Research On Key Techniques Of Ocean Information Visualization

An urgent demand for studying and developing theory, techniques and methods for ocean information visualization has been brought up since Data Ocean Project is included in the China's Tenth Five-year Plan and the 2015 national Ocean Science and Technology Development Plan. This paper address three key techniques in ocean information visualization and present the author's study results about them.The first key technique is ocean application oriented visual modeling and radial accuracy testing for middle and large size sample data sets. A new notion, radial modeling accuracy, is brought forward to evaluate excursion of scattered bivariate data modeling quantificationally. Via describing the feature structure of a field as a set of feature points and tracking the moving orbit of them from the original field to the reconstructed field derived from a data modeling, radial accuracy of this modeling is computed. This method can not only describe deviation of features after modeling but also compare the modeling quality of different modeling methods according to radial accuracy.The second key technique is to detect and visualize local bifurcations in 2d time-dependent vector fields. Bifurcation is a key problem in the study of nonlinear dynamical system. Detecting bifurcations by data visualization method can probe into the structural instability in ocean flow directly, and thus helps reveal unsteady processes in the system. We make Hopf bifurcation, an important local bifurcation which can lead to chaos, a research emphasis, and develop a new method which can visualize the evolvement of Hopf bifurcation and also be applicable to other local bifurcations in principle.The third key technique is discrete vector field decomposition. Vector field decomposition is proposed in data visualization area recently. The author first implement the decomposition method and then apply it to feature extraction in ocean flow tentatively and thus provided a new approach to extracting structure features in this kind of flow field.