Multi-source Remote Sensing Analysis And Research On Land Type Changes In Cities And Towns Around Dianchi Lake

It is awfully important to do water environment protection and water pollution control work of Dianchi lake,which is the biggest plateau lake around the China.With the rapid development of economy and the improvement of urbanization level,the trban land is continuing to expand.For the urban which adjacent to the Dianchi lake,the expansion of urban land not only promotes economic growth,but also aggravates the pressure of Dianchi lake water protection.Multi-source remote sensing technology has incomparable advantages in the aspect of information identification,dynamic change monitoring and rapid identification of pollution sources into the lake for its safety,efficiently features.Meanwhile,for its powerful spatial analysis and data processing capabilities,GIS makes driving analysis more convenient and reliable.The urbanization speed of the main urban area of Kunming has been slowen down,Jinning district as a representative of the small and medium-sized towns have become the latest expansion of urbanization region.This paper takes the downtown area of Jinning as the research area,based on the Google historical image road network data field survey data of multi-resolution multi-temporal remote sensing image data,the change of urban land use is studied from three aspects: Multi-source remote sensing of urban land extraction——based on multi-source remote sensing images,remote sensing information is interpreted by different classification methods,select the most suitable information extraction technology urban land in the research area.Analysis of spatial and temporal changes of urban land use — — from two aspects of time and space,the spatial superposition and transfer matrix are used to analyze the time change,and the center of gravity shift and landscape pattern index are combined to analyze the spatial change;Analysis of thematic changes of roads and lakeshore belts,considering the geographical characteristics of the study area,a special topic is selected as the road and lakeshore belt to deepen the analysis of its driving effect,and the ecological environment change in the Dianchi lake basin in the lakeshore belt of the study area is analyzed.The following research results were obtained:(1)Research on the technical method of multi-source remote sensing for urban land extractiusin: Landsat8 image and Gf-2 image were used as data sources to extract urban land,and object-oriented,comprehensive decision tree and object-oriented methods were used forclassification and extraction respectively,and precision evaluation was carried out.GF-2classification accuracy is generally better than that of Landsat8 images.The GF-2 data based comprehensive decision tree and object-oriented method have the best classification effect,with a total accuracy of 91.50% and a Kappa coefficient of 0.893.The comprehensive decision tree based on Landsat8 data and the object-oriented method have a good classification effect,with the overall accuracy of 87% and Kappa coefficient of 0.870.Therefore,this method can be used in the study of follow-up experiments.(2)Time-space change analysis of urban land: Considering the time continuity of data,Landsat series images are used as data sources to obtain information on urban land change during the past 27 years.The time perspective: Urban land is expanding year by year,urbanization speed continues to grow,and the change is most obvious in 2008-2017,with a rate of change being 123.44 hectares/year.Compared with other provinces and cities,this stage is still a period of low-speed change.The development of such small and medium-sized towns is still relatively slow,as Jinning;The spatial perspective: the center of gravity of urban land is close to the lakeshore line,and then moves away from the lakeshore line.The area moves south.According to the landscape index,the complexity of the plate is reduced,the urban land planning is gradually improved,the plaque binding degree is increased,and the physical connectivity of urban land is enhanced.(3)Thematic variation analysis of roads and lakeshore zones: thematic variation analysis of roads: the roads variation greatly,the area and coverage rate increase year by year,and the road network is gradually improved;The CA,Pland and urban land usage variation have a positive proportional linear relationship with the corresponding index of road vvariation,and the changes track of the center of gravity of urban land is close to the change track of the center of gravity of the road,which shows that the road has a driving effect on the expansion of urban land use.Lakeshore zone project variation analysis: lakeshore zone within the town land decrease,water body,combined with images and field survey data also can see the shore belt with retreat trend of land reclaimation,based on the geographical location,adjacent to the Dianchi lake Jinning movement to strengthen in the lakeshore zone ecological environment protection,urban land focus gradually move away from the direction of lake strandline,visible lakeshore zone has driven effect to urban sprawl.