Urban Green Land’s Suitability Evaluation Based On Multi-factor Comprehensive Analysis Model

Urban green space is a kind of urban land which is used to improve the urban ecology、protect the environment、provide residents with recreational places and afforest and beautify thecity with the ground surface existing forms of vegetation. As a basic part of the natural ecologicalsystem in the city, urban green space plays a very important role in improving the urbanenvironmental quality, maintenance of urban ecological balance and promoting the sustainabledevelopment of cities. Ecological suitability assessment of urban green space provides scientificbasis for urban green space planning and has vital significance for the city’s sustainabledevelopment.This paper summed up the domestic and overseas research about ecological suitability,meanwhile used the multi-factor comprehensive analysis model to probe the urban green land’ssuitability evaluation of Changzhou based on3S technology. The results showed that:(1) Based on TM image, urban green space locations were extracted using random forestmodel. The random forest classification model achieved the optimal effect when the primaryvariable number of tree node was9and the number of trees was889. After the classification theoverall accuracy was92.75%, the kappa coefficient was0.90, the out-of-bag (OOB) errorreached the lowest point (0.07), the urban green space’s user accuracy was90.51%and theproducer’s accuracy was94.51%. According to the test samples, the overall accuracy was about88.79%and Kappa index was0.88.(2) According to interpreting the remote sensing images based on RF model, the authoranalyzed the current land-use of Changzhou. Interrelated analyses concluded that the area ofurban greenspace was415.28square kilometers, accounting for22.29%of the total area of theland in the city, mainly located in xinbei district and the west and south of wujin district. On thebasis of division levels of urban greenland patches, large patches which were358.42squarekilometers accounted for86.31percent of the total green patch area; the average patch area wasproportional to the patch level. Grade-distribution showed that small and medium-sized greenpatches which less than3000square meters accounted for60.2percent of the total number ofpatches of green space, but their area was only5.09percent of the total area of green space; largemedium-sized patches and large green patches with a relatively small number made up5.09percent of the total area of green space.(3) Based on grid units logistic regression model of urban green land’s suitability evaluation,this paper determined that the main impact factors of urban green land’s suitability in this region,including distance to road, elevation, slope, NDVI, and aspect. The most sensitive factor wasNDVI. With Logistic regression model, it assessed the suitability division. The more suitable andhigh suitable regions took up25.63%of the total area, they mainly distributed in the west,southwest, northwest and southeast of Changzhou. These places have fewer human influences, non-intensive road distribution and higher vegetation coverage rate. Unsuitable regionsaccounted for6.76%of the total area, owing to more distribution of urban construction land andwater, these places have higher building density and lower vegetation coverage rate, and theirurban green patch fragmentation is very serious.Based on analysis of Changzhou’s present situation and suitability of green space suitability,this paper proposed suggestions to Changzhou’s green space system layout from three aspects,the coordinated development of urban and rural areas, ecological garden construction andimprovement of ecological green planning system.