Methodology Of Visibility Analysis For Huge-sized And Mid-sized Urban Lakes

In December 2013,on the Chinese Central Conference on Urbanization,Chairman Xi Jinping proposed: “Based on the existing landscape patterns and the unique sceneries,the urban areas should be coexisted and inserted into the natural environment.The mountains and hills,as well as the lakes and rivers,should be visible and reachable to the residences,the emotion of nostalgia should also be memorized.” As the proposal demonstrates,the preservations and establishments of visual-spatial connection between the urban areas and natural environments are among the core theses for recent urban construction works in China,which,as a result,the visibility analysis plays an important role as the foundation of this process of visual environment managing and planning.Therefore,this research uses the West Lake in Hangzhou as a case study,exploring the visibility analyzing methodology for the huge-sized and mid-sized urban lakes.The major researching achievements includes the following conclusions:(1)Innovations on landscape visibility algorithms.After reviewing and summarizing the former algorithms for visibility and viewsheds computation,the algorithms for landscape visual sensitivity evaluation,and the algorithms for visual exposure calculation or estimation,a few newly developed algorithms have been completed,including the promoted algorithm for visibility and landscape visual sensitivity computation based on the wide-used algorithm for accumulated viewshed computation,and the novel algorithm for visual exposure calculation,which could be applied to compute the visual exposures for vast amounts of viewpoints in the huge-sized and complicated natural or urban environments.(2)Systemic visibility analysis methodology for the huge-sized and mid-sized urban lakes.The comprehensive and practicable GIS-based method is formed by utilizing the newly developed algorithms for visibility,viewshed,landscape visual sensitivity and visual exposure computation.(3)The visibility analysis results for the West Lake.By applying the visibility analysis methodology explored in this thesis,the visibility,landscape visual sensitivity and the visual exposures of the West Lake are gained,which could be used as the fundamental data for the visual management and city construction for Hangzhou.The thesis is composed with five chapters,and their central points are shown as follows.Chapter one is “Introduction”.In this section,researching background,and researching contents are briefly demonstrated,and the existing literatures,methods and algorithms are carefully reviewed and summarized.Additionally,the researching targets and significance are also included.Chapter two is “Methodology for the Large-sized and Mid-sized Urban Lake Visibility Analysis”.In this chapter,the software platforms,digital modeling methods,and the statistical analysis methods are briefly introduced.Furthermore,the promoted algorithm for visibility and visual sensitivity evaluation is discussed.And the core inspirations and programming process of newly developed algorithm for visual exposure computation is exhibited in detail.Chapter three is “Methodology of Visibility and Landscape Visual Sensitivity Analysis for the West Lake,Hangzhou”.Based on the promoted algorithms for accumulated viewshed computation,the visibility,viewsheds,and the landscape visual sensitivity of the West Lake are computed.In addition,the factors in relation to the visual sensitivity are basically revealed,and the factors in relation to the accuracy of viewshed and visibility computation are also explored.Chapter four is “Methodology of Visual Exposure Analysis for the West Lake,Hangzhou”.Hundreds of viewpoints on the 12 paved road segments around the lake are selected as the researching sites.The visual exposures of five landscape elements for these viewpoints are calculated by using the novel visual exposure algorithms.Additionally,the results of the calculation are compared among groups to reveal the visual-spatial characters of the different road segments.At last,the factors influencing the visual exposure computation are discussed by comparisons among groups.Chapter five is “Conclusion and Outlook”.The significant conclusions and achievements,as well as the flaws of this thesis are summarized.The applying potential of the methodology and future researching plans are also implied in this chapter.There are about 62,000 characters,and more than 80 figures and tables in total.