Characteristics And Dynamic Changes Of Natural Tourism Resources Based On 3S Technology In The Pearl River Esturary Island

The 21^st century is the century of ocean, and Island is the bridgehead for human development and utilization of marine,while tourism is an important part of the island development. Moreover, the identification and evaluation of natural tourism resources are important island tourist basis and source, it has great significance for island conservation and tourism development. In addition, the Pearl river where have many islands has great loacation advantages, so tourism have broadly development of prospects. But it is low for development and utilization of island tourism resources yet, because of many natural tourism resources to be excavated, to be used and to be developed. Therefore, it is particularly important for research in the type, size, quantity and evolution of spatial structure of the island natural tourism resources in Pearl River Estuary. In this paper, the study area is the island group of Lingdingyang (Qiao Island, Longxuedao, Weiyuan Island, Neilingding Island, side entrances Island). By the TM, SPOT image data of 1990, 2000, 2006 and other supporting data, through analyzing the spectral characteristics of the image, based on the classification system of ntural tourism resources, using the method of combining decision tree classification and supervised classification, the island natural tourism resources could be classified, and with the GIS spatial analysis techniques, the number of each island nature tourism, spatial structure evolution etc. are depthly studied in study area. Apart from this, according to three-dimensional model, interpretation results of the natural tourism resources, and historical documents, analysising the characteristics of study area's natural tourism resources.The main results obtained are as follows:(1) Lingdingyang island group's natural tourism resources are two major categories: One is the landscape of beach coast, bedrock coastline, mangrove, common woodland, water scenery which natural tourism resource has significant changes in short term; The other is the landscape of convex peak, isolate peak, rock holes and caves, sea, wildlife habitat, astronomical observation area which natural tourism resource has not significant changes in short term.(2) The number, scale, dynamic changes of islands nature tourism in the study area show as follows: Firstly, because of human activities intervention, Pearl river island's shoreline overall show a trend of rapidly advancing to the sea, and the island's total area have increased between 1990 and 2006. Secondly, the total length of shoreline of each island, except Neilingding island, have increased. From 1990 to 2006, the length of bedrock coast reduce 14.50km, and the rate of average annual decline is 0.86km/a; With the exception Qiao island, sandy coast's amplitude is the smallest in the four major types of coast, and basically were tested to decrease. Thirdly, in 16 years, the landscape of mangrove is the only one type of a natural tourism resources landscape which is increasing year by year in the three categories; While other types of natural tourism resources landscape can't reflect specific changes in every island. On the whole, natural water show the trend of growth firstly and reduce lately, howere, the general forest landscape shows contrary. Between 1990 and 2006, from the situation of each island, water scenery is reduced in Longxuedao; In Weiyuan island, mangrove landscape was growing up in recent years, so the area is very small, only 0.0443km²; General forest landscape was decreased and then increased; Water scenery was decreasing. In Qiao Island, mangrove landscape was rapidly increasing year by year, the growth rate is 0.3491km², it is increase of 5.5857km² in 16 years, while general forest landscape has decline by the rate of of 0.4975km² in each year, and water scenery has hardly changes; In Hengmen island, water scenery has increase by a rate of 0.2398km² / a and has small changes. In Neilingding Island, all types of the natural tourist landscapeare very small amplitude, and the general forest landscape was slowly decreasing at an average annual rate of 0.0436km².(3) The natural tourism's landscape spatial structure of dynamic evolution results in study area's shown as follows: From 1990 to 2000, general forest landscape and water scenery are decline because of conversion of building land and other landscape; Mangrove landscape is increase from the general landscape, building land and other landscape. Between 2000 to 2006, the increase of general forest landscape and mangroves landscape are mainly from building land and other landscape; Water scenery is reduced because of conversion into building land and other landscape.(4) Using topographic map, through vector and a series of GIS technology to generate DEM and 3D model, it is showing that the natural tourism resources landscape of Lingdingyang island group have Complex and varied topography, beautiful scenery, unique island species, pleasantly ecological environment. it is a ideal area for Scientific exploration, tourism and observation of weather and astronomy.