The Research On The Evaluation Of Map Carrying Capacity

With the advent of the information age,the development and application of information technology has become more and more widespread.Maps are one of the effective forms of information expression.More and more applications and researches are based on maps.The evaluation of the quality of cartography is particularly importantly,the evaluation of map quality can not only measure the outcome of a map,but also can adversely affect the process of cartography,making the final result develop in the best direction.The evaluation of map quality is generally based on the evaluation of its expression content.At present,the map content information is expressed by the map carrying amount and the map information amount.The carrying amount considers the density of elements in the map,and the information amount is based on the map information theory to measure the content of the map expression information.As a basis for the evaluation of map quality,there is no quantitative expression and evaluation of map contents.In order to quantitatively measure the expression of map elements,this paper introduces the concept of map carrying capacity to evaluate the map quality.The map carrying capacity describes how much content of the feature expression is put in a range of maps of a certain size,and through the evaluation of the map carrying capacity of the map,it is determined that the map element is suitable for the map expression in a certain range and is in conformity with the human acceptance scope.This article will take the map carrying capacity as the research object,the main work carried out is as follows:(1)Explaining the main form of map transfer information content is through map language.The composition of map language is symbol,annotation,and color,and the visual variables that express map elements are analyzed.At the same time,the concept of ecological carrying capacity is analyzed and the indicators and methods for assessing ecological systems based on ecological carrying capacity are summarized.Finally,the concept of map carrying capacity was initially proposed.(2)Combining with the theoretical basis of the appeal,the analysis and summarization of the map carrying capacity consists of symbol carrying capacity,annotation carrying capacity and color carrying capacity.In order to quantitatively express the carrying capacity of the map symbol,this article uses the full vector symbology system to analyze the visually transmitted information content of the symbol.The annotation and color are analyzed through its own visual differences.In the end,two indicators of the area complexity of the map elements in the map are summed up to formulate the expression formula of the carrying capacity of each element on the map.(3)Analyze the process and methods of map quality assessment.Map carrying capacity is used as the research object of map quality evaluation.Use the comprehensive analysis method to construct the map carrying capacity evaluation model of the map with symbolic carrying capacity,annotation carrying capacity and color carrying capacity as indicators,and train a large amount of data to give relevant parameters in the model.(4)Select a standard 1:200000 regional geological map,use the map carrying capacity evaluation model to analyze and evaluate it,and give appropriate opinions based on the scores of the given indicators.