Spatial-temporal Changes Of The Coastline In Five South Island Of Long Island In Recent Three Decades On RS And GIS

National Island surveillance and monitoring system is to strengthen the regulation of water,vegetation,coastline and development and utilization of the island.Island Coast monitoring is one of the most important tasks.Long Island county is one of the 13 major island counties in China,and it is an important tourist island in the North,whose development of coastal zone is significant.The research on the monitoring and analysis of the coastline is of great significance for the management and protection of the sea island coastline.In this paper,based on Landsat MSS/TM/ETM+/OLI images,google images and one chart of Five South Island of Long Island,the coastlines of 4 periods(1982,1995,2006,2015)were extracted with GIS and RS technology,the position,length,distribution of which were analyzed.1.This paper classified the shoreline into rocky shoreline,sandy shoreline,muddy shoreline and artificial shoreline.Combined with field survey data,in terms of color texture and the adjacency relations,we established interpretation signs as well as principles of 4 types of shoreline in Five South Island of Long Island.2.A statistic of the distribution of shoreline in different time was made in terms of the length,type and land area.The results showed that the length of shoreline in Five South Island of Long Island increased 9.54 km with an average speed of0.54km/a and the trend is toward sea.The change of artificial shoreline is most obvious with an average speed of 3.21%.Rocky shoreline and sandy shoreline suffered the most serious loss with an average speed of-0.49% and-0.23%.3.Based on the type of shoreline changes and the rate of shoreline changes,according to the field investigation and related data,the changes of shoreline of Five South Island of Long Island were discussed from two aspects of natural factors and human factors.The results showed that the changes of the coastline of Five SouthIsland of Long Island are mainly influenced by natural factors and human factors,among them,human factors are the main reasons.The natural factors include sea-level change waves tides and shoreline erosion;human factors including the construction of ponds,salt pond bank port,sea reclamation etc..4.South Changshan island is a relatively active island for human development activities.Typical coast sections of west Island of Long Island,whose development are frequently active,were selected for further analysis.The results turned out that: in the past 30 years,under the combined effect of the natural factors and human factors,the length of shoreline in west Island of Long Island increased 2.70 km,and the trend is toward sea.The change of rocky shoreline and sandy shoreline is more obvious with an decrease of 1.76 km and 1.96km;The silt coastline is all converted into artificial shoreline.