Research On Water Pollution Synthesized Evaluation Of Lake Based On GIS

Water deterioration had been a main problem that restricts our urban development. The method of principal component analysis could substitute obviously simplify data structure for original multidimensional comprehensive variable and minimize loss of original data information. The traditional principal component analysis was improved from three aspects included lineal transform of negative index, logarithmic treatment of original index and choosing the evaluation index. Comparing with the traditional methods, it could hold more information of the original index matrix and had much higher contributing rate of the first principal component.The improved principal component analysis was applied to the water pollution evaluation in East Lake and water eutrophication evaluation in Taihu Lake. It had advantages in some aspects such as comparing water qualities of Taihu Lake in the different places and in different times with each other, deciding the weight of index in environmental evaluation and so on.Through corresponding analysis, the mutuality between every polluting factor, every supervised spot and each other could be found out. And finding out the relationship between the overall quality of water and polluting factors could make it more efficient in getting information from original data and representing overall information of the external environment. Using principal component analysis method to classify the five sub-lakes of East Lake, the corresponding analysis chart provided a measure to compare the water quality of each sub-lake. In the process of water eutrophication evaluation in Taihu Lake, the corresponding analysis chart of the relationship among 10 supervised spots and water eutrophication evaluation indexes are created, which was convenient for environment management.Set Hubei province and Wuhan city for example, the number and the area of lakes in Hubei province were gradually reduced. The historical reasons of the lake pollution are filling of mud and sand, inning of the lake quality and so on. For a long period of time, occupying lake nonlicet and deteriorated water quality had badly restricted urban development in Wuhan city. The history vicissitude of East West Lake Country from 50's to 80's was displayed in a visualization model. The principle in environmental planning was suggested that should adjust measures to local conditions, purify the water in East West Lake and restore the zoology.With the development of GIS, the contents and the methods in water pollution analysis had been modernized, deepened and widen.Based on the technology of GIS, an overall environmental quality evaluation model was put forward with combining three tools of Visual Basic, MapObjects and MATLAB. The application compiled in this method was efficient and integrative. And the process could be designed simplely and tied up little memory. The system also could provide a series of environmental system models, which have abilities of management, input/output, spatial analysis and assistant decision-making. Set pollution evaluation in the sub-lakes of East Lake for example, based on VB? computeing and analysing were carried out with improved principal component analysis in MATLAB 6.5, then a water polluting map was outputed by MapObjects 2.0. So the overall water quality evaluation could be implemented in the system of GIS, which could provide service for the environment manage department.In order to realize visualization of the water pollution synthesized evaluation result, based on GIS, the universal Kriging interpolation method could change the values of observation spots to the values of a region. In the paper, the steps of evaluation were described, and the principle and operation process were concretely discussed. Through the universal Kriging model in Arclnfo, the water pollutants and evaluation results interpolation map could be obtained. When the dates are enough, the map could reflect the reality in environment, and it was very important for decision-making of environmental government.In order to the sustainable development in a district, it was indispensable to build an effective environment management to systematically, sustainly and actively intervene the external environment. It should also contain how to choose the optimum criterion of evaluation on environment, society and economy. In an Environmental and resources' information system, people could examine and modify the information quickly, evaluate the influence of a project, and then improve on criterion and policy, which was ready to be carried out correctly.GIS was introduced to environmental evaluation, planning and management. Based on the technology of GIS, the structure and function of a environmental and resources' information system were given and discussed, In the information system of environment and resources, three aspects include the sources of data, the organizing of spatio-temporal data and the detection of environmental changes were stated, dynamic environmental planning process was concretely analyzed. And some advice about establishing a real time environmental and resources' informationsystem and expectation of it were presented. Environmental management could be improved efficiency by combining the GIS and multiply objects decision.In addition, another way of applying the improved principal component analysis was studied. Aiming at the characteristics of atmospheric environmental quality in a region, logarithmic principal component analysis was applied to obtain the weight of index in environmental evaluation. The fitting gray association analysis was used in the evaluation. This method could avoid the weigh decision, which was always influenced by subjective factor. The evaluation process could obtain the grade of atmosphere and the rank of each supervised spot. Comparing with the synthesized index method, it had precision and impersonality.At last the status of GIS in environment management was synthetically commented on. Now GIS had been the mainframe and integrant technology of the research on many environmental problems. From confirming the object to obtaining the data, confirming object and outputing results in visualization, GIS combining with all kinds of research methods and technology could accomplish various evaluations and planmngs on environment. The paper also discussed the structure and function of an environmental and resources' information system. Environment information system based on GIS could support various plannings and evaluations of environmental projects, at the same time it supported quantitative and qualitative analysis. It could deal with non-spatial and spatial information and then simulation movement of environmentThe application of GIS technology in environment evaluation and management certainly will promote and boost the huge improvement on environment preservation.