Zhenjie Chen

Study on the complex network characteristics of urban road system based on GIS

Urban road system is the basic bone of urban transportation and one of the most important factors that influent and controls the urban configuration. In this paper, an approach of modeling, analyzing and optimizing urban road system is described based on complex network theory and GIS technology. The urban road system is studied on three focuses: building the urban road network, modeling the computational procedures based on urban road networks and analyzing the urban road system of Changzhou City as the study case. The conclusion is that the urban road network is a scale-free network with small-world characteristic, and there is still space for development of the whole network as a small-world network, also the key road crosses should be kept expedite.

Bivariate Moran spatial correlation analysis between zonal farm-land use and rural population distribution

The relationship between human beings and the earth is one of the important aspects in geographic research, so the study on land use should be focused on the interactions caused by the relationship between human beings and the earth. The author begins with the current land use in the study area, and zonal farm-land use and rural residential population data can be spatialized on the map and reclassified into the grid, according to the results of geostatistcal analysis. Based on the spatialized results, using bivariate Moran indices, a correlation analysis between these two factors and the statistical test should be performed, and the results can be visualized by GIS methods. What has been showing in this research is that, comparing with classical correlation analysis in normal statistics, spatial correlation analysis can be more exact in theory and more available in application.

A fast preprocessing algorithm for massive MODIS 1B data

MODIS 1B data preprocessing consists of bowtie effect elimination and geometric correction. The paper proposes a fast preprocessing algorithm. First, partition the input image into small sub-images without bowtie effect. Secondly, do geometric correction to each sub-image. Finally, mosaic each sub-image in the output coordinate system and eliminate the bowtie effect in the process. The proposed algorithm shows both a better geometric performance and faster preprocessing speed. For the massive MODIS 1B data preprocessing, a parallel preprocessing method based on this algorithm above is further proposed. Analysis shows that real-time preprocessing for massive MODIS 1B data can be realized by the parallel algorithm.

GIS based quantification method of spatial competition

In this paper, the problem of quantification of spatial competition is solved from three aspects: quantification of spatial competition potency, spatial competition relationship, and spatial competition intensity. In quantification of spatial competition potency, traditional evaluation method and Geographical Information System (GIS) spatial analysis technique are combined for evaluation. The influence factors of spatial competition potency are divided as three categories: limiting factors, characteristic factors, and ordinary factors. Thus, synthesis appraisal is employed to analyses spatial competition potency for all geographical entities in evaluation area. At the time of construction of spatial competition relationship model, the gravity model is referred. Nevertheless, some parameters of traditional gravity model are endowed with new meaning: using spatial competition potency of geographical entity to replace the quality, and using accessibility to replace the distance. The process of estimating spatial competition intensity of one point in spatial competition area can be finished through the following three steps: computing spatial competition intensity between each two geographical entities around the point, comparing all spatial competition intensity, selecting the maximum spatial competition intensity as the spatial competition intensity of the point. In order to verify feasibility of the method, rural settlements in Tonglu County are selected as test objects.

The study on adaptive spatial sampling used in allocation of housing price monitoring sites -Taking Wujin section of Changzhou city as an example

In recent years, the Chinese government has attached great importance to the increasingly upward trend in housing price and many regions have developed the monitoring and reporting system of housing price. However, the factors which influence the housing price is so complex that traditional sampling approaches used in the land price monitoring could not play well in housing price monitoring. By analyzing the disadvantages existed in classical spatial sampling and specific characteristics of housing price, taking the dwelling houses in Wujin section of Changzhou city for example, the author brought the adaptive spatial sampling to the allocation of housing price monitoring sites. Through the experiments, we could come to the conclusion that based on spatial-relative matrix, through comprehensive analysis, spatial adaptive sampling would lead to the samples that are representative both on special attributes and spatial location. Finally, the paper also discussed practical approaches that may work to improve the efficiency of adaptive spatial sampling in further study.

Research on the new route choice method of main optical cables based on Dijkstra algorithm: a case study of Guanyun County

Up until now, the optical cable network has covered many cities of China. However, there are still so many middle or small sized cities which are not connected to the grid backbone optical cable network of the country. It is urgent to connect these middle or small sized cities into the backbone optical cable network of the country as soon as possible. However, up until now, little work has been done to find a better way for route choice of main optical cables, including those based on GIS methods. This paper proposes a new method for route choice of main optical cables, i.e., the method for route choice of main optical cables based on Dijkstra Algorithm. In this paper, a model for route choice of main optical cables is built, the influencing factors are chosen and quantified according to the specific situation of Guanyun County, and the route of the main optical cables of Guanyun is chosen and drawn on the map. The result shows that the method proposed by this paper has more potentials than the traditional method used in Guanyun County.

A weighted Euclidean distance method for rural settlements traffic location evaluation

Traffic location is one of the most important factors which affect the development of rural settlements. However, there is no effective method to evaluation traffic location of rural settlements at present. Focusing on large numbers of scattered rural settlements with complicated and fragmentized traffic networks, a weighted euclidean distance method for rural settlements traffic location evaluation is put forward in this paper. In order to differentiate the affection that different levels of roads put on rural settlements, roads are sorted into two classes: the level-roads (such as national and provincial roads, county and town roads) and the village-roads. Then the total quantized value of traffic location of rural settlements, obtained by weighing traffic location quantized values on different road levels, was calculated by GIS spatial analysis module. This method was put into practice to analyze the traffic location of Tonglu County, Zhejiang Province, which showed that it has obtained a fairly good result on the evaluation of the traffic location of rural settlements.

Analysis and preliminary design of Kunming land use and planning management information system

This article analyzes Kunming land use planning and management information system from the system building objectives and system building requirements aspects, nails down the systems users, functional requirements and construction requirements. On these bases, the three-tier system architecture based on C/S and B/S is defined: the user interface layer, the business logic layer and the data services layer. According to requirements for the construction of land use planning and management information database derived from standards of the Ministry of Land and Resources and the construction program of the Golden Land Project, this paper divides system databases into planning document database, planning implementation database, working map database and system maintenance database. In the design of the system interface, this paper uses various methods and data formats for data transmission and sharing between upper and lower levels. According to the system analysis results, main modules of the system are designed as follows: planning data management, the planning and annual plan preparation and control function, day-to-day planning management, planning revision management, decision-making support, thematic inquiry statistics, planning public participation and so on; besides that, the system realization technologies are discussed from the system operation mode, development platform and other aspects.

Design of spatial sampling in setting monitoring sites of residential land price

Neither Random nor stratified sampling can reflect the Dependence among land-price monitoring. Hence, based on Semi-variogram and analysising the anisotropy of different sites of land-price, some useful references are provided. Systematic unaligned sampling with a grid cell size of 1000×500 m was chosen on the basis of semi-variogram analysis, and the length of side is equal to 1/2 of range. At last, part region of the Changzhou city is selected as a study area to examine this method.

Multi-flow direction algorithms for extracting drainage network based on digital elevation model

A set of multi-flow direction algorithms for extracting drainage network form digital elevation model (DEM) based on ground water overflow model is introduced. As single-flow direction algorithms, the algorithms perform some tasks as following: depression identification and treatment; relief increment of flat areas; flow vector determination and drainage network. But in the flow vector determination process, we use multi-flow direction algorithm. We extract drainage network form a set of digital elevation model in Changsha, Hunan Province using this method to test these algorithms. The experiment result shows that these algorithms are efficient and avoid parallel currents, the shortcoming of single-flow direction algorithms.