Design and Implementation of Internet Based GIS of Antarctica

The impact of the Antarctica,especially geographic information system,on our future becomes more profound.Compared to the traditional GIS,Internet GIS has the following benefits:Firstly,Internet technology transfers GIS which has only been used by professional to public information system which can be used by everyone who knows about Internet in any way or any time.In other words,it makes GIS enter into everyone.Secondly,it can reduce expenditure in data promulgation and improve geographic data's share extent and avoid data's collection repeatedly by means of accessing data on Internet.Thirdly,it can construct geographic information service net-work via Internet-based GIS technology by means of the facilities of information highway.There-fore,it is an urgent thing to construct a GIS to realize Antarctic data's access,sharing and publishing on Internet. As we all know,the rapid advance of networking and componentization technology is one of the most important characteristics in software development in recent years.Java,being robust,secure,easy to use,easy to understand,and automatically downloadable on network,is an excellent language basis for database applications.What is needed is a way for Java applications to talk to a variety of different databases.JDBC(Java database connectivity) is a Java API for executing SQL statements.It consists of a set of classes and interfaces written in the Java programming language.JDBC provides a standard API for tool/database developers and makes it possible to write database applications using a pure Java API. This paper presents a new GIS——GeoStar software.The main advantages of the software compared to similar softwares are:① An object-orientated spatial data management platform which has high efficiency;② Integration of vector database,image database and DEM database;③ Component GIS;④ Internet GIS designed with Java which provides the method to access,publish and share GIS data on Internet. Besides,it expatiates the characteristics of Antarctic data which has the distributive characteristic containing perpendicular distribution and horizontal distribution and organization of Antarctic data,etc.Homepage data is the description of each web site of Antarctica,which includes hypertext,hypermedia,hyperlink,hyperdocument,video and VRML,etc.Vector data is main portion of the system,which includes water system maps,island maps,contour maps and elevation data,geodesy control points and place name data.Attribute data is stored by RDBMS,which provides the convenient method to refresh and modify.Metadata is referred to quantitative and qualitative description of geographic spatial data and is the data to describe spatial data's contents,defintion,spatial frame of reference,quality,management,etc.Image data is acquired by RS method,which is integrated into vector data. Moreover,the authors introduce the Internet-based geographic information system of Antarctica consisting of Web Server (in China),Multi JDBC Data Acquisition Server,Metadata Server and Multi Database Server.Web Server is in charge of Web services,such as network directory service,user's power management etc.Database Server is in charge of database management and database service,Metadata Server is in charge of metadata management.The rests of the tasks are finished by Client side,such as pan,zoom in,zoom out,etc. Finally,this system includes data manage component,data acquisition component,spatial query component,mapping component,language component,display component and spatial analysis component,etc.which can access and manage multi data source such as Geofile,GeoDB,Arc/Info,MapInfo,DXF and MGE,link with database including Sybase,SQL Server,Oracle,DBase,Access,Foxpro and Informix.Data manage component is in Web Server,which is in charge of creating network directory service.Data acquisition component is distributed on nodes with database Server on Internet,which is in charge of accessing multi data source.Spatial query component is in Web Server,which can be downloaded to Client and run on Client and is in charge of picking up querying, line querying and polygon querying, etc.Mapping component is in charge of thematic mapping and statistics mapping.Language component is in charge of translating different charter set into unicode, so different users can be brow sed in their ow n language.By means of WWW browser, such as Netscape Communicator or Internet Explorer,user can easily start this system.