Spatial Seamless Data Organization of Large-scale Image Database

At present,digital orthoimages and orthoimage mosaics are playing an increasingly important role throughout the entire geoinformation domain.Especially after the term of digital earth is put forward,digital orthoimages become the main content of digital earth.Orthoimages offer an ideal combination of high information density,broad area coverage,economical and quick acquisition and production.Because every orthoimage covers relatively small area,using it in broad area is inconvenient.Certainly,several orthoimages in which users are interested can be mosaiced into one big orthoimage,but it is still inconvenient for users to access and process.If digital orthoimages are efficiently managed by image database,it will be convenient for users.As China is a big country,the georeference of digital orthoimage is based on Gauss planar coordinate.As far as the image database of national or provincial level is concerned,the coordinate origin of digital orthoimage is different due to the belt-divided projection.Take Guangdong province of China as a sample,the whole province is divided into three projection belts,every belt has its own coordinate origin,the georeference is different and the distortion of neighbor map in two belt edge is very large.Thus it cause the problem of image data seamless organization.This paper analyzes the spatial reference characteristic of digital orthoimage and it causes the problems of the foundation of large-scale seamless image database.On the basis of that,belt-divided storage mode and over-belt algorithm is put forward in mass image data management.Through experiments,it proved the scientificity,validity and practicality in the image database of provincial or national level.