Ocean current three-dimensional visual presentation method based on moving line

Abstract

The invention belongs to the field of ocean current visualization, and particularly relates to an ocean current three-dimensional visualization presentation method based on a moving line. Comprising the following steps: 1) acquiring ocean current field data, and screening acquisition points; (2) complementing the screened data; and 3) performing visual presentation based on the complemented ocean current data. According to the method, the dynamic line mode is adopted for presentation, the motion characteristics of ocean current field data among different depth levels in the ocean three-dimensional environment can be better highlighted, and meanwhile, the visual presentation of the ocean current field more pays attention to the vortex characteristics formed by ocean currents.

Description

Technical Field

[0001] The invention belongs to the field of ocean current visualization, and specifically is a three-dimensional visualization presentation method of ocean current based on moving lines. Background Art

[0002] "A visualization method for ocean three-dimensional temperature-salinity flow data (patent publication number CN118708644A)" mainly pre-processes the original data, generates contour images, and presents them through color filling and visualization, as well as "Global ocean current display method and system based on naked-eye 3D" (patent publication number CN202410751191.9), which optimizes the final presentation results of data visualization. The above methods are all methods for rendering images generated by ocean current field data, which is actually a layered presentation of data. Users can only obtain ocean current conditions at a single or multiple depth levels on the three-dimensional visualization interface, and it is difficult to obtain the movement of the ocean current field in a three-dimensional environment on the three-dimensional visualization map. Summary of the invention

[0003] The purpose of the present invention is to provide a three-dimensional visualization presentation method of ocean currents based on dynamic lines. The presentation in the form of dynamic lines can better highlight the movement characteristics of ocean current field data between different depth levels in a three-dimensional ocean environment. At the same time, the visualization presentation of the ocean current field pays more attention to the vortex characteristics formed by the ocean currents.

[0004] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0005] A method for three-dimensional visualization of ocean currents based on moving lines comprises the following steps:

[0006] 1) Obtain ocean current data and screen the collection points;

[0007] 2) Complete the filtered data;

[0008] 3) Visualization based on the completed ocean current data.

[0009] The step 1) comprises the following steps:

[0010] 1.1) Divide the entire ocean current field data into M three-dimensional sub-areas of equal size according to latitude, longitude and depth information;

[0011] 1.2) Starting from a certain cross section in a certain three-dimensional sub-region ocean current field, according to the number of data points N on the cross section, N threads are started in a multi-threaded manner to simultaneously generate a set of N data points;

[0012] 1.3) Each thread selects the first time point in the time series on the section as the initial point, assuming it is point A1;

[0013] 1.4) Find the next acquisition point in the direction of the A1 space vector, and calculate the point with the smallest angle change among all the acquisition points with existing data adjacent to point A1 as the next point of the ocean current field motion trajectory, assuming it is point A2;

[0014] 1.5) Repeat step 1.4) until all the acquisition point information of the time series is completely covered, and the acquisition point array (A1, A2, A3....A n ).

[0015] The step 2) comprises the following steps:

[0016] 2.1) The arc formed by the direction vectors of points A1 and A2 is regarded as part of the sphere, and the direction vector of point A1 is the tangent line of the sphere at point A1;

[0017] 2.2) Divide the arc into several equal parts according to the angle between it and the center of the sphere, and obtain the longitude and latitude coordinates and depth information of each point;

[0018] 2.3) Re-inject the newly obtained data into the array, overwriting the original array information;

[0019] 2.4) Repeat steps 2.2) and 2.3) until (A1, A2, A3....A) is completed. n ) to complete all the data.

[0020] In the actual application scenarios of ocean current field visualization, there are two situations: real-time monitoring and historical data presentation. If it is a historical data presentation scenario, the completed data is directly saved to the database for persistent storage, covering the original data information. If it is a real-time monitoring scenario, the data is saved to the database after the next round of data information is received and the collection point data screening and data completion are completed.

[0021] The step 3) comprises the following steps:

[0022] 3.1) Count the 3D subspace areas within the current access field of view and calculate the total number of cross-section initial points. If the boundary of a front-end access request is within a certain 3D subspace area, it is counted as a complete 3D subspace area.

[0023] 3.2) Generate a corresponding number of threads in the program code of the backend server according to the total number of initial points of the cross section;

[0024] 3.3) According to each thread, set the data reading interval of a certain thread according to the time interval between two collection points;

[0025] 3.4) Read data according to the time interval, push the data reading results to the front-end program, and generate the moving line through the front-end code;

[0026] 3.5) Determine whether the last data in the array has been read. If so, return to the first data in the array to re-read and push it to the front-end program; otherwise, end the rendering process.

[0027] The step 3.3) is specifically as follows:

[0028] Assume that the acquisition point times of point A1 and point A2 are time1 and time2 respectively, then the data reading interval is the length of the interval between time1 and time2, divided by the total number of supplementary data points + 1.

[0029] A three-dimensional visualization presentation system of ocean currents based on dynamic lines, comprising:

[0030] Data collection point screening module, used to obtain ocean current field data and screen the collection points;

[0031] Data completion module, used to complete the filtered data;

[0032] The data visualization module is used for visualization based on the completed ocean current data.

[0033] A three-dimensional visualization presentation device for ocean currents based on moving lines comprises a memory and a processor; the memory is used to store a computer program; the processor is used to implement the three-dimensional visualization presentation method for ocean currents based on moving lines when executing the computer program.

[0034] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, a three-dimensional visualization method for ocean currents based on moving lines is implemented.

[0035] The present invention has the following beneficial effects and advantages:

[0036] 1. Compared with other inventions that use pictures (layers) to visualize ocean current fields, the method provided by the present invention can present the movement trajectories of ocean currents between different layers, which is closer to the actual movement of ocean currents.

[0037] 2. The present invention generates the overall motion trajectory of the ocean current field by dividing the overall data into three-dimensional space and generating trajectory lines through multi-threading. Multiple threads and arrays are independent of each other, and the CPU and memory computing resources of the back-end server and the front-end access client can be fully utilized, and optimization can be performed according to the overall data scale and visualization effect requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Overall flow chart of the present invention

[0039] Figure 2 Flowchart of the collection point data screening method;

[0040] Figure 3 Flowchart of data completion method;

[0041] Figure 4 Flowchart of visual presentation method;

[0042] Figure 5 Schematic diagram of the presentation results of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0044] like Figure 5 As shown in the figure, in GIS (Geographic Information System) visualization, a moving line refers to a line used to represent the path of movement of a person, object or phenomenon in geographic space. It intuitively shows the trajectory of movement and can help users better understand the dynamic process in geographic space.

[0045] The ocean current field data in the marine environment mainly exists in the .nc file format. Through data preprocessing, the data information under the grid is formed. The content of the data information includes the collection time time, the longitude lon of the collection point, the latitude lat of the collection point, the depth deep of the collection point, and three direction vectors u, v and w, which are used to indicate the movement direction of the ocean current at this point.

[0046] After preprocessing, the overall raw data of the ocean current field collected in a certain time period is stored in the database in the form of a time series, that is, it contains the data collection results of all monitoring points at each time point. It can be regarded as the collected data at a certain time point time1 forming a three-dimensional grid. Assume that this grid is a grid containing 3*3*3 and a total of 27 collection points. Similarly, Time2 will also have corresponding 27 collection points. When visualizing the movement trajectory of the ocean current field in the form of dynamic lines, it can be regarded as a line connecting a certain point in time1 (assuming it is A1) to a certain point at time2. By analogy, a line connecting a certain point at time3 will also be generated. By connecting these points in a certain way, it is possible to form an ocean current movement trajectory close to the actual situation.

[0047] At the same time, it can be seen that the series of moving lines generated by the ocean current trajectories starting from different points are unrelated to each other and are generated independently. This means that when the data scale is large and the visual presentation details are high, technologies such as multi-threaded processing on the back end and batch presentation on the front end can be used. At the same time, in interactive operations, the number of moving lines presented can be automatically adjusted according to the focal length to make full use of computer resources and optimize system performance.

[0048] like Figure 1 As shown, the method of the present invention comprises the following 3 parts:

[0049] (1) Collection point data screening method

[0050] The process flow is as follows Figure 2 As shown:

[0051] A. Divide the entire ocean current field data into M equal-sized 3D sub-areas according to latitude, longitude and depth information. The number of 3D sub-areas can be set in advance based on the total number of collection points and server performance.

[0052] B. Starting from a certain cross section (here, the cross section formed by the points with the same and smallest latitude) in the ocean current field of the three-dimensional sub-region (assuming it is M1), if there are N points on the cross section, start N threads in a multi-threaded manner, and generate a set of N data points at the same time, and store the data information in an array manner, that is, all data needs to be generated and processed by M*N threads to form an M*N array;

[0053] C. Each thread selects the first time point (i.e. time1) on the section in the time series as the initial point, assuming it is point A1;

[0054] D. First, find the next point at time 2 according to the direction of the A1 space vector. The point with the smallest angle change (i.e. the smallest included angle) among all the adjacent data collection points is used as the next point of the ocean current field motion trajectory, which is assumed to be point A2.

[0055] E. Continue to search for the next point through point A2 according to the above method, assuming it is point A3, and so on, until all the collection point information of the time series is completely covered. The collection point data generated by the above method is assumed to be (A1, A2, A3...A n ).

[0056] (2) Data completion method

[0057] For the array (A1, A2, A3....A n), if we directly call and present the lines formed by these data, the visualization effect of these long line segments will become very discontinuous, and the changes between the lines are not smooth. The visualization effect is very different from the actual situation and requirements. Therefore, it is necessary to add multiple line segments between these data points to ensure a smooth transition between the line segments. In terms of visualization, a running trajectory close to a curve is formed, which is closer to the actual effect of ocean current movement.

[0058] The process of data completion method is as follows Figure 3 As shown:

[0059] A. Take the arc formed by the direction vectors of points A1 and A2. This arc is regarded as a part of the sphere. The direction vector of point A1 is the tangent line of the sphere at point A1.

[0060] B. Divide this arc into several equal parts according to the angle with the center of the sphere, and obtain the latitude and longitude coordinates and depth information of each point. The specific number of parts is related to the final effect requirements of the visualization, that is, when the focal length of the system is larger and the level is higher, the amount of data required to complete is larger, but the larger the amount of newly added data, the larger the amount of data for each data and the overall scale of the data will become, and accordingly, the greater the memory resource requirements of the system will be, and the data call speed will be slower accordingly;

[0061] C. Re-inject the data generated by the completion method into the array, overwriting the previous array information;

[0062] D. Use the above method repeatedly until (A1, A2, A3...A n ) complete all data;

[0063] E. In the actual application scenarios of ocean current field visualization, there are two situations, real-time monitoring and historical data presentation. If it is a historical data presentation scenario, there is sufficient time to save the above data to the database for persistent storage, overwriting the previously preprocessed original data information. If it is a real-time monitoring scenario, the data will be saved to the database after the next round of data information is received and the above two steps of data screening and data completion are completed.

[0064] (3) Visualization presentation method

[0065] like Figure 4 As shown: Specifically includes the following contents:

[0066] 1. Count the 3D subspace areas within the field of view of this visit, and then calculate the total number of cross-section initial points. If the boundary of a front-end access request is within a certain 3D subspace area, it is counted as a complete 3D subspace area.

[0067] 2. Generate a corresponding number of threads in the program code of the backend server according to the total number of initial points of the cross section;

[0068] 3. Each thread sets the data reading interval of a certain thread according to the time interval between two collection points, that is, the collection point time of A1 is time1 and the collection point time of A2 is time2, then the data reading interval is the length of the interval between time1 and time2, divided by the total number of supplemented data points + 1. If in the function of presenting historical data tracks, the reading multiple can be reduced in sequence according to the selected time speed.

[0069] 4. Read data according to the time interval, push the data reading results to the front-end program, and generate the moving line through the front-end code;

[0070] 5. Determine whether the last data in the array has been read. If so, return to the first data in the array to re-read and push it to the front-end program.

Claims

1. A three-dimensional visualization method for ocean currents based on dynamic lines, characterized in that: The following steps are involved: 1) Obtain ocean current data and screen the collection points; 2) Complete the filtered data; 3) Visualization based on the completed ocean current data.

2. The method for three-dimensional visualization of ocean currents based on dynamic lines according to claim 1, characterized in that: The step 1) comprises the following steps: 1.1) Divide the entire ocean current field data into M three-dimensional sub-areas of equal size according to latitude, longitude and depth information; 1.2) Starting from a certain cross section in a certain three-dimensional sub-region ocean current field, according to the number of data points N on the cross section, N threads are started in a multi-threaded manner to simultaneously generate a set of N data points; 1.3) Each thread selects the first time point in the time series on the section as the initial point, assuming it is point A1; 1.4) Find the next acquisition point in the direction of the A1 space vector, and calculate the point with the smallest angle change among all the acquisition points with existing data adjacent to point A1 as the next point of the ocean current field motion trajectory, assuming it is point A2; 1.5) Repeat step 1.4) until all the acquisition point information of the time series is completely covered, and the acquisition point array (A1, A2, A3....A n ).

3. The method for three-dimensional visualization of ocean currents based on moving lines according to claim 1, characterized in that: The step 2) comprises the following steps: 2.1) The arc formed by the direction vectors of points A1 and A2 is regarded as part of the sphere, and the direction vector of point A1 is the tangent line of the sphere at point A1; 2.2) Divide the arc into several equal parts according to the angle between it and the center of the sphere, and obtain the longitude and latitude coordinates and depth information of each point; 2.3) Re-inject the newly obtained data into the array, overwriting the original array information; 2.4) Repeat steps 2.2) and 2.3) until (A1, A2, A3....A) is completed. n ) to complete all the data.

4. The method for three-dimensional visualization of ocean currents based on moving lines according to claim 3 is characterized in that: In the actual application scenarios of ocean current field visualization, there are two situations: real-time monitoring and historical data presentation. If it is a historical data presentation scenario, the completed data is directly saved to the database for persistent storage, covering the original data information. If it is a real-time monitoring scenario, the data is saved to the database after the next round of data information is received and the collection point data screening and data completion are completed.

5. The method for three-dimensional visualization of ocean currents based on dynamic lines according to claim 1, characterized in that: The step 3) comprises the following steps: 3.1) Count the 3D subspace areas within the current access field of view and calculate the total number of cross-section initial points. If the boundary of a front-end access request is within a certain 3D subspace area, it is counted as a complete 3D subspace area. 3.2) Generate a corresponding number of threads in the program code of the backend server according to the total number of initial points of the cross section; 3.3) According to each thread, set the data reading interval of a certain thread according to the time interval between two collection points; 3.4) Read data according to the time interval, push the data reading results to the front-end program, and generate the moving line through the front-end code; 3.5) Determine whether the last data in the array has been read. If so, return to the first data in the array to re-read and push it to the front-end program; otherwise, end the rendering process.

6. The method for three-dimensional visualization of ocean currents based on moving lines according to claim 5, characterized in that: The step 3.3) is specifically as follows: Assume that the acquisition point times of point A1 and point A2 are time1 and time2 respectively, then the data reading interval is the length of the interval between time1 and time2, divided by the total number of supplementary data points + 1.

7. A three-dimensional visualization system for ocean currents based on dynamic lines, characterized in that: include: Data collection point screening module, used to obtain ocean current field data and screen the collection points; Data completion module, used to complete the filtered data; The data visualization module is used for visualization based on the completed ocean current data.

8. A three-dimensional visualization device for ocean currents based on moving lines, characterized in that: It comprises a memory and a processor; the memory is used to store a computer program; the processor is used to implement a three-dimensional visualization presentation method of ocean currents based on moving lines as described in any one of claims 1 to 6 when executing the computer program.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by the processor, the method for three-dimensional visualization of ocean currents based on moving lines as described in any one of claims 1 to 6 is implemented.

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