Multi-scale two-dimensional Hilbert curve is constructed, and specially the scale dimension is treated as the third dimension. The new structure embodies the multi-level characteristics and overcomes the drawback of Z sequence coding pattern, thus improving the continuity of the curve and advancing the spatial retrieval efficiency. The authors conducted two kinds of experiments based on the quad-tree model to compare the retrieval efficiency of Hilbert curve and Z curve. The consequence indicates that the multi-scale Hilbert curve performs better than Z curve, and the improvement on different data distributions vary from 15% to 30%.

To supplement the deficiency of the latitude and longitude existed as location code, such as complex description, non-regional characteristics and complex computation, a globe spatial grid reference system is constructed based on GeoSOT from Peking University. The grid system, built from a perfect quadtree with one degree, one minute and one second grid, could be fit for air-earth joint action. It designs a simple and practical location coding method, which also supports distance simple calculation. It could realize multi-source spatial data integrated retrieval, and develop methods of efficient code operation, framework of spatial computing, and 3D-earth grid system. Globe Spatial Grid Reference System will definitely play an important role in the future of big spatial data applications.

Considering the design principles that traffic signs is to strongly attract the human visual attention, combining the phenomenon that the retina strongly responds to large contrast visual stimulation, a hierarchy saliency analytic framework based on visual contrast is introduced. The authors propose a multi-cue visual attention model for traffic sign detection in street scene, so traffic sign detection and segmentation problem is converted to saliency object discovery and location problem. Experimental results show that the proposed method is better than typical saliency methods.

Based on GeoSOT-3D, a non-overlapping, orthogonal, latitude-longitude consistent grid in the spheroidal space, a true 3D representation method is proposed. The method includes two steps: subdivision preprocessing and subdivision expressing. The experimental result, obtained from using atmospheric data, verifies the feasibility of the method, and it provides a new idea for the representation of global observation data.

Aiming at unified geospatial location organization and multi-scale extraction problems of global multi-source remote sensing data, a kind of unified location organization method, which adopts the GeoSOT location identification model based on global subdivision grid, is designed. In this method, geospatial regional range and position covered by multi-source remote sensing data are uniformly identified with structured cells, and a high consistent correlation, which exists between the external outline positioning and internal data block structure of remote sensing data and geospatial location, is established. The principle and test analysis show that the proposed method can more efficiently organize and manage global multi-source remote sensing data that belong to a same geographic region.

A mosaic method for aerial video based on the block Harris feature was proposed, which is able to cope with the problem of high computation and low accuracy of the current mosaic methods. This method overcomes the shortages of the traditional SIFT method, since it can save the matching time and improve the accuracy. First, block Harris feature extraction method is used to obtain a better distributed of the feature point. Then, pyramidal Lucas-Kanade algorithm is used to match the feature points. After that, an improved RANSAC method is used to calculate the affine parameter accurately. Experimental results show that our method can do mosaic quickly and correctly.

In order to solve the unified reference and multi-scale problems and orderly store and manage massive spatial data, a new storage and management architecture based on global subdivision theory is presented by taking deficiencies of organization and storage methods for global spatial data. The system architecture is integrated with the framework of global subdivision grid (GSG) , the computer cluster theory, and the space-temporal integration technology. The main characteristics of this storage technology are the storage based on space and each storage node has an accordingly geospatial meaning. The concepts of global subdivision storage cluster, general design ideal and key design of the system architecture are described. The study on cluster storage theory based on the framework of global subdivision will make a solid theoretical foundation for global spatial data storage systems.

In order to resolve the data sharing caused by different code for the same geospatial object and the geospatial object code having no level information, a global geospatial information unique geocode model, GeoDNA, was put forward based on the global subdivision grid and the models architecture to express global continuous and multi-level geospatial information. At last, an example of encoding remote sensing image data was given. The results show that GeoDNA on global geospatial information enhances the information sharing capacity in GIS and improves the global massive data storage and management more effectively, which is of theoretical and applied value in regional emergency response.

The crowd degree of buildings is a very important aspect for the assessment of environmental quality of urban communities. Remote sensing imagery with high spatial resolution provides more detailed spatial information about land covers and makes it possible to assess the quality of communities in detailed scale. Four factors were proposed to assess the crowd degree of buildings based on the combination of high spatial resolution imagery and some fundamental principles including estate and geostatistics methods. Five typical communities in Xiamen City were selected to demonstrate the application of those indices. Results suggested that these indices could describe the building crowd degree from different aspects, and it provided a new approach in assessing environmental quality of community through high spatial resolution remote sensed data.

It is described that how to combine rough set with PCNN (Pulse Coupled Neural Network) to enhance the contrast of a noisy image to make the image clear so that the next image processing is easy. Meanwhile, the rough set and PCNN image enhancement algorithm is brought forward. The results of computer simulations show that noisy gray images can be enhanced efficiently by using this algorithm and image noise is reduced and image contrast is enhanced so that the image becomes clearer. In addition, the enhan cement effects of images based on this algorithm are better than those based on the other usual image enhancement algorithm.

To implement distributed application component and data storage and access on Internet is a keystone in WebGIS research. Based on the concept of metadata, this paper analyzed the disadvantage of present WebGIS architecture, extended the concept of metadata, brought forward program metadata, and provided a flexible configuration mode of GIS components, preferably solved the problem of sharing distributed data and configuring application flexibly.

A total of 42 aquatic particulate samples (suspended matter and < 63 μm surficial sediments) was collected from 11 large rivers in the eastern China. These rivers include, from north to south, the Amur, Nenjiang, Songhua, Ussuri,Tumen, Yalu, Liaohe, Luanhe, Yellow, Huaihe, Yangtze, Qiantang, Minjiang, and Pearl rivers. Contents of both major elements (Al, Si, Ca, Mg, K, Na, Ti, Fe, Mn) and trace elements (Cu, Pb, Zn, Cd, Cr, Co, Ni, V) in the particulate samples were analysed. Based on the data set, to which were added literature data for the Yellow,Yangtze and Pearl rivers,the geographicvariations of river particulate compositions in the eastern China were studied. The results showedthat the Yellow River particulates contained a notably high content of Ca and low content of Al. Except for the Yellow River, Al contents in particulates increased from the northern rivers to the southern rivers, while K and Na decreased. Trace elements were relatively enriched in the southern river particulates. The geographic variations were suggested to be related to the weathering types and geological background within the river basins. The average composition of river particulates in China was then estimated. Based on the Chinese river data from this paper, as well as on the literature data for other main world rivers, a new estimation of the global average particulate composition was reported. Since the earlier estimations on the literature were not concerned with or only concerned with few of the Chinese rivers which contribute a great proportion to the global load of river particulates, this new estimation may be more reasonable.