Study On The Visual Quality Assessment Of Green Landscaping

With the rapid development of worldwide urbanization and expansion in the fields of industry, energy, and communications, landscape visual environment have suffered significant damage. Landscape visual pollution along with other pollutions poses an increasing threat to man's health, both physically and spiritually. Although green landscaping can not provide materials required to sustain life, it can replace natural environment in part to meet people's physical and psychological needs. There are have been numerous theoretical methods and practices developed and implemented on the landscape visual quality assessment (LVQA) in western countries, and a majority of developed countries have established formal landscape visibility environment assessment institutions. Landscape Architecture of China has a long history and received a worldwide reputation for its abundant traditional aesthetic theories and practical design methods. However, scientific assessment and protection work for contemporary landscape visual quality is a relatively new field. Now, the LVQA is not popular in China because of insufficient recognition for visual environment, lack of evaluation methods, and few legislative protections.Based on the investigating the international theories and methods of LVQA thoroughly, summarizing China's national situation, and considering the existing research supports, "The assessment of visual quality of green landscaping" was selected as the research topic. From establishing a clear understanding of Visual Quality Assessment of Green Landscaping, the feasibility of evaluation methods and techniques was discussed with four practical examples. Moreover, visual quality assessment was used in environmental planning and management. The main contents and conclusions are as followings:(1) Intensively investigate the concept, characteristics and functional meanings of the visual quality assessment of green landscaping. Summarize the theoretical framework and methodology system of LVQA. Among them, the LVQA is divided into expert paradigm, psychophysical paradigm, cognitive paradigm, and experimental paradigm; the two major methods for assessing the visual quality of landscapes are "expert/design" and "public perception-based" approaches. Moreover, this paper made it clear that LVQA has important significance to improve the environment management strategy and promote the comprehensive strategy. (2) This paper chose three representative research objects:urban green landscaping under high-voltage lines, green landscaping in rural residential areas and urban waterfront green landscaping. According to the function of visual environment of green landscaping and the different research objects, the multiple evaluation index systems were established which consisted of the green landscaping visual quality, landscape semantic descriptors and landscape physical components. The semantic descriptors were also applied to study the comprehensive evaluation of green landscaping. Furthermore, we gave some suggestions for future landscape planning and visual resources management. Visual environmental impact assessment should be included in environmental impact assessment.(3) Photos were selected and used in the survey captured the most relevant features of different landscapes. The valuators are mainly college students and general public were also considered. The methodology combined the "expert/design "and "public perception-based" approaches and different evaluation indicators were applied in different research objects. The contributions of the attributes contained in a photo to its overall scenic beauty via correlation, regression and factor analyses. According to the evaluation results, we explored the relationships among public preferences, landscape semantic descriptors and landscape physical.(4) the research findings in four examples had some common ground and they are as follows:the public appears to prefer areas with a greater variety of vegetation and rich colors; areas with both natural features and a selection of human additions (rockery, traditional house, and fountains et al.) received higher ratings than areas with only natural features; semantic descriptors of vividness and distinctiveness proved to be significantly correlated with visual quality of green landscaping; type of vegetation, color contrast and presence of positive man-made elements had significant positive influences on scenic beauty.(5) This paper made such suggestions on perfecting the laws and regulations for landscape visual quality, compiling the guidelines for visual environmental impact assessment, and establishing the interaction mechanism between visual environmental impact assessment and landscape planning and management.(6) Because of limited time and resources, the researchs in this paper are preliminary. More intensive studies should be made in the future:①the theory, methodology and specific evaluation techniques need to be further improved;②The application methods of visual quality assessment are suitable for these four examples, but more integrative cases need to be done to test and verify these evaluation methods due to green landscaping has many types;③this paper did not carry out more researches on different time series and this inadequacy requires a more detailed study;④it is important that the surrounding environments should be concerned when we assess the landscape visual quality;⑤computer visualization technology can be used to appear future visual environments of green landscaping which will be affected by some certain proposed actions, and the visual environment impacts could be evaluated and predicted on the basis of this simulation.