The Development Of Engine Of Multisource Spatial Data Interoperability

At present,with much emphasis on GIS spatial data interoperability,some GIS vendors get to provide the support for multisource spatial data,but less for OGC related Web Services.Therefore,it is difficult for users to interoperate spatial data in practice.OGC has already formulated a series of specifications for GIS spatial data interoperability.SFS(Simple Feature Specification),one of them,describes geometry model composed of Point,Line,Polygon and MultiPoint etc and corresponding distribution,store,retrieval and other simple operations,aimed at enabling GIS software designer to use SFS-conformed features through different interfaces such as OLE/COM,SQL and CORBA.In addition,OGC Web Services including WCS,WFS,WMS etc also offer web services specification for spatial data share and interoperability.This paper based on OGC SFS and OWS frame has designed a set of GIS engine of multisource and heterogeneous spatial data interoperability.Combining improved SFS model with raster object model,this engine provides nearly complete vector-raster integration model and support for web data source such as WCS,WFS, and local data source as well.The engine facilitates spatial data retrieval operation without users learning where data sources are and which format they store as.It also adopts the WorldWind Quad-Tree index mechanism as raster index,and QR tree(a kind of hybrid tree with Quad and R tree) as vector index.Meanwhile, some kind of vector index corresponding to the WorldWind Quad-Tree index is proposed in this paper.