, this invention specifically calls upon relevant geographic layers based on the business functional requirements of the VTS system. By reading and segmenting each region's boundaries, a fast projection algorithm is used to determine the mapping of each region within the global grid. The geographic characteristics of each grid are then calculated in detail. This attribute data is then organized and stored in a specially designed two-dimensional global map grid array, paving the way for subsequent rapid access.

[0070] Furthermore, the above method of mapping each area into 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 selected on the boundary line of each area at intervals less than a meters to form a boundary point set; where 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 spatial map, and thus generate a boundary map grid list for the corresponding area.

[0073] Step 2-3C, constructing a regional coverage map grid set: by using horizontal scanning and vertical scanning methods, respectively calculate the map grids covered by each regional boundary line to form 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 with 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 steps 2-3A to 2-3D to complete the precise coverage map grid sets of all regions in sequence; then merge and summarize the precise coverage map grid sets of all regions to finally obtain a complete geographic feature 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, 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. 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 as follows:

[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, construct a two-dimensional array of global index grids containing all index grids.

[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 value to each geographic feature type in step 2-1.

[0084] Step 3-3B, single index grid assignment: query the geographic element type assignment of each single index grid, and then multiply the queryed geographic element 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, constructing a two-dimensional array of index grids: Based on the order of the index grids divided in step 3-1, for each index grid, assign the corresponding index grid value according to the method of step 3-3B or step 3-3C, and then obtain the assigned global two-dimensional array of index grids.

[0087] Step 3-4, construct a two-dimensional array of local map grids: Based on the position and number of the multi-attribute index grids in step 3-3 and the geographic feature map grid set 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 two-dimensional array of local map grids 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 feature 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 extract the geographic attribute information of the target location in a timely manner.

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

[0093] Step 4-1. Location Query: Based on the longitude and latitude of the target to be queried, determine the position of its element in the two-dimensional array of the global index grid. To perform the location query, 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, multiply the result by 100, and round down to the nearest integer. This will determine the number of rows and columns of the element in the two-dimensional array of the global index grid.

[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 off to the nearest integer, and retain only the last two integers (the ones digit and the tens digit) as the element subscript of the b×b array. 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 fall within the scope of protection of the present invention.

Claims

1. A method for representing geographical elements in a grid format suitable for a vessel traffic management system, characterized by: 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 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. Step 2: Calculate the grid geographic attributes, including the following steps: Step 2-1, set geographic elements: users set the type of geographic elements they want to focus on in the VTS system; Step 2-2, extracting regional information: First, based on the geographic spatial scope and longitude and latitude boundaries determined in step 1, retrieve the electronic nautical chart data source with the same longitude and latitude boundaries; then extract the regional information of each geographic feature 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, thereby calculating the geographic feature type of each small grid, and then forming a geographic feature 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 as follows: 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: Based on the position and number of the multi-attribute index grids in step 3-3 and the geographic feature map grid set 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; 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 system 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 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 spatial boundary: convert the coordinates of the upper longitude boundary and the upper latitude boundary into integers, and convert the coordinates of the lower longitude boundary and the lower latitude boundary into integers, thereby forming an adjusted global basic spatial map; Steps 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 format suitable for a vessel traffic management system according to claim 1, characterized in that: In step 2-3, the method for mapping each region onto the global map grid using a fast projection algorithm includes the following steps: Step 2-3A, constructing a boundary point set: For each region extracted in step 2-2, the region boundary is refined. The specific refinement method is: points are uniformly selected on the boundary line of each region at intervals less than a meters to form a boundary point set; where a is less than the minimum recognition accuracy of the ship radar; Step 2-3B, Generate Boundary Map Grid List: For each boundary point in each area, determine the small grid number to which it belongs on the global basic spatial map, and thus generate the boundary map grid list for the corresponding area; Step 2-3C, constructing a regional coverage map grid set: by using 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, build a precise coverage map grid set: compare the horizontal area coverage map grid set with the vertical area coverage map grid set, and directly incorporate 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 incorporate the small grids in the corresponding area into the precise coverage map grid set; Step 2-3E: Repeat steps 2-3A to 2-3D to complete the precise coverage map grid sets of all regions in sequence; then merge and summarize the precise coverage map grid sets of all regions to finally obtain a complete geographic feature map grid set.

4. The method for representing geographic elements in a grid format 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 format 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 format 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 Element Type Assignment: Assign a positive integer value to each geographic element type in Step 2-1. Step 3-3B, Single Index Grid Assignment: Query the geographic element type assignment for each single index grid, and then multiply the queryed geographic element type assignment by -1 to obtain the element assignment for 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, constructing a two-dimensional array of index grids: Based on the order of the index grids divided in step 3-1, for each index grid, assign the corresponding index grid value according to the method of step 3-3B or step 3-3C, and then obtain the assigned global two-dimensional array of index grids.

7. The method for representing geographic elements in a grid format suitable for a vessel traffic management system according to claim 1, characterized in that: Step 3-4: The method for constructing a two-dimensional array of a local map grid includes 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 feature 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 format 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: Based on the latitude and longitude position information of the target to be queried, determine the element position of the target 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 off to the nearest integer, and retain only the last two digits as the element subscript of the b×b array. 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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