| A coastal zone is the interface that sensitive to reactions such as physical,chemical,biological,and morphological processes.The long-term monitoring and management of coastal zones is quite challenging because of their wide coverage and rapid changes.Also,coastal zones are extremely vulnerable to humanization development(such as urbanization,industrialization,agriculture and aquaculture)and climate changes(such as river discharge,ocean waves,sea level rise,which directly or indirectly affect the quality of human life and the stability of the ecological environment.Thus,coastal zones become the research focus of the scholars,managers and decision makers from various countries.Coastlines and mariculture zones are two typical sea features that are strongly affected by human activities and climate changes.Firstly,coastal zones are places with intensive human activities.Those frequent economic and trade activities have led to continually changes in the functional types of coastlines.Secondly,the industry of mariculture zones is rapid developed promoted by the stimulation of food demand brought by population growth.Therefore,there is an urgent need to conduct the researches of monitoring of typical marine features of the coastal zones,exploring the monitoring methods in-depth and analyzing their temporal and spatial evolution process.These researches will effectively help protect coastal resources,scientifically manage of coastal ecological environment,and promote coastal economics and coastal sustainable development.This paper conducted a series of key technology researches on the automatic extraction of typical coastal marine features based on the analysis of the advantages and disadvantages of using different remote sensing techniques for the surveys and monitoring of typical marine features of the coastal zones.Then,the extraction methods were applied to different study areas,and the time-space mechanism analysis were performed to realize the systematic research on the time-series information extractions and time-space analysis of typical coastal features.The main research conclusions of this paper are as follows:(1)To solve the problems of the ambiguity of coastline features using existing methods and the complexity of coastline features in different environmental backgrounds,this paper proposes an object-oriented idea of automatic extraction and attributes classification of coastlines.This method combines the line and surface by extracting the coastline and classification of the land use types around the coastline,and realizes the automatic segmentation of the coastline and the discrimination of its attributes.The experimental results show that the accuracy of the coastline location extracted by proposed method can reach more than 87%,and the overall accuracy of classification can reach more than 84%.This method is greatly simplified in terms of parameter setting and attributes classification,which is conducive to the operation of the interpreter,and has strong robustness.(2)This paper proposes an object-oriented aquaculture zones extraction method that combines edge features to deal with the recognition problems with unclear features and difficulty in detecting aquaculture zones under the complex seawater backgrounds.The method takes advantage of the high concentration of target chlorophyll in the aquaculture area,combines the idea of image interpretation based on segmentation with the remarkable mechanism based on human vision,make full use of the clearer characteristics of the mariculture area boundary in the 15-30m medium-resolution images,and further improve the extraction accuracy of the aquaculture area.The quantitative evaluation results show that the method in this paper has high accuracy in extracting aquaculture areas.When the seawater background is single,the F-Measure value of this method reaches about 95%.In the complex seawater background,the F-Measure value of this method is about 10%higher than that of the OBVS-NDVI method,proveing the robustness of the proposed method.(3)Based on the above research on automatic coastline extraction and classification methods,taking the Indonesian research area as an example,the analysis and study on the spatio-temporal evolution pattern of different types of coastlines in the region during the 28years was carried out,which filled in gaps in the mapping analysis information in the long-term coastlines of the Indonesian archipelago countries.From the perspective of coastline utilization index,sea-land pattern area indexes,and grade division,comprehensively analyze the changes in the spatial pattern of coastlines and the extent of development benefits.The results show that on a national scale,the total length of Indonesia’s coastline has been increasing in the past 28 years,mainly manifested by the increase in artificial coastlines;on the island scale,the island with the largest increase in coastline development and utilization is Kalimantan.The form of development and utilization is at the expense of mangrove shoreline.On the inter-provincial scale,the province with the largest change in coastline development and utilization is South Sumatra,with the development and utilization index rising from 100in 1900 to 266.43 in 2018;The change trend of the land-sea pattern of the Indonesian coastline is mainly the expansion towards the sea.Among them,the land area of Riau Province has expanded the most,with an increase of about 177.73 km~2,accounting for 23.08%of the country’s land area increase.West Java Province has the most severe seawater erosion.Through the analysis of population and economic data in the same period,it is found that topographical factors are the main constraints for the continuous growth and development of the artificial coastline in the region.(4)The above-mentioned research findings are also used to the study of automatic extraction and monitoring of aquaculture areas in China’s Bohai-Yellow Sea region from 1990to 2018 with remote sensing means,which filled in gaps in the mapping analysis information in the long-term aquaculture areas in China’s Bohai-Yellow sea region.The evolution trajectory,pattern changes,and the extent of development and utilization of aquaculture area were comprehensively analyzed from the perspectives of land use dynamics,center of gravity migration,and Euclidean distance index.The results showed that:During the period from1990 to 2018,the area of aquaculture areas in different provinces in the region has shown an increasing trend.The province with the fastest growth rate was Jiangsu Province,with an increase of 520.34km~2;the migration distance of the center of gravity of the aquaculture area is ranked from the largest to the smallest in Jiangsu Province,Liaoning Province,and Shandong Province.Among them,Jiangsu Province has the largest migration distance at48.78km;discussing the reasons for the temporal and spatial changes of aquaculture areas,it is found that the distribution changes of aquaculture areas in various periods are mainly restricted by the dual factors of local policies and economic development.(5)In addition,GIS technology is used to superimpose and analyze the typical sea features in the coastline zone and sea area functional policy management,which solves the problem of lack of basic data support in policy management formulation and supervision,and the difficulty of combining theory and practice.The results showed that the classification of the different protection levels of the Indonesian island coastline is conducive to the management and control of the coastline;In the past 28 years,the percentage of strictly protected shores in Indonesia has dropped from 74.05%to 67.95%,a decrease of 6 percentage points,and the length has been reduced by 4,997.47km;The evaluation of Shandong Province’s marine functional zone policy found that the promulgation of marine functional zoning has a certain role in promoting the development of marine aquaculture in agricultural and fishery areas.However,during the monitoring period,some areas inconsistent with government planning were also found,among which port shipping areas and marine protection areas are the main areas for the expansion of aquaculture.At the same time,this study found that the experimental area has the phenomenon of marine compound functions combining aquaculture areas and tourism. |
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