| Visualization of scientific computing is to transform the data of scientific computing into graphics and images,which can show the overall characteristics and local details of the data.Visualization of ocean scalar/vector data is one of the important contents of visualization of scientific computing.As one of the common data types for data visualization,grid data is widely used in oceanography.Among them,unstructured triangular grid can simulate the complex boundary of land and sea more accurately,so the research of ocean scalar/vector data visualization based on unstructured triangular grid has become a hot spot in scientific computing visualization.The main work of this paper is to study the visualization method of ocean scalar/vector data based on unstructured triangular grid.In ocean scalar visualization,we mainly study the visualization of scalar data such as temperature,salinity and sea surface height.In view of the uneven distribution of global ocean scalar values,the direct use of uniform clustering method for visualization will lead to the problem of over concentration of a certain color in some regions.Combined with the characteristics of unstructured triangular grid data structure,this paper proposes a color space mapping method based on K-means++ clustering algorithm to realize the visualization of triangular grid scalar data such as temperature,salinity and sea surface height.In the ocean vector visualization,we mainly study the visualization of flow field.Aiming at the problem of uneven distribution of seed points in flow field caused by unstructured triangular grid,this paper proposes a seed point homogenization algorithm based on triangular grid by combining greedy strategy and information entropy.The area of triangle grid is used to calculate its information entropy value and threshold value.According to the threshold value to decide whether to place seed points in each triangle grid,so as to achieve the optimal effect.In the visualization of flow field,the problem of streamline to land often appears.Aiming at this problem,a particle trajectory optimization method is proposed to improve the accuracy of particle trajectory rendering and realize the visualization of triangular grid vector data such as flow field.The experimental results show that the proposed method has good performance in the visualization of ocean scalar/vector data: for scalar visualization,compared with the linear color mapping method based on equalization,the clustering effect of the proposed method is better,and the visual color changes are more abundant.For vector visualization,compared with the seed randomization algorithm based on triangular grid,the algorithm proposed in this paper has more uniform distribution of seed points,improves the problem that the seed points in the middle of the ocean are too sparse and the seed points on the shore are too dense,and makes the particle trajectory drawn clearer.At the same time,the particle trajectory optimization method proposed in this paper solves the problem of streamline to land,which makes the particle trajectory drawn more accurate. |
