The Research And Design Implementation Of Meteorological Facsimile Maps Vectorization

In recent years, the extensive application of Meteorological Facsimile Maps offers a new opportunity to marine career. Meteorological Facsimile Maps are products to show the weather numerical prediction using graphics.It is used completely depending on reader's professional knowledge, even in qualitative analysis. All of these restrict the using in practice of Meteorological Facsimile Maps in the breadth and depth.It is necessary to vectorize the Meteorological Facsimile Maps which can convert the bitmap data formats to the vector data formats. Vectorized meteorological facsimile maps can be used to unite with Electronic Charts Display and Information System(ECDIS) and are convenient for interpretation. Furthermore, it can achieve the transformation from qualitative analysis to quantitative analysis.The basic principle of image vectorization and some existing algorithms are analyzed and ideas for the vectorization of meteorological facsimile maps are put forward first in this thesis.In the stage of image preprocessing, according to the characteristics of the meteor-ological facsimile maps, this paper uses its own method which is the separation of var-ious elements to simplify the vectorization and applies different methods for each differ-ent elements.The improved OPTA (One-Pass Thinning Algorithm) algorithm is used to thin images and to connect isallobars combinng the constraint condition of minimum distance with the constraint condition of minimum direction. The vectorization of isallobars extracts feature points with point-wise tracking and point-wise screening and uses polylines connecting the feature points to carry out curve fitting. It ensures the accuracy of the vectorization and completes data compression.