Map Generalization Of Ocean Flow Field Based On Information Entropy

Ocean flow field mapping synthesis is one of the key technologies of electronic chart mapping.According to the characteristics of the flow field and the characteristics of the mapping area,the main and essential data in the flow field are extracted to summarize the flow field.This process is called the flow field.Cartographic synthesis.In the existing graphics comprehensive method,in the process of information compression,the problems of loss of effective information and increase of invalid information are more serious.Therefore,in order to improve the retention effect of effective information,this paper starts with the importance of flow field data,and researches the large data volume flow field feature extraction,the vortex feature extraction method based on angular momentum model,and the multi-attribute decision-making method based on information entropy.Due to the complexity of existing feature extraction methods,the feature extraction efficiency of large data volume flow fields is low.In response to this problem,this paper uses spatial autocorrelation analysis and classification analysis methods to analyze the key attributes of the flow field,such as velocity and flow direction,to obtain flow field data aggregation patterns and research hot spots,and to divide feature areas and assign data point weights according to the clustering results.This method can obtain the hot spot of the flow field research and extract the area boundary while ensuring the efficiency of data processing.Usually the vortex actually exists has irregularities,which leads to the complicated calculation of vortex extraction.In order to efficiently and accurately extract the vortex characteristics of the flow field,this paper proposes a vortex extraction method based on the angular momentum model.Establish an angular momentum model to calculate the approximate vortex core point,calculate the information entropy according to the spatial position of the vortex core point,establish a vector distribution histogram and calculate the vector distribution probability to analyze the difference between the vortex characteristics and other flow field characteristics,and finally exclude the vector distribution dispersion Error zone,accurate extraction of vortex features.Experimental results show that,compared with traditional extraction methods,this method can extract vortex regions and ensure accuracy without complicated calculations,and can be applied to data with different spatial resolutions.It also solves the saddle point when calculating flow field information entropy The effect on the vortex also has a better extraction effect on the weak vortex.This paper optimizes the calculation method of the importance of rough set theory on attributes according to the concept of conditional information entropy,and understands the concept of rough set theory from the perspective of information volume to make its expression more intuitive and comprehensive.According to the new attribute weight calculation method,the attribute weights are obtained,and the data point comprehensive weights are obtained in combination with the data point weights,and the comprehensive work of flow field mapping is completed as a standard.Finally,the comprehensive mapping evaluation of the ocean current field is carried out,and the system thinning and layer thinning methods are compared with the method in this paper.The experimental results show that this paper can retain more effective information with a longer thinning step.The multi-level comprehensive evaluation method of fuzzy mathematics was used to establish a mathematical model to verify the reliability of the method in this paper,and the scientific evaluation of the mapping effect of electronic maps was carried out.