The new generation of GIS demands the integrated management of vector, image and DEM data. This paper brings forward a vector, image and DEM integrated spatial data model on the basis of the object-oriented idea. It also discusses the implementation method of this integrated spatial database management system. The spatial database management system has been used in the construction of China Spatial Data Infrastructure as the base of a GIS software, GeoStar. It reveals that the system has high efficiency and feasibility to manage national, provincial and city spatial data of multi-scales and multi-sources.

Taking geological exploration engineering as the topic of our research, we presented a hybrid data model integrating vector and raster data, and proposed a sub-model; i.e., a QTPV (Quasi Tri-Prism Volume) model. Based on QTPV, the concept model, logical model and data structure were designed in detail. Modeling, model cutting and partition algorithms on QTPV are proposed. The modeling features of QTPV have been discussed. The QTPV model is more efficient than 3D FDS and TEN in terms of partition, storage volume, modeling ability, and application in Geological Exploration Engineering (GEE). A 3DgeoMV system prototype has been developed based on the proposed QTPV model. A case study has been conducted by using the real borehole sample data from a GEE area in China's Inner Mongolia China. The application shows that the QTPV has the ability to model real 3D in GEE.

It is a period of explosibility information. Especially for spatial information science, information can be acquired through many routes, such as man-made planet, aeroplane, laser, digital photogrammetry and so on. Spatial data sources are usually distributed and heterogeneous. In order to share and interoperate spatial data, federated database is the best resolution. In this paper, the concepts of federated database and interoperability are introduced. Three heterogeneous kinds of spatial data, vector, image and DEM are used to create integrated database. A data model of federated spatial databases is given.

This paper describes a series of tests on the accuracy of DEMs. The effects of 4 factors on DEM accuracy have been tested, i.e. the accuracy, density of source data, the characteristics of terrain surface and the modelling approaches. A large area covered by two 1:10,000 maps were selected for testing. The terrain types range from flat, hilly to mountainous. Various sources (photographs and contour maps) are used and measurement methods employed. From test results, the followings have been found: (a) Source data measured manually from analytical plotters is most reliable as automated measurement using image matching could generate systematic errors; (b) The accuracy of DEMs decreases (or RMSE becomes larger) with an increase in sampling interval and the relationship is linear; (c) The inclusion of feature points and lines improves the accuracy of DEMs significantly, especially when the terrain is rough; (d) Generally speaking, the accuracy of DEMs decreases with an increase in relief, however, it is not always the case and the best results may be obtained in hilly areas; (e) The direct modelling from originally measured data to form triangular network will yield better results than the indirect modelling via a random-to-grid interpolation to form grid network. The difference could be significant if the terrain is rough. From these conclusions, some advice on DEM production could be made as follows: (a) When using automated photogrammetric system for data acquisition, editing by experienced operators should be considered; (b) In hilly areas, photogrammetric contouring can be most efficient methods for DEM data acquisition if analytical plotters are used; (c) Feature points should always be measured and kept in order to reduce the data volume while retaining the fidelity of the DEM; and (d) When terrain surface is rough, triangulation-based methods are recommended.

With the increasing maturity of distributed object technology,CORBA,.NET and EJB are universally used in traditional IT field. However, theories and practices of distributed spatial database need farther improvement in virtue of contradictions between large scale spatial data and limited network bandwidth or between transitory session and long transaction processing. Differences and trends among of CORBA,.NET and EJB are discussed in details, afterwards the concept, architecture and characteristic of distributed large-scale seamless spatial database system based on J2EE is provided, which contains GIS client application, web server, GIS application server and spatial data server. Moreover the design and implementation of components of GIS client application based on JavaBeans, the GIS engine based on servlet, the GIS Application server based on GIS enterprise JavaBeans(contains session bean and entity bean) are explained.Besides, the experiments of relation of spatial data and response time under different conditions are conducted, which proves that distributed spatial database system based on J2EE can be used to manage, distribute and share large scale spatial data on Internet. Lastly, a distributed large-scale seamless image database based on Internet is presented.