Scale-driven Adaptive Study Of Geological Map Symbols

With the development of electronic maps,infinite zooming of geographic data on maps has been achieved,but the differential expression of map symbols changing with scale has not formed a systematic study,so that the current map symbols can not reflect the law well that changes of the features with the scale.Therefore,this paper solves this problem through adaptive study of geological map symbols driven by scale,and improves the expression effect of maps.This article relies on the geological industry,through the analysis of the GB958-99 regional geological map legend,and corresponding application,the main research content includes the following three aspects:(1)Driven by scales,first divide the cartographic scale into large scale,medium scale and small scale;and rely on the geological industry,based on the business needs of the geological industry,classify the formation and lithology data to determine the scale of the paper.The map surface depicts the granularity,and the features on the map determine the semantic information of the symbol,so the graphic structure of the symbol is divided,and the adaptive vector model of the geological map symbol driven by the scale is constructed using the idea of the full vector map symbol.At the same time,considering the influence of cartographic synthesis on the type of map symbols after the scale changes,a method is proposed that only changes the type of symbols and keeps the content of the symbols unchanged,so as to achieve the purpose of linkage and differentiation of different scales.(2)The scale changes,the general model response,and then forms an adaptive symbol under different scales,The map symbol formed under the large scale driven is a texture symbol.In this paper,the texture material is subjected to color clustering,texture skeleton extraction and synthesis steps to design the texture symbol filled with irregular primitives;the symbol is made according to the formula and the scale drive is constructed geological map symbol database to store symbols.In current geological maps,when the area of the map is large,more detailed symbols will be used for rendering.In order to better adapt to the industry,this requirement is fully taken care of in this article.While providing the symbols formed by the mapping scale drive,it also provides map symbols that are driven by a larger scale for the large area.(3)Based on the above research,the scale is used as the symbol-driven element,the industry needs are considered,and the feature area is used as the rendering-driven element.Through database constraints,the object-oriented thinking is used to design the class and interface to obtain the symbol to achieve the graphical expression.In this paper,by rendering the designed symbols in the large,medium and small scale example images to feel the overall effect,verify the scale-driven adaptive map symbol model,you can feel the features of symbols expressed in more detail,map is also more specific.