CN110706354B - Data organization method suitable for three-dimensional dynamic display of flood risk graph - Google Patents
Data organization method suitable for three-dimensional dynamic display of flood risk graph Download PDFInfo
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- CN110706354B CN110706354B CN201911012019.7A CN201911012019A CN110706354B CN 110706354 B CN110706354 B CN 110706354B CN 201911012019 A CN201911012019 A CN 201911012019A CN 110706354 B CN110706354 B CN 110706354B
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- Y02A10/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE at coastal zones; at river basins
- Y02A10/40—Controlling or monitoring, e.g. of flood or hurricane; Forecasting, e.g. risk assessment or mapping
Abstract
The invention discloses a data organization method suitable for three-dimensional dynamic display of a flood risk graph, comprising the following steps of S1, splitting a flood evolution grid according to a time sequence; s2, for each sub-mesh generated by splitting, if the number of the vertexes of each sub-mesh is greater than or equal to 65536, performing region division on each sub-mesh according to spatial distribution; s3, regarding each sub-mesh generated by the region division as a high-density mesh if the number of the vertexes of the sub-mesh is still larger than or equal to 65536, and further processing the high-density mesh to generate a corresponding simplified mesh; s4, for each grid, respectively storing the grid basic data and the state data at each moment; and S5, performing two-dimensional indexing on the flood evolution grid according to the spatial distribution and the time distribution. The invention fully utilizes the space-time characteristics of the flood risk graph, carries out targeted grid area division, can effectively realize the block loading of data, and reduces the data initialization time.
Description
Technical Field
The invention relates to the field of three-dimensional visualization of flood risk maps in three-dimensional digital earth platforms, in particular to a data organization method suitable for three-dimensional dynamic display of flood risk maps.
Background
The two-dimensional static flood risk graph widely used at present has certain limitations when representing information such as a flood evolution process, arrival time, submerging water depth, submerging range and the like, is not intuitive and convenient enough in representation form, and cannot be continuously displayed particularly in a time dimension. The three-dimensional flood risk graph can dynamically show the flood evolution process in an animation mode, integrates the functions of information query, data statistics, auxiliary analysis and the like, and greatly improves the application value in flood prevention work.
At present, the data organization method of the three-dimensional flood risk graph is less, and the prior art mainly has the following defects: 1. the flood routing grid consists of a large number of triangular surfaces, and a large amount of time is consumed for initialization operations such as reading, conversion and the like in the real-time loading process; 2. for flood routing data with large watershed and high precision, because the number of the triangular surfaces is too large, great pressure is formed on system hardware, and the real-time rendering performance is poor; 3. the data file occupies a large storage space, and occupies a large amount of bandwidth resources during network transmission, so that network deployment is difficult to realize; 4. the data random access efficiency is low, and the flood evolution process is not easy to demonstrate from the specified time.
Disclosure of Invention
The invention aims to provide a data organization method suitable for three-dimensional dynamic display of a flood risk graph.
In order to realize the purpose, the invention adopts the following technical scheme:
the invention discloses a data organization method suitable for three-dimensional dynamic display of a flood risk graph, which comprises the following steps of:
s1, splitting the flood evolution grid according to the time sequence:
s1.1, if the water depths of three vertexes of a triangular surface in a flood evolution grid are all 0 all the time, the triangular surface has no life cycle; otherwise, the triangular surface has a life cycle, the time when the water depths of the three vertexes of the triangular surface are not completely 0 for the first time is taken as the starting point of the life cycle of the triangular surface, and the time when the water depths of the three vertexes of the triangular surface are not completely 0 for the last time is taken as the end point of the life cycle of the triangular surface;
splitting the flood routing grid according to the difference of the life cycle starting points of the triangular surface to generate sub-grids at all times; deleting the triangular surface without the life cycle directly;
s1.2, merging the sub-grids with smaller adjacent time: taking the sub-grid at the first moment as the current sub-grid, and if the sub-grid at the next moment does not exist, directly returning; if the sub-grid at the next moment exists, judging whether the sum of the number of the vertexes of the current sub-grid and the sub-grid at the next moment is less than 65536, if so, merging the two sub-grids, taking the merged sub-grid as the current sub-grid, and repeating the process; if the current sub-grid is greater than or equal to 65536, directly taking the sub-grid at the next moment as the current sub-grid, and repeating the process;
s1.3, calculating each merged sub-grid to obtain the starting point time and the end point time of the life cycle of the sub-grid; the starting point time of the life cycle of the sub-grid is equal to the minimum value of the starting points of all the triangular surface life cycles contained in the grid, and the end point time of the life cycle of the sub-grid is equal to the maximum value of the starting points of all the triangular surface life cycles contained in the grid;
s2, for each sub-grid generated in S1.2, if the number of vertexes is greater than or equal to 65536, carrying out regional division on the sub-grid according to spatial distribution;
namely: dividing a global scope into a plurality of rectangular areas, and setting a number for each area; segmenting the sub-grids with the number of vertexes being larger than or equal to 65536 into corresponding rectangular areas by taking a triangular surface as a minimum unit, and recording area numbers;
s3, regarding each sub-mesh generated by the region division in S2, if the number of the vertexes of the sub-mesh is still larger than or equal to 65536, regarding the sub-mesh as a high-density mesh, and further processing the high-density mesh to generate a corresponding simplified mesh;
s4, for each grid, respectively storing the grid basic data and the state data of each time; the base data of the mesh includes vertex coordinates and triangle face index data; for the high-density grid, the triangular surface index data is coded by adopting an integer type of four bytes, and the other cases are coded by adopting an integer type of two bytes;
the state data of the grid comprise water depth, flow velocity, flow direction and sand content data of each vertex; starting from the 1 st moment of the whole flood evolution time, recording complete state data once every 10 moments, namely the original value of the state data; only relative state data are recorded at the middle 9 moments, namely the relative value of each state data relative to the previous moment; in addition, the first moment of the life cycle of the sub-grid is also recorded as complete state data;
s5, according to the space distribution and the time distribution, carrying out two-dimensional index to the flood evolution grid;
s5.1, firstly, indexing each time of flood evolution by spatial distribution;
s5.2, continuously arranging grids with different precisions in the same area during storage, and using a single index;
and S5.3, indexing the data information at each moment again.
2. The data organization method suitable for the three-dimensional dynamic display of the flood risk graph according to claim 1, wherein: in S3, the specific steps of generating a corresponding simplified mesh are as follows:
s3.1, carrying out priority ranking according to the position and the area of each triangular surface in the sub-grid, wherein the triangular surface positioned at the edge has the highest priority, and the triangular surface with larger area has higher priority; sequentially shrinking the triangular surface with the lowest priority, namely moving three vertexes of the triangular surface to the middle point of the triangular surface and combining the three vertexes into one vertex until the number of vertexes of the whole sub-mesh is less than 65536;
and S3.2, when the high-density grids are stored, simultaneously storing the original grids and the corresponding simplified grids.
The advantages of the invention are embodied in the following aspects:
1. the invention fully utilizes the space-time characteristics of the flood risk graph, carries out targeted grid area division, can effectively realize the block loading of data, and reduces the data initialization time.
2. The invention is designed for real-time rendering, necessary hierarchical optimization is carried out on the high-density grids, grids of corresponding levels can be selected for rendering according to the three-dimensional viewpoint distance, the real-time rendering performance is good, and the user experience is good.
3. The invention effectively reduces redundant information of the flood risk graph in time and space, occupies small storage space and is more beneficial to realizing networked deployment.
4. By means of the coding mode of combining the complete state data and the relative state data, both the sequential access and the random access of the data are effectively considered, so that a user can quickly position to a specified time for demonstration, the operation flexibility is achieved, and the random operation of the user is more friendly.
Drawings
FIG. 1 is a block flow diagram of the method of the present invention.
FIG. 2 is a block diagram of the data organization flow of the method of the present invention.
Detailed Description
The present invention is described in detail below with reference to the accompanying drawings, which illustrate the embodiments and specific operations of the present invention, but the scope of the present invention is not limited to the following embodiments.
As shown in fig. 1 and 2, the data organization method suitable for three-dimensional dynamic display of a flood risk graph includes the following steps:
s1, splitting the flood evolution grid according to the time sequence:
s1.1, if the water depths of three vertexes of a triangular surface in a flood evolution grid are all 0 all the time, the triangular surface has no life cycle; otherwise, the triangular surface has a life cycle, the time when the water depths of the three vertexes of the triangular surface are not completely 0 for the first time is taken as the starting point of the life cycle of the triangular surface, and the time when the water depths of the three vertexes of the triangular surface are not completely 0 for the last time is taken as the end point of the life cycle of the triangular surface;
splitting the flood evolution grid according to the difference of the life cycle starting points of the triangular surface to generate sub-grids at all the moments; deleting the triangular surface without the life cycle directly;
s1.2, merging the sub-grids with smaller adjacent time: taking the sub-grid at the first moment as a current sub-grid, and if the sub-grid at the next moment does not exist, directly returning; if the sub-grid at the next moment exists, judging whether the sum of the number of the vertexes of the current sub-grid and the sub-grid at the next moment is less than 65536, if so, merging the two sub-grids, taking the merged sub-grid as the current sub-grid, and repeating the process; if the current sub-grid is greater than or equal to 65536, directly taking the sub-grid at the next moment as the current sub-grid, and repeating the process;
s1.3, calculating each merged sub-grid to obtain the starting point time and the end point time of the life cycle of the sub-grid; the starting point time of the life cycle of the sub-grid is equal to the minimum value of the starting points of all the triangular face life cycles contained in the grid, and the end point time of the life cycle of the sub-grid is equal to the maximum value of the starting points of all the triangular face life cycles contained in the grid;
s2, for each sub-grid generated in S1.2, if the number of vertexes is greater than or equal to 65536, carrying out regional division on the sub-grid according to spatial distribution;
namely: dividing the global scope into a plurality of rectangular areas, and setting a number for each area; segmenting the sub-grids with the number of vertexes being larger than or equal to 65536 into corresponding rectangular areas by taking a triangular surface as a minimum unit, and recording area numbers;
s3, regarding each sub-mesh generated by the region division in S2, if the number of the vertexes of the sub-mesh is still larger than or equal to 65536, regarding the sub-mesh as a high-density mesh, and further processing the high-density mesh to generate a corresponding simplified mesh; the method comprises the following specific steps:
s3.1, performing priority ranking according to the position and the area of each triangular surface in the sub-grid, wherein the triangular surface positioned at the edge has the highest priority, and the triangular surface with larger area has higher priority; sequentially shrinking the triangular surface with the lowest priority, namely moving three vertexes of the triangular surface to the middle point of the triangular surface and combining the three vertexes into one vertex until the number of vertexes of the whole sub-mesh is less than 65536;
s3.2, when the high-density grids are stored, the original grids and the corresponding simplified grids are simultaneously stored;
s4, for each grid, respectively storing the grid basic data and the state data at each moment; the base data of the mesh includes vertex coordinates and triangle face index data; for the high-density grid, the triangular surface index data is coded by adopting an integer type of four bytes, and the other cases are coded by adopting an integer type of two bytes;
the state data of the grid comprise water depth, flow velocity, flow direction and sand content data of each vertex; starting from the 1 st moment of the whole flood evolution time, recording complete state data, namely the original value of the state data, every 10 moments; only relative state data are recorded at the middle 9 moments, namely the relative value of each state data relative to the previous moment; in addition, the first moment of the life cycle of the sub-grid is also recorded as complete state data;
s5, according to the space distribution and the time distribution, carrying out two-dimensional index on the flood evolution grid;
s5.1, firstly, indexing each time of flood evolution by spatial distribution;
s5.2, continuously arranging grids with different precisions in the same area during storage, and using a single index;
and S5.3, indexing the data information at each moment again.
Claims (2)
1. A data organization method suitable for three-dimensional dynamic display of a flood risk graph is characterized by comprising the following steps: the method comprises the following steps:
s1, splitting the flood evolution grid according to the time sequence:
s1.1, for a triangular surface in a flood evolution grid, if the water depths of three vertexes of the triangular surface are all 0 all the time, the life cycle of the triangular surface does not exist; otherwise, the triangular surface has a life cycle, the time when the water depths of the three vertexes of the triangular surface are not completely 0 for the first time is taken as the starting point of the life cycle of the triangular surface, and the time when the water depths of the three vertexes of the triangular surface are not completely 0 for the last time is taken as the end point of the life cycle of the triangular surface;
splitting the flood evolution grid according to the difference of the life cycle starting points of the triangular surface to generate sub-grids at all the moments; deleting the triangular surface without the life cycle directly;
s1.2, merging the sub-grids with smaller adjacent time: taking the sub-grid at the first moment as the current sub-grid, and if the sub-grid at the next moment does not exist, directly returning; if the sub-grid at the next moment exists, judging whether the sum of the number of the vertexes of the current sub-grid and the sub-grid at the next moment is less than 65536, if so, merging the two sub-grids, taking the merged sub-grid as the current sub-grid, and repeating the process; if the current sub-grid is greater than or equal to 65536, directly taking the sub-grid at the next moment as the current sub-grid, and repeating the process;
s1.3, calculating each merged sub-grid to obtain the starting point time and the end point time of the life cycle of the sub-grid; the starting point time of the life cycle of the sub-grid is equal to the minimum value of the starting points of all the triangular face life cycles contained in the grid, and the end point time of the life cycle of the sub-grid is equal to the maximum value of the starting points of all the triangular face life cycles contained in the grid;
s2, for each sub-mesh generated in S1.2, if the number of the vertexes is larger than or equal to 65536, carrying out region division on the sub-meshes according to spatial distribution;
namely: dividing the global scope into a plurality of rectangular areas, and setting a number for each area; segmenting the sub-grids with the number of vertexes being larger than or equal to 65536 into corresponding rectangular areas by taking a triangular surface as a minimum unit, and recording area numbers;
s3, regarding each sub-mesh generated by the region division in S2, if the number of the vertexes of the sub-mesh is still larger than or equal to 65536, regarding the sub-mesh as a high-density mesh, and further processing the high-density mesh to generate a corresponding simplified mesh;
s4, for each grid, respectively storing the grid basic data and the state data at each moment; the base data of the mesh includes vertex coordinates and triangle face index data; for the high-density grid, the triangular surface index data is coded by adopting an integer type of four bytes, and the other cases are coded by adopting an integer type of two bytes;
the state data of the grid comprise water depth, flow velocity, flow direction and sand content data of each vertex; starting from the 1 st moment of the whole flood evolution time, recording complete state data, namely the original value of the state data, every 10 moments; only relative state data are recorded at the middle 9 moments, namely the relative value of each state data relative to the previous moment; in addition, the first moment of the life cycle of the sub-grid is also recorded as complete state data;
s5, according to the space distribution and the time distribution, carrying out two-dimensional index to the flood evolution grid;
s5.1, firstly, indexing each time of flood evolution by spatial distribution;
s5.2, continuously arranging grids with different precisions in the same area during storage, and using a single index;
and S5.3, indexing the data information at each moment again.
2. The data organization method suitable for the three-dimensional dynamic display of the flood risk graph according to claim 1, wherein: in S3, the specific steps of generating a corresponding simplified mesh are as follows:
s3.1, carrying out priority ranking according to the position and the area of each triangular surface in the sub-grid, wherein the triangular surface positioned at the edge has the highest priority, and the triangular surface with larger area has higher priority; sequentially shrinking the triangular surface with the lowest priority, namely moving three vertexes of the triangular surface to the middle point of the triangular surface and combining the three vertexes into one vertex until the number of vertexes of the whole sub-mesh is less than 65536;
and S3.2, when the high-density grid is stored, simultaneously storing the original grid and the corresponding simplified grid.
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