Ecological Suitability Evaluation Of Urban Constructive Land In Jianyang City Based On RS And GIS

By the efforts of many designers, and the assistance of GIS (Geographicinformation system), it has been developed from simple system of land ecologicsuitability evaluation to an evaluation system of multidisciplinary overlappinggradually. On the other hand, it has been developed from simple land ecologicalsuitability to a幼cultural land ecological suitability evaluation, forestry landecological suitability evaluation, and construction land ecological suitabilityevaluation, etc.The research is evaluation of construction land ecological suitability under thereference of geographical location features of 1ianYang city and other variousenvironmental factors. Construction land ecological suitability evaluation is the earlystage of land design. And it presents ecological suitability of constructive land inurban development, restraining factor and improved methods towards the lands whichare probably to be used in development of urban and rural areas according to natural,social and economical environmental factors.The research builds environmental quality evaluation system of ecologicalsuitability of construction land of JianYang City, according to evaluation indexselection principle of ecological suitability factors, referring to localnatural environment and social economy and combining with definition of landecological suitability. The evaluation system is divided into three layers-the targetlayer, the restrict layer and the index layer, and it selects natural and social factors,such as slope position, slope degree, elevation, geological structure, vegetation cover,annual precipitation, water system, population density and transportation condition tobe evaluation factors in order to build ecological suitability evaluation system ofconstruction land of 3ianYang City.After building evaluation system, the analytic hierarchy process and graphoverlay method are adopted to evaluate suitability of ecological land. Both of the twomethods make full use of the functions of spatial analysis of GIS and processing ofattribute data. What is more, they carry on calculations of overlay analysis, bufferanalysis and attribute data in order to reflect the current situation of ecologicalsuitability of land objectively and accurately. First, analysis procession drawsthematic map of various factors according to selected and evaluated ones. Secondly, itcalculates every weight of every evaluated factor by using analytic hierarchy process.Besides, it calculates the weights through, at last, it carries on graphics overlapping ofevaluating factors to get final complex graph by ARCGIS. That is suitability-leveled zoning map, which divides the ecological suitability of constructive lands intofive grades. Overall, the constructive lands suitable for urban development are fullof potentials in this city while they are restricted by human factors.It is concluded that the suitability of lands is relative but not absolute accordingto evaluate results. That is to say, it depends on many factors, such as capital source,land supply situation, engineering technology qualification, consciousness level oflocal people, development decisions of local government and so on. Scientificmethods should be used to maximize economical benefits and optimize constructionof ecological environment. Also, bearing capacity of ecological environment,utilization status of urban development, balance development of land utilization andecological environment, distribution of economy and other factors should beconsidered as a whole. Finally, scientific technology should be developed in order toreduce the damage to the ecological environment as well as avoid the harm of naturalenvironment for people.As a branch of land ecologic suitability evaluation, ecologic suitabilityevaluation of building land will be the significant basis for development of new zonesand scheme of urban areas. It is right to follow scientific technology development,explore new evaluate methods, carry on suitability evaluations, build a resource-conserving and environmentally -friendly society, and promote theharmonious unification of ecological environment and social economy...