Exchange files of geographic incremental updating information based on XML

With the enrichment of products and applications of geographic information, updating of geographic information becomes more and more important. The future geographic information services will be ldquoon demand and timely updatingrdquo. We need high frequency of updating with geographic information, which make the incremental updating or change-only updating to be the novel and mainstream method. Incremental updating detects the difference between different version data sources in the master database and only records the changes information of geographic features and the corresponding characteristics. We deliver the incremental information to client users with differential files to fusion with client database. Scarcity of transmission and exchange of updating information results in the difficulty or inconsistence of updating with spatial database, and a very small change may replace the whole database. We utilize the extensible markup language (XML) to express the incremental information about geographic features because of its standard, openness, readability and flexibility. The paper will define the XML schemas to represent the differential spatial data. Incremental updates with XML provide minimal, structural and detail updating information to the client users, and the users can parse the exchange files to update and upgrade their own database conveniently and consistently. Also the XML exchange of incremental geographic information can satisfy the use-defined demands to implement custom updating. We illustrate the mechanism of share and interoperability with XML updating exchange. Incremental updating with XML exchange will become the commonplace method of updating with GIS database, which provide the novel approach for updating with internet and application of embedded system.