Wu Xincai

Development of Urban Geology Information System Based on MapGIS

The main objective of this study is to develop an implemented system based on MapGIS for managing and visualizing urban geology information, such as borehole, remote sensing (RS) data, geophysical and geochemical data-in Shanghai City. More than 20,000 boreholes, 80G byte RS data and other geological data were managed with three levels in the system. For the convenience of sharing information and building 3D geological model, standard forms of borehole and other geological data, such as cross-sections, were proposed. The design of urban geological datacenter is to ensure the possibility of geology information share. With B/S (browse/server) and C/S (client/server) architectures, the software architecture of the system is composed by three sub-systems: (1) The data management subsystem supported by the data center; (2) The geological data analysis and appraisal subsystem running on the intranet with C/S architecture. Most functions of the developed system were integrated in this subsystem; (3) The urban geological data share and information issue subsystem running on the internet. It is built on the basis of Web GIS and provides functions, such as information search, statistical summaries and 3D geological model browsing, which are stored in the data center for the public. As a result, the system makes the efficient management for urban geology information possible and provides a 3D virtual visualization of underground geological environment with 3D geological modeling function.

The Research of the Arbitrary Excavating Algorithm for the Stratum Structure Model

According the research of the arbitrary excavation method for the three dimensional geologic stratum model, we can be used to analyze the inner structure feature effectively in the geological work. This algorithm is based on the three dimensional geological objects represented by TIN structure. And it extracts the two key operating: “the generation of the cross section” and “the partition of geological bodies which is being cut” after the geologic stratum model being cut, and realizes the propose of purpose of the closure and segmentation. Compared with the classical [1,13] algorithm, this algorithm brings some obvious improvements. It converts the complex cutting problems to a serial of simple operations: collision detection, intersection between a line segment and a triangle, triangle mesh reconstruction, the position test between point and curve, surface or polyhedron, etc. And it expounds the excavating algorithm for the stratum model cut by the arbitrary geometric body.By cutting test with some underground geological model of Guangzhou China build with borehole data and crossing section map data, the algorithm successfully solves the problem of three dimensional geological models analysis such as arbitrary cutting, generating fence diagram, foundation ditch digging, pit excavation, tunnel digging and virtual drilling by means of three-dimensional method

Research on the Land and Resources E-government System at City Level Based on Building Platform

At present, the land and resources e-government system are difficult to adapt to changes in requirement, and have too much duplication of similar projects and limited range of application. Based on the thorough study of the building technology, configuration and plugin technology, this paper puts forward a solution to develop a building platform of e-government system, which can reduce the programming requirements for developer, and achieve building e-government system quickly. By analyzing the development model of building platform, the overall framework of building platform is analyzed in depth, at the same time; the researcher illuminates how to build e-government system. Finally, the land registration flow is used as an example to show the use of building platform.

Research on a data exchange center of land resources based on SOA

Spatial data exchange and system interoperate have become crucial technologies in land resources informatization. Due to the land resources data is accessed using a variety of GIS platforms, and the management systems are developed by different development languages, the data exchange model must support platform-independent solutions implemented in distributed heterogeneous environments. This paper proposes for designing a data exchange center by taking advantage of SOA technology and GML standard. The system aims to share and integrate various formats of spatial data with minimal time delay, providing a variety of services for interoperate between different systems. The proposed architecture is applied, as a case study, the data exchange center is implemented in Hunan province. In conclusion, the exchange between Hunan department and Changsha bureau shows that the application can achieve the goal in heterogeneous environments.

Rules-Driven of Dynamic Resources Directory for Land Resources Datacenter

The spatial resources include data resources, function resources and authority resources. In order to realize effective integration and management of the spatial resources under the distributed heterogeneous environment, the land resources datacenter has provided the rules-driven of dynamic directory. The composition operators were constructed by relation algebra operations such as selection, projection and join which were compounded effecting on data (function) units; these formally described and quantitatively optimized the expressions of dynamic directory in terms of mathematics. Based on analyzing access control operation hierarchy, authority-function binding model was abstracted by authority operator to simplify the complexity of authority scheduling and to solve the geographic entities granularity based authority control and cross-region different authorization in land business. Finally, resources directory can provide the configurable and extensible on-demand service and achieve the isomorphism of heterogeneous spatial resources in the scheduling management level.