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  • 2011 Volume 13 Issue 2
    Published: 25 April 2011
      
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  • ARTICLES
    Analysis and Prospect on the Prediction Methods of Ground Subsidence in Mining Area
    CHANG Zhanqiang, GONG Huili
    2011, 13(2): 151-156. https://doi.org/10.3724/SP.J.1047.2011.00151
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    The ground surface subsidence due to underground mining of mineral resources is a kind of serious environmental issues over the world, which all the countries with abundant mineral resources are currently confronted with. China is not an exception. With the sharp increasing in mineral resources consumption, this issue will inevitably become more and more severe in the future. In order to greatly reduce the damages induced by ground surface subsidence to the infrastructures and natural environment, it is very important to predict the ground surface subsidence precisely. In the present paper, the authors, first of all, made a systematic and comprehensive analysis on the characteristics and applicability of the major ground subsidence prediction methods currently used at home and abroad. Then, according to their applicability, the authors suggested that the major ground subsidence prediction methods should be divided in to two categories:(1) the prediction methods on spatial domain distribution; (2) the prediction methods on the temporal domain variation. In addition, several feasible and significant directions in the investigation of the ground subsidence prediction were put forward, including (1) on the ground prediction under the concrete circumstances of geology and mining; (2) on the unification problem for the spatial distribution and the temporal variation in the prediction of the ground surface subsidence; and (3) on the integration problem of ground temporal subsidence prediction and field monitoring. Finally, the authors conducted the prospect on the prediction of ground surface subsidence, in which the cooperation and supplement between the prediction methods of ground surface subsidence and the advanced modern space Earth observation monitoring techniques, such as Interferometric Synthetic Aperture Radar and Global Positioning System were emphasized and expected to substantially improve the prediction accuracy of ground surface subsidence and utmost reduce the damages induced by underground mining of mineral resources. Along with the continuously increasing demands for mineral resources, the investigation on ground surface subsidence prediction is expected to play a more important role in the protection of ground surface facilities and natural environments in the future.
  • ARTICLES
    The Effect of Terrain Heterogeneity on Topographic Wetness Index
    MA Jianchao, LIN Guangfa, CHEN Youfei, CHEN Junming
    2011, 13(2): 157-163. https://doi.org/10.3724/SP.J.1047.2011.00157
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    The Topographic Wetness Index (TWI) is frequently used to simulate the soil moisture conditions in a watershed quantitatively. The index that extracted from DEM is an important factor with explicit physical significance in the rainfall-runoff process models. Some previous studies discovered that the TWI would change with the resolution of DEM from which it was derived and this change, and terrain heterogeneity of DEM grids were employed to explain the scale dependency. In this paper, we explored the resolution effects of TWI and the influence of terrain heterogeneity of DEM grids. The research area is located in Xiyuanxi watershed, Xiamen City of Fujian Province, which includes different terrain types such as hill, platform, plain, etc. A fine-resolution DEM with 2.5m grid size was used to investigate the scale dependency of TWI values when converting DEM with resolution of 20m. Four terrain and heterogeneity attributes were employed as the quantitative indices of terrain heterogeneity of DEM grids, i.e. standard deviation of elevation, relief, landscape fragmentation index and landscape diversity index. The correlation and regression analysis was performed to identify sensitive and correlative responses between each terrain heterogeneity index and TWI variance as resolution was changed. The results indicated significant negative correlations between the terrain heterogeneity indices and the TWI variance (the Pearson correlation coefficients were -0.707, -0.712, -0.779 and -0.841 respectively, all based on a high confidence level of 0.01). By extrapolating the fitted curve for the terrain heterogeneity indices and TWI variance, the logarithmic curves fit the optimal equations well (the coefficient of determination are all greater than 0.9, F>F0.01). So, these indices can be used to evaluate the impact of the terrain heterogeneity on the TWI. Meanwhile, the regression models can improve the accuracy of the TWI derived from a coarse resolution DEM. The effect discussed in this study is helpful in providing a more accurate data for the TWI applications.
  • ARTICLES
    Influence of Land Use Change on Topsoil Organic Carbon Storage of Paddy Fields in Wujiang City
    GAO Jianfeng, PAN Jianjun, LIU Shaogui, JIANG Xiaosan
    2011, 13(2): 164-169. https://doi.org/10.3724/SP.J.1047.2011.00164
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    Soil organic carbon (SOC) storage is an important parameter of soil environmental quality, and agriculture soil is easy to be interfered by human activities and also could be adjusted in a short time scales. The ongoing land-use changes in developed area in China have important influence on SOC (soil organic carbon) sequestration. In this research we take Wujiang County as a case, evaluated the influence of land-use changes on the soil carbon sequestration ability in the paddy fields. The land use classification in Wujiang County from 2000 to 2005 were conducted by a new methodology that integrates 8-day composite images (500-m and 250-m spatial resolution) from the moderate resolution imaging spectro-radiometer (MODIS) sensor with Landsat data. The maximum likelihood classification (MLC) method was used to conduct TM/ETM images classification. The vegetation index (NDVI, EVI) and land surface water index (LSWI) mask method was used to conduct MODIS images classification. The land use class map and the density of soil organic carbon (SOC) data from the 2nd State Soil Survey and the nationwide arable soil monitoring system (NASMC) along with county-level soil reconnaissance data were further used to calculate the soil carbon sequestration ability. The result showed that irrigation-based rice cultivation in the study area has induced significant enrichment of SOC storage in paddy soils. But carbon sequestration ability tended to decline over the most recent six years due to decreasing in paddy area and shifting to other land uses. The paddy soils have switched from carbon sink to carbon source since 2001. The total SOC sequestration in 0-15cm soils in 1984, 2000, 2001, 2002, 2003, 2004 and 2005 were 107×103t,9.2×103t,-8.0×103t, -21.2×103t,-49.2×103t,-41.6×103t and -49.4×103t respectively. The results of this study suggested that land use changes have a great influence on topsoil carbon (C) sequestration, particularly on C stocks and C sequestration potential in paddy fields in developed areas of China.
  • ARTICLES
    Transport Superioriy Degree Analysis and Application for Major Function Regions Zoning at Provincial Level:A Case Study of Hebei Province
    ZHANG Xin, LIU Haiwei, DONG Wen, CHEN Huabin, CHI Tianhe
    2011, 13(2): 170-176,280. https://doi.org/10.3724/SP.J.1047.2011.00170
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    Transport plays an important role in the history of human civilization and social development, which joins geographical spaces and social economic activities. The transport superiority degree is one of the assessment indexes for the major function regions zoning of our country. The study on Chinese major function regions zoning which oriented transport superiority degree analysis method is of great importance for the major function regions zoning of provinces. By using GIS technology and combined with Hebeis local conditions, we used latest administrative division data, based on geographic database and statistical data of 147 counties of Hebei Province to compute the transport superiority degree. First, the transport dominance computation model is established in this paper. Then density, proximity and accessibility of Hebei Province are analyzed quantitatively and qualitatively. We determined the weights of three indexes by using analytic hierarchy process, and they are 0.267, 0.404 and 0.329. At last, the comprehensive evaluation on the transport superiority degree for each county is achieved. By contrast, the regions of the highest transport superiority degree of Hebei Province concentrate in Shijiazhuang, Qinhuangdao, Tangshan, Handan and their nearby towns. Northern mountain area of Hebei, which merely account for 19% of the total area of the province, has a lower transport superiority degree. Thus, the government should make great efforts to improve the transportation condition in northern mountain area of Hebei, so as to narrow the economic development gap to realize the coordinated development within different regions of Hebei. The majority region of Hebei, which is about 59.2% of the total area, have the middle level or a little better in transport superiority degree, and the level of traffic is comparatively well in Hebei. The result maps reveal the regional difference and the distribution pattern of Hebei, and the result of this paper is provided as reference for traffic planning and major function regions zoning. Furthermore, the per-capita GDP and the transport superiority degree of every county was compared and analyzed. The computation result is that the per-capita GDP of 2006 presents a not very strong positive correlation with the transport superiority degree for each county with a correlative coefficient of 0.408.
  • ARTICLES
    Index System and Evaluation Methods of Resources and Environment Carrying Capacity in Principal Function Area Division at Provincial Level
    DONG Wen, ZHANG Xin, CHI Tianhe
    2011, 13(2): 177-183. https://doi.org/10.3724/SP.J.1047.2011.00177
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    Resources and environment carrying capacity, which is one of the main basis for the evaluation of principal function area division, reflects the adaptive relationship between resources and environment, human economic and social activities, and is also one of research and practice focuses in principal function area division. In this paper, we analyzed the meaning of present researches about resources and environment carrying capacity, the related indexes and their evaluation methods, and discussed the practice about resources and environment carrying capacity calculation and evaluation in principal function area division at provincial level. The existing index system and index calculation methods were created on the base of natural properties only, and ignored the impact of human activities on natural resources and environment, and can't fully characterize the actual carrying capacity of resources and environment of the evaluation area. In order to solve these problems mentioned above, we proposed to use air, water, land, energy and ecology as five main natural constraint elements of regional development, and evaluated each element from both resources and environment attributes about its development potential. In addition, we improved the index calculation methods through increasing the contribution of human science and technology component over the existing method, i.e. calculation of total amount of nature. Based on the above ideas, we took principal function area division at provincial level as an example to propose a resources and environment carrying capacity evaluation index system, which contains 5 elements and 16 indexes, on the base of analyzing the existing 5 resources and environment related indexes. Finally, "water environment capacity" index was selected to explain the improved methods of index calculation. This index system and index calculation method can be used in some related filed also.
  • ARTICLES
    Analysis of Field Damage Distribution in Wenchuan Earthquake Based on Fishnet Technology
    ZHANG Jun, ZHOU Chenghu, GUO Zhaocheng, YANG Panxin, SUN Xiaoyu
    2011, 13(2): 184-188. https://doi.org/10.3724/SP.J.1047.2011.00184
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    Based on Fishnet technique, by implementing data estimate, data integration and dynamic management to remote sensing images after Wenchuan Earthquake and to basic geographical information for Longmen Shan region, we got a cluster of remote sensing images which can cover the whole Longmen Shan region. Because the distribution of field damages mainly shows in group and in strap, so, slight field damages, although can not be interpreted accurately from a remote sensing image, their summation occupies a considerable area. Therefore, we divided the damages into six density classes on remote sensing images. With Fishnet technique, we resolved some troublesome problems about pick-up of filed damages from remote sensing images, by means of contrasting and analyzing among the number of different time and different data sources remote sensing images. These troublesome problems mainly were pick-up of filed damages in the deep shallows of highly relief mountain region and pick-up the field damages which takes on same characteristics or color in remote sensing image, etc. We finished the remote sensing image interpretability of field damages by artificial visual interpreting comparison and the verified partly results of interpretability in the field. Ultimately, acquired area of field damages is 972.78km2. The distribution of field damages shows apparently the characteristics in subsection parallel to Longmen Shan faults and in zoning perpendicular to Longmen Shan faults. Subsection parallel to Longmen Shan faults: in southwest zone, field damages take on sheet lumped distribution and impact on wider surface area; in the middle zone, distribution of field damages shows bottle-necked shape and range of influence is minor in surface; in the part of east north, field damages take on scattered distribution. Subsection perpendicular to Longmen Shan faults: 80% of field damages distribute in the middle mountain zone, field damages mainly distribute along Wenchuan-Maowen faults and partly river in latter mountain zone. Disasters mainly scatter in two areas, around Mianzhu and Anxian regions and Jiangyou Municipal District in the anterior mountain.
  • ARTICLES
    Study on the Spatial Structure of Valley Economy Development ——A Case of Mentougou District in Beijing
    LIU Chunla, ZHANG Yifeng, CAO Jun, MU Songlin, JIA Dameng, LAN Tingting
    2011, 13(2): 189-197. https://doi.org/10.3724/SP.J.1047.2011.00189
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    Valley economy is a new mode of mountainous development. By studying its spatial structure, we can interpret the spatial structure, find out spatial characteristics, and probe internal mechanism and development rules, which will make reference for mountain economies' space optimization, population and industrial distribution. This posses significance value theoretically and practically. Mentougou District is the pure mountains area of Beijing, the development of which is rather typical. Adopting DEM data, using ArcGIS, SPSS software, in this paper we comprehensively considered the factors of height, length and slope, and then extracted the representative valleys of Mentougou. On the base of interpreting the content of valley economy spatial structure in Mentougou, we obtained basic characteristics of spatial variation of valley economy by spatial data analysis. Through spatial structure analysis of village based valley economy and evaluation of current situation of valley economy, we discovered that"one core area, several growth areas, a spindle, several local axes and numbers of nodes"represent the typical spatial structure of Mentougou valley economy. The development mode of the typical valley economy has integrated rural spatial structure, gathered rural population, coupled mountain transportation network, eventually promoted economic development in mountainous areas. In all, development of valley economy in Mentougou showed the characteristics of spatial concentration, which played a role in gathering population, resources and industry, and promoted mountain farmers to get rich. In future, valley economy has a trend of centrality so we need make scientific planning, and doing works for the further optimization. The results of this study, initially revealed basic situation of the spatial structure of valley economy development in Mentougou, can provide reference for valley economy planning and its spatial structure optimization. The formation of spatial structure of valley economy development in Mentougou is closely related to the complexity of their own development, the complexity of the system elements and the integrity of the driving mechanism.
  • ARTICLES
    Evaluation and Analysis in the Regional Eco-environmental Vulnerability Based on GIS:Taking Hunyuan County of Shanxi Province as an Example
    XU Mingde, LI Yanchun, HE Juan, NIU Jian, LI Jingni
    2011, 13(2): 198-204. https://doi.org/10.3724/SP.J.1047.2011.00198
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    Based on environmental ecology and restoration ecology, in this research we took regional and sustainable development as the guiding ideology. Then the ecological environmental vulnerability was carried on systematically, and the framework of synthetic analysis and evaluation on ecological environmental vulnerability was confirmed. Considering natural and artificial factors, the systematic evaluation index system was determined, including target layer-criterion layer-index layer. The 30m×30m grid system as a basic analysis unit was established, which broke with the traditional mode of administrative region as a basic analysis unit. Through the GIS grid technology and the multiple attribute characteristics analysis on the fuzzy comprehensive evaluation, the new technology "decomposition-synthesis method" was proposed, which was based on the geographic information system (GIS) and AHP-fuzzy comprehensive evaluation model. The weight for every evaluation index was confirmed with analytic hierarchy process (AHP) method, and the improved "fuzzy vulnerability evaluation model" was established. On the basis of the GIS technology, the classification of vulnerability was carried out, which reflected the spatial distribution of the ecological vulnerability scientifically and quantitatively, so that the result of evaluation made the natural elements with continuity, and was beneficial to the macroscopic realization and problem identification of the ecological environmental vulnerability. Meanwhile, it enriched the theories and methods of the analyses on the ecological environmental vulnerability. The established model and the technical method were used to verify the analysis for Hunyuan County, Shanxi Province. The results agree well with the actual situation of Hunyuan County, which shows that the established model and technical approach is feasible.
  • ARTICLES
    Design and Realization of Calculation and Analysis System for Agricultural Potential Productivity
    CHENG Chuanzhou, YANG Xiaohuan, XU Ruina, SHI Ruixiang, WANG Jing, LI Yuejiao
    2011, 13(2): 205-212. https://doi.org/10.3724/SP.J.1047.2011.00205
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    Food security is a major problem relating to the development of national economy, the stability of social political situation and the solid of state power, and occupies an important position in the national security system. With a large population and a relatively less arable land area, food security has always been a top priority matter of concern for China, while the productivity of grain is the key for food security. With the increasing population and rapid economic development, food security have become increasingly prominent, so it is important to study agricultural potential productivity, because it can describe the food production capacity in a region. It is of great practical significance to exploit agricultural resources rationally and then guide the agricultural production. In this study, supported by GIS technology, COM component technology and plug-in technology, using C # as the development language, ArcEngine as the development components, SQL Server as the database software, and ArcSDE as spatial database engine, Visual Studio. NET as the development platform, we designed and implemented an agricultural potential productivity calculation and analysis system, which included the functions of database management, meteorological interpolation, calculation and analysis of agricultural potential productivity, expansion of agricultural potential productivity model, graphics output and system management. Then we built an agricultural potential productivity database with unified coordinate system, unified data format, unified spatial scale and the ability of dynamical update. In addition, we took Shandong Province as the study area, calculated the agricultural potential productivity of the province and analyzed the rationality of the calculation model. System application results showed that, the system can be well applied in the study of agricultural potential productivity calculation and analysis, for it can provide basic data and software support for agricultural potential productivity calculation and analysis.
  • ARTICLES
    Construction and Application about the Monitoring System of Water Vapor Derived from Ground-based GPS in Chengdu
    WANG Hao, LI Guoping
    2011, 13(2): 213-218. https://doi.org/10.3724/SP.J.1047.2011.00213
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    Water vapor plays a very important role in weather and climate changes. Though water vapor is very little in the atmosphere, but its change, in the atmosphere, is very obvious. Water vapor is also an important kind of greenhouse gas in the atmosphere whose spatial distribution is extremely uneven and time variation is very fast. It is not only the main driving force of weather and climate changes, but also an important formation and evolution reason for disastrous weather, especially medium or small scale disastrous weather. In satellite geodesy, GPS positioning accuracy was primarily affected by water vapor. Therefore, people learn from the elimination of noise in the measurement process, gradually to develop out of a new discipline—GPS meteorology (GPS/MET). Along with the development of GPS meteorology, people start to utilize ground-based GPS technology in order to effectively compensate for the defects of traditional detection technologies spatially and temporally and obtain water vapor information with high-precision, high-capacity and high space-time resolution ratio through ground-based GPS water vapor monitoring network. How to measure water vapor content in the atmosphere, to monitor the distribution of water vapor and its trends, which have an important practical significance to meteorological department, especially in monitoring and forecasting disastrous weather on a medium or small scale. The main content of this paper is to launch the development of ground-based GPS water vapor monitoring system; the purpose is to make this system fill in the blank of the application of GPS inversion water vapor technology in Sichuan and even the southwest areas of China, and also enhance the capacities of meteorological department on forecasting and monitoring of medium or small scale disastrous weather, as well as promote the work of many related meteorological operations.
  • ARTICLES
    Research on Web Services-based Geospatial Information Application Integration Solution
    WU Qunyong, WANG Qinmin
    2011, 13(2): 219-225. https://doi.org/10.3724/SP.J.1047.2011.00219
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    Based on the analysis of application integration and its development, using web service technology, a service-oriented framework for geospatial information application integration is proposed and established, which includes web application layer, service integration layer, service layer and UDDI and so on. The web application layer contains the web service client and request broker. The functions of the client are to implement the request and ask of the customers. The client affords personalized user interfaces for different customers and affords application services for different business. The request broker is the interface for the client accessing the services. The services integration layer is a wide range of services integrated approach to achieve service-oriented application integration, including service chaining, service composition and workflow (XLANG, BEPL4WS). The services layer provides meta-services for the application integration framework, and provides geospatial data web services methods and legacy system web services package methods. UDDI provides a distributed registry to achieve a "one-registration, released around the world share" function. The aim of the service-oriented geospatial information application integration framework is to achieve the service release, dynamic discovery and dynamic composition in order to achieve the geospatial information services integration and the applications integration. In this framework, it is the key points to integrate the geospatial information and the legacy system and to construct the geospatial information services chaining and services composition. The integration solution for the legacy systems is put forward from the data level and the business level. In the data level, the geospatial data package strategy based on XML&GML and based on Web services interface are established. In the business level, the web services package strategy is established according to the system functions and the business logic. The detail degree that the system function decomposes decides directly the web services function and web services composition. The integration solution for chaining web service and service composition for geospatial information are also addressed including series model, parallel model and hybrid model. These three services chain models are designed to achieve the services chaining and the services composition to complete geospatial information integration and application integration.
  • ARTICLES
    Accuracy Analysis of the 1∶100 000 Topographic Maps of Henan Province in Early Period of the Republic of China
    KONG Yunfeng
    2011, 13(2): 226-233. https://doi.org/10.3724/SP.J.1047.2011.00226
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    Surveying and mapping were active in the period of later Qing Dynasty and early Republic of China, and numerous topographic maps (scale: 1∶25 000 to 1∶200 000) covering major areas of China were published. For efficient utilization of the old maps, this paper aims to evaluate the accuracy of the 1∶100 000 topographic maps of Henan Province in early period of the Republic of China (1915~1916). The possible sources of map displacement were also discussed using longitude and latitude records in historical books. The map accuracy was analyzed using the displacement of sampling points. The 159 sheets of old maps were overlaid with current map layers in ArcGIS for comparison. Using ArcGIS Spatial Adjustment Extension and searching the same point in old maps and new maps, 741 displacement links with original and actual coordinates were determined. The displacement map and statistics show that: (1) the longitude and latitude errors of old maps are distributed unevenly, and the average shifts are 6.28 minutes toward west and 2.23 minutes to the south, with standard deviation of 3.76 and 2.51 respectively. (2) Both the absolute and relative errors at longitude direction are higher than that at latitude direction. At the same time, the errors present an autocorrelation pattern and the Moran’s I of longitude and latitude errors are 0.85 (Z=57) and 0.69 (Z=46). (3) In general, the maps in plain area are better than those in mountain area in term of relative accuracy. (4) The errors in old maps present three patterns: higher absolute and relative accuracy, lower absolute but higher relative accuracy, and lower absolute and relative accuracy. To explore the source of absolute errors, the longitude and latitude records of the prefecture cities and county towns were collected from records in historical books. Mapping the historical records as point layers and overlaying it with old and current residential map layers in ArcGIS, the point displacements show that the shift trend of old maps is similar to those coordinate records in Draft History of Qing. Regression analysis confirms the linear and positive association between them. A hypothesis formulated from this finding is that the longitude and latitude records in later Qing Dynasty were utilized in early period of the Republic of China. It is also suggested that during the map investigation, both the newly-surveyed maps and existing older maps were also used in some areas.
  • ARTICLES
    Assessment of Ecosystem Health in Lashihai Lake Using AHP Method
    MA Liguang, CAO Yanrong, LI Xintong
    2011, 13(2): 234-239. https://doi.org/10.3724/SP.J.1047.2011.00234
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    The objective of this research is to analysis wetland ecosystem health status of the core region of Lashihai Lake in Yunnan Province. Indictors that have impacts on ecosystem health were considered using the Analytic Hierarchy Process (AHP) methods. The integrated spatial analysis model was constructed to meet the requirements such as scientific research, systematicness and feasibility as well as data availability. Firstly, the indicators and indicator system were established based on the current status and characteristics of Lashihai Lake ecosystem, combined with series of items such as ecosystem functions monitor and indices under the principle of systematicness, scientificalness and feasibility. Secondly, using the AHP method, an integrated spatial analysis model for Lashihai ecosystem health study was constructed comprehensively and the 6-level assessment criterion has been established. Finally, the data-driven model run with existing data context and the weight of each indicators were calculated, and the spatial distribution of Lashihai Lake ecosystem health status were demonstrated by mapping.The research results show that ecosystem health in Lashihai Lake wetland is good, by there is no very stable and extreme stable region. The stable region is about 61% of the whole areas, and 39% of the areas is vulnerable area that should be paid more attention in future development. Especially, the eco-tourism developing activities across the lakeside region should be given scientific planning and proper management. The indicators and indicator system selected in this paper fit the true circumstances of Lashihai Lake region. The results can guide future planning in this region for both ecosystem management and economic development.
  • ARTICLES
    Analysis of Minimum Error at River Source to Extract River Network Based on DEM
    CHEN Dongping, CHEN Ying, CHEN Xingwei
    2011, 13(2): 240-244. https://doi.org/10.3724/SP.J.1047.2011.00240
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    With the development of hydrological model, extraction of river drainage network has been a hot topic in hydrology research. River drainage network was extracted based on topographic maps or drainage maps by digitization in the early years, but the result was influenced by data source resolution. There are presently two kinds of methods to extract river drainage network based on DEM. One is to overlay the extracted river drainage network based on DEM on the river digitalized maps which came from drainage maps or vector layer of river, to make the extract drainage network more similar to the actual river networks. But the accuracy of river drainage network depends on the resolution of drainage maps or vector layer of river. The other one is based on "inflection point" to extract river drainage network, however, the assumption of "inflection point" exists the problem of choice of scale-free interval. To solve the above problems, the river source minimum error (RSME) method was presented based on DEM in this paper. First, the relationship between the distance error of the actual river source and the extracted river network source and the size of grid was established; second, the minimum distance error was adopted as the principle to solve the problem of the uniqueness in watershed drainage network extraction, and then the river network was determined. Taking Jinjiang River as an example and using DEM with 30m resolution as data source, the RSME method was adopted to extract Jinjiang River drainage network on the platform of ArcGIS9.2. The result showed that the distance error between the river source and the extracted river network source is the smallest one when the grid numbers are up to 5814 and the minimum river length is 42m, the corresponding fractal dimension is 1.389. Moreover, the result indicated that the proposed RSME method is reasonable to extract watershed drainage network.
  • ARTICLES
    A Plug-in System for Taihu Lake Water Pollution Diffusion Simulation
    HAN Yu, GUO Fei, GE Cheng, ZHANG Feng
    2011, 13(2): 245-251. https://doi.org/10.3724/SP.J.1047.2011.00245
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    In recent years, water pollution incidents occurred frequently in China, which has caused widespread concern in society. A number of water pollution diffusion simulation systems are developed in order to grasp the actual situation of water pollution, and then execute a more scientific management for the water environment. However, this kind of systems developed with the component technology is so complex that most of them have poor software scalability and is difficult to maintain after delivery. In order to ensure system scalability, it needs a kind of loose coupling mechanism to combine water pollution diffusion model, GIS and visualization modules in one system. Plug-in technology can reduce the coupling between system modules. Software developed with plug-in technology can extend its functionalities without modifying its main program. In this paper, the general structure of plug-in software is described in the first place, and then the designs of the host program and plug-ins are showed, which are used to drive the development of the plug-in Taihu Lake water pollution diffusion simulation system. This is a valuable attempt to develop customizable GIS with plug-in technology. At last, the plug-in Taihu Lake water pollution diffusion simulation system is verified to achieve three-dimensional visualization of pollutant concentration and flow of Taihu Lake by examples. The plug-in Taihu Lake water pollution diffusion simulation system developed with plug-in technology (a kind of loose coupling mechanism) that integrates water pollution diffusion model, GIS and visualization modules not only simulates intuitively spatial distribution of water pollution and dynamic evolution process of water pollution diffusion in order to provide effectively decision support for water pollution control in Taihu Lake, but also has excellent dynamic scalability that extends system functionality by adding new plug-in without affecting the system that has been deployed.
  • ARTICLES
    Image Recognition and Extraction of Poplar Plantation Based on MLC and LSU:Case of Wen-an County of Hebei Province
    ZHAO Yuluan, LI Xiubin, XIN Liangjie, ZHANG Ying
    2011, 13(2): 252-259. https://doi.org/10.3724/SP.J.1047.2011.00252
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    China is actively implementing the fast-growing and high-yielding timber base construction program in the past few years. There is an increasing number of poplar woodland in the North China Plain over the past decade, and the North China Plain is one of the major grain-producing areas in China. So the expansion of poplar woodland may influence food security, which attracts more and more attention. The area of poplar woodland is a key to the attention. We used TM band 1, band 2, band 3, band 4, band 5, and band 7 of Landsat 5 as fundamental datum and preprocessed them, then produced a new data set of 13 bands by generating vegetation index and principal component analysis. At last, we chose band combination of visual interpretation by using optimum index factor (OIF) and extracted information of area of poplar woodland by using maximum likelihood classification (MLC) and linear spectral unmixing (LSU). The results showed that: (1) Visible red light, near-infrared, mid-infrared, canopy vegetation index, and the first three principal components were dominant to the information extraction. (2) The 13 bands were separated according to correlation coefficient of the bands and then OIF was computed, which can save work time. (3) The area of extracted pixels of poplar woodland by MLC was 11 259.84ha, which accounted for 10.95% of the research area. Through outdoor authentication, the precision of producer and user was 84.07% and 93.14%, respectively, the outcome of classification and mapping was good. (4) LSU is a sub-pixel technology. So the area of extracted pixels of poplar woodland by LSU was better than that by MLC in the area of surface fragmentation. The extracted area by LSU reached 11 259.84ha, which increased largely in the research area. And it accounted for 13.33% of the research area. In a word, the two ways complemented each other, which can supply a sample for the quickly investigation of poplar woodland and the research on land-use conflict between woodland and arable land.
  • ARTICLES
    Application of 3G and 3S Integration Technology in Land-use Law Enforcement Inspection
    DONG Tingxu, WANG Jianhua, CHEN Chaozhen ZHANG Xinhe
    2011, 13(2): 260-265. https://doi.org/10.3724/SP.J.1047.2011.00260
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    The law enforcement inspection of land satellite image is an important means for the government to implement the strict land management. Taking the 2009 law-enforcement inspection of land satellite image in Mianyang City as an example, we selected the 02B CBERS remote sensing image of 2009 and 2010 as an information source to study the application methods of the 3G and 3S technology in law-enforcement inspection of land satellite image. We obtained land-use change information using RS, gathered spatial and attribute information of land-use change plots by VRS-GPS, transmitted the site data by 3G communications technology, and used GIS technology for data processing, spatial analysis and visualization management output. The results showed that: it is feasible to gain the land use change information, identify the monitoring spot, survey the spots, transmit wirelessly the data, compile the maps and construct the database based on 3G and 3S integration technology. It has the characteristics of real time observation, accurate positioning, wireless transmission, rapid analysis, visualization output and it has good application prospect. It can provide timely the land-use change monitoring and accurate measurement information, and provide scientific services for decision-making to deal with the illegal land-use.
  • ARTICLES
    A Method of MODIS Sea Ice Edge Extraction Based on Agglomerative Hierarchical Clustering Method
    WANG Ning, ZHANG Xi, JI Yonggang, LU Tongzhen, YU Bo
    2011, 13(2): 266-272. https://doi.org/10.3724/SP.J.1047.2011.00266
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    In this paper we suggested the importance of sea ice edge in our country's sea ice monitoring and forcasting. The sea ice edge is the boundary between water and ice. Monitoring of sea ice edge's position and the change is vital to sea water exchange, marine fishery, nearshore marine operation, offshore oil-gas exploration, meteorological observation and so on. The conventional method of sea ice edge extraction often has the shortcomings of massive mixed spots existing and the slow computation speed. Clustering is a way to group objects into more than one cluster, so that the same cluster objects have a higher similarity, and an object in a different cluster is larger. Agglomerative hierarchical clustering algorithm is a bottom-up policy. It first considers each object as a cluster, and then combines these clusters into larger cluster, until all the objects in a cluster, or one condition is met. Based on the agglomerative hierarchical clustering algorithm, combined with MODIS images and the characteristics of Bohai suspended sediment distribution, we discussed the MODIS image segmentation algorithm. The algorithm regards spectral characteristics and shape properties as the rule, joining image meshing, breaking grouper and noise removal and other functions, and optimizing the ice-water identification parameters. This algorithm can effectively improve the availability and accuracy of image segmentation results. We combined this algorithm and edge detection algorithms to extract sea ice edge of the image segmentation results. The algorithm has a better removal of broken spot and noise. Comparing the result of interpretation of MODIS data and the result from the algorithm, we can conclude that the algorithm can better complete the MODIS image segmentation and on this basis we can have a better result of the sea ice edge.
  • ARTICLES
    Extraction of Paddy Land Area Based on NDVI Time-series Data: Taking Jiangsu Province as an Example
    MIAO Cuicui, JIANG Nan, PENG Shikui, LV Heng, LI Yang, ZHANG Yu, WANG Ni, LI Jun
    2011, 13(2): 273-280. https://doi.org/10.3724/SP.J.1047.2011.00273
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    As a kind of crucial data which was able to reflect the continuous coverage of vegetation on the earth surface, the long time-series MODIS NDVI products have already become a reliable data source used in remote sensing for crop measurement. In this paper, a long time-series and high-resolution (250m) MODIS data in 2008 was used to extract the area of the paddy land in Jiangsu Province, China. In the beginning, an annual time-series NDVI dataset of the study area was built up by pre-processing,and a reconstruction of time-series based on Savitzky-Golay filter provided this study excellent images with the better visual effect and NDVI temporal profile. Considering the paddy phenological calendar, the identifiers of paddy were parameterized as starting time, range, extent, and maximum of NDVI during the growth period. In the end, through comparing the phenological key values, a reasonable classification rule was generated based on the thresholds of phenological key values, and a decision tree classifier was constructed to extract Paddy land area, whose precision was 87.5%. It turned out the feasibilities of long time-series MODIS NDVI data and our classification strategy adapted to the extraction of crop land area.
  • ARTICLES
    Landscape Diversity Assessment in Longxi-Hongkou Nature Reserve Before and After the Wenchuan Earthquake Based on Remote Sensing
    LIU Xiaolan, WANG Wenjie, LI Tiantian, ZHAO Xingzheng, MA Hongwang
    2011, 13(2): 281-288. https://doi.org/10.3724/SP.J.1047.2011.00281
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    Landscape diversity is the result of natural disturbance, human activity and the internal succession of vegetation. It also is a major level of biodiversity. In this paper, the authors established a landscape classification system for Longxi-Hongkou Nature Reserve, Sichuan Province, with vegetation types and land-use being the main classify basis, interpreted two different phases of Landsat TM images before and after the Wenchuan Earthquake of the reserve, developed the landscape spatial pattern of the study area, and analyzed the characteristics of landscape changes before and after the earthquake. The results showed that: 1) After the earthquake, the total number of patches (NP) in the study area increased by 2.36 times, so landscape became more fragmentation; after the earthquake, forest landscape (broad-leaf and coniferous) went into smaller pieces, implying the weakness of its dominant position. Broad-leaf, meadow and rare landscape turned into the new dominant landscape. 2) The SHDI and PAFRAC of the study area increased 11% and 7% respectively. It implied the diversity and heterogeneous of the study area strengthened, and landscape structure was more complex. The Dominance and CONTAG both decreased 30%. It explained that the number of large patches decreased, the landscape contagion of the study area fell and its connection declined. 3) The habitats fragmented, the ability of maintain biodiversity was cut down. Vegetation cover dropped, and edge habitats grew in number, leading to a weaker ability of maintain water, a raising risk of soil erosion, landscape structure destroyed and the protective screen function slipped. Therefore, Wenchuan Earthquake and its secondary disasters as natural disturbance factors have changed the landscape structure and landscape pattern of the study area, undermined the suitable habitats of rare animals and plants, posed a threat to endangered species and natural ecosystems, all those would change the biodiversity and ecology environment of the region.