Study On Information Extraction Method Of Coastal Wetland And Analysis Of Changing Driving Factors In Fujian Delta

Coastal wetland is an important part of wetland.Besides its ecological value,coastal wetland also has its specific functions.Coastal wetland is an important place for coastal aquaculture,and it is a habitat for many animals.It also plays an important role in water conservation,coastal protection,pollutant purification and so on.The Fujian Delta is one of the most abundant coastal wetland resources in Fujian province.In recent years,the coastal wetlands in the Fujian Delta have been affected by foreign factors,and the land use situation has changed.Based on this,the monitoring of coastal wetlands by remote sensing can provide reference for wetland protection.Using ZY-3,GF-1 and Spot5 images as the classification data source,the research sample area was selected and the information extraction method of coastal wetland in Fujian delta was explored.The classification experience of the sample area was used to guide the 2015 image classification of the whole research area,and the classification data of the coastal wetlands in 2015 were completed.On the basis of the data of the 2015 classification results,we interpret the Spot5 image of 2005,complete the 2005 coastal wetland interpretation,and supplement the information of two submergence wetlands with low tidal Landsat data,and combine the dynamic degree of land use,analyze the land use change in the coastal wetland of the Fujian Delta from 2005 to 2015,and explore the driving factors for the change of the change.The main contents and conclusions of the study include the following aspects:(1)Exploration of Fujian Delta coastal wetland information extraction method:according to the previous classification experience,combined with the actual situation of land utilization of coastal wetlands in Fujian Delta,the coastal wetlands in Fujian delta are divided into herbaceous salt marsh wetland,river,sea,shallow,mangrove,paddy field,reservoir pond,aquaculture water,non wetland divided into woodland,dry land,unused land and construction.Select the research area,compare the maximum likelihood method,the single level object oriented decision tree classification and the multi level object oriented decision tree classification method,results show that the classification accuracy of multi level object-oriented classification method is high,and the effect of wetland recognition is good.(2)Multi temporal coastal wetland information extraction:the GF-1 and ZY-3 image classification of 2015 in the study area was completed by the multi level object oriented decision tree classification method.In view of the area and distribution characteristics of the area in the Fujian delta,the visual interpretation of the 2005 Spot5 image was completed on the 2015 classification results,and the preliminary distribution data of the 2005 and 2015 Fujian Delta coastal wetlands were obtained.Because the imaging time is not at the low tide level,some of the submerged wetland information is missing.The Landsat image of low tidal level was used to supplement the data of the classification results of the two phases,and the data of the land use distribution in the coastal wetlands of the Fujian Delta were obtained.(3)Wetland change and driving factors:combined with land use dynamics and transfer matrix,the land use change from 2005 to 2015 is quantitatively analyzed.The results showed that:the natural wetland in the coastal wetland of Fujian delta increased 5815.8hm2,and the constructed wetland reduced 18196.49hm2 in 10.The largest degree of land use dynamics is the herbaceous marsh,and the smallest is the pond wetland.The retention rate of herbaceous marsh wetland is low,and the retention rate of tidal flat and construction land is over 80%.The rest exceeds rate of more than 90%,and the overall retention rate is high.There is a transformation between natural wetlands,constructed wetlands and non wetlands.The largest area of constructed wetlands transferred to non wetlands is 14721.57hm2.The changes in the pattern of coastal wetlands were analyzed from three aspects of diseases and insect pests,aquaculture and urban construction,and some suggestions on coastal wetland protection were put forward.