Tianhe Chi

Design and Implementation of Spatial Data Warehouse for China Sustainable Development Information Sharing

In this paper, we introduce how we design and implement the spatial data warehouse for China sustainable development information sharing in detail. First, we present the overall design framework of our warehouse, and give a detailed description about data processing approaches. Then we promote a novel and effective scheme to achieve mass data organization and management and also show web data services supported by the scheme. At last the data storage mechanism and data warehouse management platform are introduced. The design and implement of the spatial data warehouse are very meaningful as a reference to other similar projects.

Design of middleware based grid GIS

Data distribution of GIS has been realized through WebGIS. With the increasing need of data sharing and GIS, WebGIS can no longer meet this need. The applications of grid computing and middleware technology in GIS lay a foundation for the development of middleware grid GIS. Grid GIS not only makes spatial data distribution, also makes the functional services of GIS distribution. This paper focuses on the functional architecture of grid GIS, and brings forward a functional model of grid GIS. GML and middleware are also important factors in the development of grid GIS, GML is the message carrier in the grid of Web.

Research on Sea Digital Map used for Ship Navigation

With rapid development of modern electronic information technique and navigation technique, the Sea Digital Map, presenting sea geographic information and maritime traffic information in digital style, has come into being. It brought birth to a technique revolution in the field of ship navigation, and accelerated the development of the informationalization, intelligentization, and information sharing of maritime ship traffic. Nowadays, Sea Digital Map and its application systems have been the key part in Ship Integrative Navigation and Maritime Traffic Control. This thesis has made a deeply research on the data structure, accessing control, standard map symbol display of the Sea Digital Map which is met with the criterion Lt Military Digital Sea Map for Ship Navigation Exchange Format Gt of Chinese Navy Navigation Guarantee Dept. Based on the data and display separate idea, and from the point of function encapsulated independently, the thesis developed the Sea Digital Map used for Ship Navigation. It is composed of basal platform of Sea Digital Map, GPS interface, AIS interface, B/S and C/S net communication interface and ARPA frame picture overlay. Its a Web Digital Navigation Map application platform made up with the functions of digital map display and edition, route designing, route monitoring, ship monitoring, maritime traffic data analyzing. Sea Digital Map used for Ship Navigation could be used widely in such fields as ship navigation, maritime transaction, maritime safety traffic management, sea function planning management, etc. This thesis gives a detailed introduction about Sea Digital Map used for Ship Navigation from the point of the composition and realizing technique.

An integrated system based on wireless communication technology and mobile GIS

The integration of GIS, GPS, mobile communication technology and Internet brings us a more convenient spatial information service--mobile GIS. Mobile GIS is based on mobile equipments and transmits spatial information via high performance wireless communication net and Internet. As a kind of distributed GIS, it takes advantage of all these technologies to achieve industry informationization and public information services and can provide location based information services anytime and anywhere. This paper discusses key technologies of Mobile GIS and puts forward an integration mode of wireless communication technology and GIS. IMGIS (Integrated Mobile GIS) is a kind of mobile GIS system developed by the authors. Using IMGIS and wireless network, users can enlarge the traditional application areas of WebGIS and make spatial information service become a kind of mobile service. In this article the system structure of IMGIS and the realization of it are described in details. Keywords-gis; wireless communication; mobile gis; integrated gis; spatial inforamtion service

Lake areas monitoring based on unmixing mixed pixels united with double-edge extraction

The major difficulty in monitoring lake areas based on low or moderate resolution Remote Sensing (RS) data is how to improve the accuracy and applicability of unmixing of mixed pixels, considering both the complexity of objects and limitations of time and space. To solve the problem, this paper proposes an efficient model uniting double-edge extraction with unmixing of mixed pixels, the accuracy and applicability of which is attested by computing lake areas of northwestern China using AVHRR images.

Research on key technologies of data management for the sustainable development information sharing system of China

The Sustainable Development Information Sharing System (SDINFO) of China is a distributed information management network system composed of databases of different types. This system consists of one general data center and 19 sub-centers. Housing the information provided by sectional administrative authorities, the system contains 1 TB volume of data that can be shared in 224 fields of 37 categories under 5 major sectors. Of the volume, 30GB can be shared through the central system. This paper introduces the content of those data, then the system architecture, and presents the key technologies to manage the mass and varied data in the Sustainable Development Information Sharing System, which are laid emphasis on. These technologies include multiple resource data standardization and reconstruction technology, heterogeneous databases integration technology, mass spatial data manipulation technology, distributed information publication technology, and information search technology, which are all discussed in details in this article.

Uncertainty in the raster image to vector data conversion of polygon object

In remote sensing image processing, the conversion from raster data to vector data always needs to be made. In previous research of this conversion, researchers mainly focus on the algorithms and efficiency, neglecting the uncertainties in the conversion. This paper reviews the input uncertainty and model uncertainty, and mainly focuses on the analysis of error and uncertainty, together with their propagation in data conversion from raster image to vector. In the conversion, the uncertainty comes from source image data uncertainties, data processing uncertainties and model uncertainties. An experiment was made on analysis of data processing uncertainties in the conversion.