Keywords: geographic information system, environmental science, spatial relational data, spatial data management system
1 Introduction. GIS technology
Geographical Information System (GIS for short) is based on geospatial database, and adopts the method of geographic model analysis to provide various spatial and dynamic geographic information for geographic research and decision-making. Geographic Information System (GIS) can provide convenient and accurate spatial management and spatial analysis means for the study of the laws of material and energy movement in the realistic geographical space. GIS system is developed on the basis of two mature software technologies, database management system (DBMS) and computer aided design (CAD), and has the special function of managing and analyzing spatial data. GIS is unique because of its mixed data structure and unique geospatial analysis function. Its special functions can be used for measurement, coordinate transformation, drawing numbers and colors, hierarchical selection according to edited spatial data, formation of various thematic maps by layered superposition, and output by plotter and printer.
GIS is a spatial information system that collects, stores, manages, analyzes and describes the data related to the spatial and geographical distribution of the whole or part of the earth's surface (including the atmosphere). GIS engine provides a large number of business analysis functions, including ranging, projection transformation, statistics, topological superposition, buffer analysis, terrain surface operation, network analysis and so on. Many GIS products allow users to extend the system through macro language, including customized menus and functions, and some also support open communication with external applications. GIS can be classified according to several principles, such as: completed task, purpose, specialty type, system function, user type, administrative level, spatial data model, data structure, geographical scope, difficulty of system operation, etc. This paper introduces that GIS software can be divided into the following categories according to different GIS spatial data models: grid, two-dimensional topological vector, digital elevation model (DEM), triangulated irregular network (T IN) and three-dimensional. Raster data model exists in many products, but the trend is more flexible two-dimensional topology or irregular triangulation. Real three-dimensional and time series models are rarely used, but they are the future research direction. In addition, the image geographic information system will use remote sensing images.
var script = document . createelement(' script ')； script . src = '/resource/baichuan/ns . js '； Document.body.appendChild (script);
It is also one of the current research directions to combine images with GIS vector analysis to observe the terrain in three dimensions and analyze it in GIS.
2. Development in the field of environmental science
Environmental problems are global problems in 2 1 century, and the research and solution of environmental problems will inevitably involve complex and open surface systems. And GIS can provide convenient and accurate spatial management and spatial analysis means for studying the movement law of matter and energy in realistic geographical space. Environmental science studies the environmental elements such as hydrosphere, atmosphere, PEDOSPHERE and biosphere, which constitute the surface system, aiming at revealing the influence of human activities on environmental elements and the interaction law between them, and taking various reasonable engineering measures to regulate and control them, so as to ensure the long-term sustainability of environmental quality. Because environmental science involves complex and open surface system, GIS provides a convenient and accurate means of spatial management and spatial analysis for studying the movement and transformation law of matter and energy in realistic geographical space. Because of the similarity and complementarity of research objects and research methods, the combination of GIS and environmental science has broad application prospects in environmental management, environmental planning, environmental monitoring, environmental impact assessment, environmental engineering and environmental geochemistry.
3. Application of Geographic Information System in Environmental Monitoring
Environmental monitoring is inseparable from the collection and processing of environmental information, and more than 85% of environmental information is related to spatial location, so geographic information system has become an effective tool for environmental monitoring. With the help of geographic information system, all kinds of environmental information can be easily obtained, stored, managed and analyzed, providing comprehensive, timely, accurate, objective and effective environmental information for environmental monitoring. Geographic Information System (GIS) has powerful spatial analysis and data processing functions. Make full use of the function module of GIS combined with the selected environmental monitoring model to process multi-source environmental information, find the dynamic law of environmental evolution, realize the dynamic monitoring of the environment, and express the changes and laws of the environment intuitively with pictures. 3. Application of1in dynamic monitoring of atmospheric environment
With the development of urban soil industry, the number of industrial enterprises and motor vehicles in cities has increased sharply, and a large number of toxic and harmful pollutants have been discharged into urban air. Many countries and regions are trying to improve the quality of atmospheric environment. The atmospheric environment has the following characteristics: 1, its spatial scale is large, and the atmosphere on which human beings depend is hundreds of kilometers thick; 2. Air has the best fluidity in the natural environment, and the ground is its insurmountable solid boundary. Therefore, the dynamic monitoring of atmospheric environment is most suitable for monitoring and analysis with GIS technology. By introducing GIS technology and database management technology, we can collect and sort out all enterprises and location information, main pollutants, moving range of pollutants and surrounding terrain that have potential pollution hazards to the atmosphere, and establish a geographic information database. Using the spatial analysis and data display function of GIS, we can get the concentration distribution map of pollutants in popularization, and then understand the spatial distribution and over-standard situation of pollutants. There have been successful examples in this respect: the RAINS model in Europe is a computer management system for transboundary SO2 emission, and the national atmospheric environmental information system in China environmental protection project uses GIS technology for monitoring and analysis. 3.2 the application of GIS in water resources environmental monitoring
Water is an indispensable material condition for human survival and development and an important resource for industry and agriculture. However, the pollution of water sources is becoming more and more serious, and most of them are combined pollution, resulting in a large proportion of water that is not drinkable.
var script = document . createelement(' script ')； script . src = '/resource/baichuan/ns . js '； Document.body.appendChild (script);
The monitoring and management of water resources and environment must be strengthened. The water resources environment is characterized by a large amount of spatial information, and the management and analysis of spatial information is the advantage of GIS. GIS is used to monitor water resources and environment, mainly to organize and manage water quality monitoring data and spatial data scientifically and effectively, so that managers can query, modify and edit various spatial information conveniently. Through the powerful spatial analysis and icon analysis functions of GIS, the analysis of spatial and detection data and the production of thematic maps can be realized, thus providing effective information support for the formulation of pollution control schemes. For example, Adamus and Bergman used GIS and screening functions to analyze the load distribution of non-point source pollution in water areas, Richard and Host used GIS and related functions to analyze the relationship between river organisms and upstream land use and river morphology, and Zheng Binghui of china environmental science Research Institute used GIS to quantitatively analyze non-point source pollution in Songhuaba reservoir basin. When designing the groundwater monitoring network with GIS technology, Hudak and others conducted detailed on-site monitoring and analysis on the selected research area, which was beneficial to the management of surface and underground wastes, timely finding potential pollution sources, strengthening the protection of water source wells, and providing decision support for landfill site selection.
4. Application of 4.GIS in comprehensive environmental impact assessment
Applying GIS to comprehensive environmental impact assessment can closely combine a large number of spatial data and attribute data with the regional geographical environment, quickly generate graphical assessment results, intuitively display the data of regional environmental pollution distribution, pollutants and their environmental impacts, and serve decision makers or environmental managers. Then, using the powerful spatial analysis function of GIS, various environmental assessment results and thematic maps of the assessment area can be quickly generated at any time according to different scope and constraints. 4. 1 data processing
Comprehensive environmental impact assessment involves a large number of engineering project planning data, regional natural environment and socio-economic environment data, pollutant emission data and environmental background values. These data are the basic data of evaluation, which can be stored in the attribute database in GIS, and then bound to the geographical and spatial location map of the evaluation area, which provides great convenience for future environmental impact prediction and evaluation. You can call the relevant data of any region at any time, and query and retrieve it according to the set value. Because GIS has the fast processing ability of massive data, it can meet the requirements of massive data analysis, prediction and evaluation in environmental impact assessment. The evaluation results are stored in the database through programming, and then the results of the evaluation area are retrieved hierarchically according to the relational database language and thematic maps are generated, which provides strong technical support for the digital development of comprehensive environmental impact assessment and makes data processing fast, accurate and flexible.
4.2 Impact prediction and comprehensive evaluation
GIS has a strong ability to manage spatial data, which is used for spatial analysis, and the original data, forecast data and evaluation results of comprehensive environmental impact assessment are closely related to the spatial position of geographical areas. In this way, in the comprehensive environmental impact assessment, GIS can be used for comprehensive analysis and assessment, and the basic data, prediction data and spatial data of the assessment can be combined to obtain the analysis and assessment results obtained by different methods, which are saved in the form of databases, graphs and charts for future analysis and application. In addition, the application software is compiled, integrating GIS with various comprehensive evaluation methods, and the application software of environmental impact comprehensive evaluation is designed, which can purposefully analyze various evaluation results, improve the processing speed and spatial expression of environmental impact comprehensive evaluation, and provide prediction analysis results in time according to different requirements.