Research On Planar Vector Field Feature-based Visualization And Multi-Variable Data Visualization

Visualization in Scientific Computing (ViSC) is a new subject that was brought forward and developed rapidly in the late 80's. Now it has been widely used in the fields of medicine, geological survey, meteorological report, molecular biology, computational fluid dynamics and finite element analysis, etc. It also attracts more and more attention.Planar vector field visualization is one of the most important parts of ViSC. With the development of scientific technology, the relevant fields are more and more wide, the objects are more and more complicated and the amount of data is more and more large, traditional planar vector field visualization methods can't be satisfied, so feature-based visualization was brought forward. It overcomes the traditional visualization methods'disadvantages and can discover important structures and interesting regions of vector field, so can visualize the most important parts of vector field. By this means, irrelative data is removed from the useful data, so data amount is reduced, and sometimes even can get quantitative description of feature. For large number of data, the feature-based method is a necessary choice.This paper addresses the summary and comparison for the current development of planar vector field visualization, and introduces the topology analysis which is new technique to globally visualize vector field, and it can concentrate on important structures and interesting regions of vector field; the paper also puts forward and implements angle function method for fast detection vortex core region in planar flow field, angle function method is acquired through converting the vector direction around a sample point to a value according to a certain formula, and the function value reflects the change degree of the vector direction around a sample point. The smaller the function value is, the greater the change is. So, the greatest change point is the minimum, i.e. vortex core point.Multi-variable data visualization is complex and is always the focus of vector field visualization. This paper addresses the primary research of applying multi-variable data visualization to physical oceanography and implements the automatic ocean water mess analysis and visualization by applying multi-dimensional transfer functions method to ocean sample data.