Table of Content

    20 September 2010, Volume 29 Issue 9 Previous Issue    Next Issue
    Celebration of the70thanniversary of IGSNRR,CAS
    Retrospect and prospect of regionalization system of China
    WU Shao-hong, YIN Yun-he, FAN Jie, ZHENG Du, YANG Qin-ye
    2010, 29 (9):  1538-1545.  doi: 10.11821/yj2010090001
    Abstract ( )   PDF (247KB) ( )   Save

    Regionalization system of China has attained substantial achievements in the last decades by the Institute of Geographic Sciences and Natural Resources Research under the Chinese Academy of Sciences. Based on the stages of "integrated physical geographical regionalization-eco-geographical regionalization-comprehensive regionalization",significant progresses and achievements of some important regionalization schemes were introduced in this paper. In 1950s, integrated physical geographical regionalization was initiated in order to guide the distribution of agricultural production. In the 1990s, eco-geographical regionalization was carried out to instruct ecological development and environmental protection based on ecological theories and methods. Since the end of the 20th century, comprehensive regionalization has been developed along with the further research into earth science and sustainable development. A combination of physical factors with socio-economic factors has been the distinguishing characteristic of recent regionalization research. Moreover, the continuous innovation in methodology and technology, such as remote sensing, geographical information system and numerical simulation, has promoted the development of regionalization research. Regionalization system which was tightly coupled with national economic development and environmental protection would be an important direction of physical geography and even geography in future development.

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    Retrospect and prospect of geomorphology in IGSNRR, CAS
    SHI Chang-xing, XU Jiong-xin, CAI Qiang-guo, JING Ke, LI Bing-yuan, FANG Jin-fu, QI De-li, WANG Sui-ji, YAN Yun-xia
    2010, 29 (9):  1546-1560.  doi: 10.11821/yj2010090002
    Abstract ( )   PDF (180KB) ( )   Save

    Geomorphology has been a main subject of the modern geography, and it has been regarded as one of the mainstay subjects in the Institute of Geography (now, the Institute of Geographic Sciences and Natural Resources Research), CAS. The studies done by the geomorphologists in the institute have made a great contribution to national economic construction as well as to the knowledge of geomorphology. This article makes a general review on the main progress in geomorphology made by the geomorphologists in the institute since the institute was founded, including the progress in the fields of fluvial geomorphology, Loess Plateau and slope geomorphology, Tibet and Antarctic landforms and Quaternary, karst and tourism geomorphology, experiments and simulations of landform processes, and cartography of landforms. The existing Department of Geomorphology and Watershed Processes in the institute focuses on studies of slope processes and slope reclamation, sediment erosion and control in watersheds, sediment transport and river channel changes, land-ocean interactions in estuaries, Simulation of dynamic landform systems, karst landform and hydrochemical processes, regional and applied geomorphology. Some suggestions are proposed for improving the roles of the department in developing the geomorphologic sciences and serving the national economic construction.

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    An overview of research on climate change in China during the past 2000 years
    ZHENG Jing-yun, SHAO Xue-mei, HAO Zhi-xin, GE Quan-sheng
    2010, 29 (9):  1561-1570.  doi: 10.11821/yj2010090003
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    In this paper we summarize the major progress made by the scientists at the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences on the study of climate change in China during the past 2000 years and provide insight to future research activities. Faced with hot scientific issue in the field from international projects, much research has been performed at the Institute in the past decade, and many new and significant results are produced in the areas of collection and compilation of various proxy data, construction of an extensive database of climate change in China, reconstruction of temperature and precipitation series, and analyses of the spatial and temporal characteristics of climate change for the past 2000 years. In the future, in addition to reconstructions of climate change based on high-resolution proxies, such as historical documents and tree-ring data, we need to increase the density and spatial coverage of the proxy data. Using the approach of historical climate modeling, the forcing mechanisms of climate change can be examined. With the advantage of the accumulated research results at the Institute, we can also investigate the interactions between climate change and human society during historical periods.

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    Overview on the research works in the field of environmental geography and human health
    YANG Lin-sheng, WANG Wu-yi, TAN Jian-an, LIANG Tao, DONG Yun-she
    2010, 29 (9):  1571-1583.  doi: 10.11821/yj2010090004
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    In the 1960s, the Institute of Geography called for chemical process research in physical geography and set up the first department on chemical geography in China. The department has participated in all earlier national programmes on environment, which has promoted the development of environmental sciences and technologies in China. The department also has led other institutes in the Chinese Academy of Sciences to conduct the studies on the geographic pathogeny and controlling of Keshan disease, Kaschin-Beck disease and other endemics, which has enhanced the initiation and development of medical geography in China. In 2000, the institute redistributed the department from chemical geography to environmental geography, as well as from medical geography to health geography. The expanding research works include the ecological and health risk assessment of pollutants such as heavy metals, the health risks of global environmental change, the biogeochemical cycles of carbon, nitrogen and their relationships with greenhouse gas emissions. Sets of technologies on site pollution treatment and health protection have been developed. Further research into environmental geography and human health will focus on the chemical property of geographic environment, so as to probe into the interactions among environment, human health and socio-economic development, for human safety and sustainable development.

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    Earth Surface Processes
    The safe use of land resource to avoid flood risk within the lower Yellow River in Kaifeng
    QIN Ming-zhou, ZHANG Peng-yan, ZHAO Zi-sheng, YANG Zhong-hua, ZHANG Xin, HUANGFU Chao-shen, LI Zhi-ping, CHEN Long, HAN Zhi-heng, HUA Gao-feng
    2010, 29 (9):  1584-1593.  doi: 10.11821/yj2010090005
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    The Yellow River channel boundary and beach land use within Kaifeng City were mapped in detail by using 2007 SPOT 2.5 imagery, field surveys, and ArcGIS and ERDAS software. The river channel flood fringe lines of a typical 7-year period between 1992 and 2007 (less than 8000 m3/s) were generated from Landsat TM images of annual largest flood peak between 1992 and 2007, in conjunction with hydrological data along the Yellow River. Additionally, the submerged Yellow River beach areas with certain regular flood flows within Kaifeng City were created overlaid with background data. Certain levels of large floods and their potential submerged areas were calculated within the Yellow River beach in Kaifeng (especially over 8000 m3/s) based on the mathematical model of the 'downstream runoff and sediment of Yellow River' together with data obtained from a large cross section of the river channel after 2004. According to land resource management and safety requirements for flood transit within the channel, the current issues regarding the lower Yellow River are discussed, including the increased threat of floods in low beach villages, the infrastructure of agricultural development, the living condition of farmers within this Yellow River beach area, and the negative effects of brick-tile kilns and borrow pits on farmland and farming activities. Four principles of safe land use to avoid flood risk are proposed as follows: 1) protecting and using land resources to improve ecological and economic efficiencies as a whole; 2) utilizing land resources based on suitability; 3) prioritizing 'easily exploitable beach land', such as high and flat beach; 4) exploiting land resources intensively while decreasing beach land utilization rationally. Finally, four zones of safe land use to avoid flood are suggested in Kaifeng beach: a) the risk buffer zone close to the river channel (less than 4000 m3/s, about 200 m from the river course waterfront); b) the zone suitable for cultivated land near the river channel (4000-6000 m3/s); c) the zone of relatively stable land use (6000-8000 m3/s); and d) the zone of stable land use (above 8000 m3/s). At the same time, important measures of safe use beach land resources to avoid flood risk are proposed.

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    Susceptibility assessment of secondary landslides triggered by earthquakes: A case study of northern Wenchuan
    TAO Shu, HU De-yong, ZHAO Wen-ji, FAN Yi-da, WANG Zhi-heng
    2010, 29 (9):  1594-1605.  doi: 10.11821/yj2010090006
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    The Ms 8.0 Wenchuan earthquake, which occurred on 12 May 2008 in Sichuan Province, collapsed a great many houses and injured thousands of people. Undoubtedly, it can be predicted that secondary earthquake landslides, as a common secondary hazard triggered by earthquakes, will draw much attention during a long time after earthquake due to the severe geological hazard. In order to remove threat from the secondary disasters effectively, this study used remote sensing and GIS to generate susceptibility maps, taking the case of northern Wenchuan County. Seven factors affecting landslide occurrence have been taken into account in the susceptibility assessment, including elevation, slope, aspect, lithology, seismic intensity, distance to faults and rivers. According to the probability that predicts the possibility of landslide occurrence by information value method and logistic regression separately, the study area was ultimately categorized into five classes, namely, "extremely low", "low", "moderate", "high" and "very high". The result has proved to reflect closely the spatial distributions of landslides in the study area. Subsequently, these two probabilistic and statistical approaches for estimating the susceptible areas of the study area of Wenchuan County were tested. It can be concluded that the predictive capability of logistic regression model appears to be more accurate compared to information value method. It is mainly due to the fact that logistic regression could reduce effectively the subjectivity in selection of evaluation factors and weight assignment.

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    Recent geomorphological evolution of downstream channel and delta of Luanhe River
    LI Gang, YIN Yong
    2010, 29 (9):  1606-1615.  doi: 10.11821/yj2010090007
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    Big dams built across Luanhe River since the 1980s caused great decrease of freshwater and sediment discharges. After Taolinkou Reservoir was built in 1998, the average freshwater decreased to 596×106 m3/a, and the sediment discharges reduced to 24.3×103 t/a. The period of zero flow has prolonged in recent years. Based on remote sensing images from 1979 to 2007, the hydrological changes of the Luanhe River have greatly influenced the development of downstream channel and delta. In a few years after the construction of Panjiakou and Daheiting reservoirs, the downstream channel was cut deeply and eroded widely. But since the 1990s, huge water transfer and irrigation water from the Luanhe River has made the flow in the lower Luanhe River decrease greatly. According to the remote sensing images of 1991, 2000 and 2004, the width of the lower channel became obviously narrower due to the reduction of the river flow. The main channel was 3 to 5 km wide around Macheng in 1979, while the width decreased to less than 100 m in 2004. Although the curving cut-off took place in 1991-2000, the migration of the channel has been limited within the old channel. After 2000, the zero flow happened frequently and the curving cut-off almost ceased. Most point bars inside the Luanhe artificial levee have been reclaimed for farmlands and woodlands. In recent years, the frequent zero flow has deteriorated the river water quality. Based on the remote sensing images of 1979, 1991, 2000 and 2007, the main branch of the Luanhe Estuary in 1979 was abandoned in 1984 and changed its path to Xiaotaiwan. The new main branch kept the single path from then on. Because of the great decrease of the peak flood flow, the width of the estuarine branch became narrower from 1979 to 2007 and the width has decreased to less than 100 m recently. Since the Daheiting and Panjiakou reservoirs were built in 1984, the Luanhe Delta front has stopped growing because most sediment was trapped by the dams. Two segments of the Luanhe Delta were eroded severely. One segment was located around Puochuanmen and the average erosion rate of the sand spit was 29 m/a in recent 28 years. The other was the south flank of the Luanhe Delta, and the average recession rate was 30 m/a in 1979-1991, 24 m/a in 1991-2000, and 27 m/a in 2000-2007, respectively. The severity of recent deltaic erosion was related to the history of the abandoned river branches.

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    Environment and Ecology
    Review on the methods for soil carbon sequestration at regional scale
    CHANG Rui-ying, LIU Guo-hua, FU Bo-jie
    2010, 29 (9):  1616-1628.  doi: 10.11821/yj2010090008
    Abstract ( )   PDF (169KB) ( )   Save

    The study on soil carbon sequestration at regional scale is of great significance, as the Kyoto Protocol and other accords of the United Nations Framework Convention on Climate Change have prescribed that carbon (C) sequestration in soil can be included in the measures to meet the Quantified Emission Limitation or Reduction Commitments in the first period (2008~2012). The methods on estimating the amount of C sequestration in soil at regional scale were reviewed, and the development of the methods was prospected. According to the estimation accuracy and principle, the approaches could be categorized into four methods: (1) Simple model, which scaled up the estimation of SOC sequestration from local plots to region simply or by statistical model, was used widely but with low accuracy. The method was recommended in the region without sufficient data. (2) Inventory method, which was used in soil database of different periods to estimate the change of soil carbon between the two periods, could be used to estimate the amount of carbon sequestered in soil in the past with higher precision, but it could not be used to predict the change of soil carbon in the future. (3) Empirical model including the Book-keeping Model and the Tier 1 and Tier 2 recommended in IPCC Report (2006 IPCC Guidelines for National Greenhouse Gas Inventories) could provide environmental interpretation in soil carbon sequestration with no mechanism explanation. (4) Mechanism model developed from soil organic matter mechanism model (e.g. CENTURY model) based on geographic information system (GIS) could estimate SOC sequestration with highest accuracy among these four methods, which could also provide mechanism explanation in the process of the change in SOC. In summary, each type of the four methods had its own limitation and applicability, so the methods should be chosen based on the site-specific conditions and the research purposes. Finally, based on the analysis of some gaps in the mechanism of soil carbon sequestration, scaling, scenario analysis and soil organic matter model, we proposed that the integrated model,based on GIS, coupling SOM mechanism model, land-use model, econometrical model and regional scale eco-hydrological model, would be developed for studying soil carbon sequestration at regional scale in the future.

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    Division of the geo-ecological boundary in Qinling Mountain Range based on the composition and geographical elements of its Pteridophyta flora
    WANG Jing-lan, LIU Quan-ru, MENG Shi-yong, ZHAO Ming-fei, KANG Mu-yi
    2010, 29 (9):  1629-1638.  doi: 10.11821/yj2010090009
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    The Qinling Mountain Range is considered as an important geo-ecological boundary between the warm temperate and the subtropical zones in eastern China, however, the specific line of the boundary has been controversial among the academic circles. Several studies based on vegetation ecology and flora geography have been done on discussing the division of this boundary, but in all of which Pteridophyta is not included. Pteridophyta is a transitional link between different flora groups in plant evolution, and thus is more sensitive to the environment that fosters it than other plant groups. It is conducive to and necessary for a better understanding of the division of the geo-ecological boundary in Qinling Mountain Range to research into the Range's Pteridophyta flora. In this paper, the composition and geographical elements of the flora of Pteridophyta were studied, and the division of the vertical Pteridophyta spectrum and the further division of the geo-ecological boundary in Qinling Mountain Range were also discussed, by applying the principles of classical florology and using quantitative ecology method as TWINSPAN and DCA into the analyses, based on comparison between the field investigation data and the relevant literatures. The results of our research have shown and revealed: 1) There are 311 species of Pteridophyta, belonging to 85 genera and 36 families in the Qinling Mountain Range; in which the dominant families are Dryopteridaceae, Athyriaceae, and Polypodiaceae, and the dominant genera Dryopteris and Polystichum; meanwhile, the main areal-types of family and genera are tropical elements, while the areal-types of species is dominated by the temperate elements. 2) The altitude of 1000 m a.s.l. at the southern piedmont of the Range should be an important ecological boundary, since the floristic composition of the Pteridophyta below this elevation showed more similar features to the subtropics, while above it the features of the composition and the vertical vegetation spectrum of the Pteridophyta are much closer to the temperate zones. 3) DCA ordination of FER (floristic element ratio) among 15 regions in northern and southern China and the both sides of Qinling Mountain Range strongly supported the hypothesis mentioned above. Based on these results, we tend to deem that the geo-ecological boundary between the subtropical and warm temperate zones lies around the altitude of 1000 m a.s.l. at the southern piedmont of the Range.

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    Carbon emission and carbon footprint of different land use types based on energy consumption of Jiangsu Province
    ZHAO Rong-qin, HUANG Xian-jin
    2010, 29 (9):  1639-1649.  doi: 10.11821/yj2010090010
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    The impact of anthropogenic activities on carbon cycle is fulfilled through land use change. It is helpful to study the impacts of land use change on carbon cycle through linking carbon emissions to different land use types. By using data of energy consumption and land use of Jiangsu province from 2003 to 2007, this paper estimated carbon emission by energy consumption through carbon emission model, and analyzed the carbon emission and carbon footprint of different land use types through linking carbon emission to different land use types. The conclusions can be drawn as follows.(1) Total carbon emission from energy consumption of Jiangsu province increased from 8792.24×104 t (2003) to 16329.85×104 t (2007) with an annual rate of 86%, of which carbon emission from terminal fossil energy use accounted for 53.6%. Because carbon emission from fossil energy use was the main reason for the increase of total carbon emission, developing clean energy and improving energy efficiency are the key methods to decreasing total carbon emission. (2) Per unit area carbon emission of Jiangsu increased from 8.24 t/hm2 (2003) to 15.53 t/hm2 (2007) with an annual rate of 88.5%, of which per unit area carbon emission from residential and industrial areas was the highest (95.62 t/hm2), indicating that dwelling districts and industrial parks were the regions that contributed carbon emission mostly. So, improving energy structure and improving energy efficiency of the above regions was crucial in carbon emission reduction. (3) Carbon footprint of energy consumption was greater than the area of ecological productive land, and the ecological deficit was 1351.28×104 hm2 in Jiangsu in 2007. It is indicated that the carbon absorption of terrestrial ecosystems of Jiangsu Province cannot compensate the carbon emission of energy use. So strengthening environmental protection and enhancing carbon sequestration rate could effectively decrease the carbon emission intensity. (4) The descending order of carbon footprint of different land use types was: residential and industrial area, transportation area, unused land and special use area, agricultural land and water conservancy area. So, adjusting the land use pattern and introducing carbon footprint and carbon emission reduction into land use planning is one of the effective methods to reduce regional carbon footprint. (5) Per unit area carbon footprint of Jiangsu increased from 0.938 hm2/hm2 (2003) to 1.769 hm2/hm2 (2007), which indicates that the carbon footprint of land use had been expanded since 2003.

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    Economy and Regional Development
    Carbon dioxide emission embodied in the international trade flows of iron and steel commodities of China: From the perspective of intra-industry trade
    ZHANG Xiao-ping, WANG Zhao-hong, SUN Lei
    2010, 29 (9):  1650-1658.  doi: 10.11821/yj2010090011
    Abstract ( )   PDF (322KB) ( )   Save

    Due to the existence of international commodity trade flows and economic activity globalization, responsibility for carbon emission reduction at a national territorial level would easily result in carbon leakage, thus may lead to significant misunderstanding in evaluating reduction performance. Accordingly, trans-boundary displacement of emissions resulted from inter-country flows of goods through international trade should be taken into account in the international negotiation on global climate change. This paper attempts to explore international competitiveness of China's iron and steel industry from intra-industry trade flows and associated energy consumption and CO2 emission embodied within these trade flows. China is not only the biggest producer and consumer of iron and steel products but also the biggest exporter and importer of iron and steel commodities in the world. From the perspective of intra-industry trade, China's iron and steel industry is at the bottom of the vertical intra-industry trade. In other words, China has a comparative advantage in primary products as low-tech or low value-added and carbon-rich products along the production chain. Such division of China's iron and steel industry in international trade has contributed a lot to the sharp increase of domestic energy consumptions and carbon emissions of China. In 2007, the energy consumption and the corresponding CO2 emissions embodied in the iron and steel commodities exported from China amounted to 54.3 Mtce and 142 Mtce, respectively, accounting for 11.4% of the total energy consumption and CO2 emission of iron and steel industry in China. In addition, due to the greater carbon-intensity and relatively less efficient production processes of Chinese iron and steel manufacturing, the bilateral trade between China and trade partners resulted in approximately 119 Mt CO2 emission leakage to China. The results presented here have a clear implication for CO2 emission reduction policies. It is suggested that a consumption-based CO2 emission accounting system which subtracts the emissions embodied in exports form domestic production-based inventories and adds the emissions embodied in imports to the consumer economies would be a fairer method of allocating responsibility for emission.

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    Dynamic simulation of central place by using agent-based modeling
    XUE Ling, LUO Bai-yu, WENG Jin
    2010, 29 (9):  1659-1669.  doi: 10.11821/yj2010090012
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    This Paper basically reviews the development of central place theory and its applications and emphasizes the fact that Christaller's theory was based on over-simplifying assumptions and shortcomings such as homogeneity in space, static and close system and empirical observations as equilibriums. Today, the research tendency of geography has changed from static, equilibrium paradigm to dynamic, evolutionary paradigm, which makes use of sciences of complexity to study and analyze the rules of spatial-temporal evolution. New paradigms such as self-organization, evolution theory and complex adaptive system (CAS) have been recognized for a better understanding of the evolutional process of spatial system and its mechanisms. In fact, the basic force driving the evolution of geographic system is inherently microscopic. Therefore, microscopic simulation insists the way in which locally made decisions and interactions between all kinds of local agents give rise to global patterns is highly appropriate. Instead of making nonlinear systems tractable by modeling complex building blocks with few interactions, we can make them understandable by modeling simple building blocks with many interactions based on the central place theory. To further explore the microcosmic foundation of macroscopic spatial structure, a computational environment is developed for better understanding of central place structure by agent-based modeling. The methodology of agent-based modeling (ABM) is a part of the theory of CAS. In this system, a two-tier agent model is built, namely, resident agent and producer agent at a low level and urban agent at a high level. The simulation reproduces and verifies the hexagonal-structure spatial pattern of Christaller by using a genetic algorithm (Genetic Algorithm, GA) on the basis of central place theory assumptions. The result shows that hexagonal macro-spatial pattern is able to emerge from the interactions among the micro agents, which pave the way for the future breakthroughs in homogeneous, static, close hypothesis of Christaller's theory. The paper argues that the hexagonal market area and the central place is a combined result out of economies of scale and transport cost. To probe for the micro-mechanism of the macro-spatial structure requires integrating traditional economic model with agent-based geographical computation.

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    Urban and Rural Studies
    On structural properties of transnational urban network based on multinational enterprises network in China: As the case of link with South Korea
    JIN Zhong-fan
    2010, 29 (9):  1670-1682.  doi: 10.11821/yj2010090013
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    Along with economic globalization and China putting the opening up policy in practice, more and more multinational enterprises entered or went out of China, and established their affiliates, for example, production factories and/or service offices. The multinational enterprises linked Chinese cities with foreign cities by their business network as they carried on their transnational operation. As a result, this transnational urban network was created and developed in China. This paper probed into structural character of transnational urban network of China with South Korea through examining the linkages of headquarters with affiliates of Chinese and South Korean multinational enterprises. The main result of the study can be summarized as follows. First, the urban network developed broadly, including 67 Chinese cities and 67 South Korean cities. Second, the urban network has the property of regional concentration, and network elements such as link bond, linked pair city, network node and node city were mainly concentrated in the Bohai Rim and Changjiang Delta region in China and capital region in South Korea. Third, the linkage density of linked pair city or node city shows the property similar to the rank size distribution, so Qingdao, Shanghai, Beijing and Tianjin with Seoul have formed the main linked pair cities, and Qingdao, Tianjin, Shanghai and Beijing formed the main node cities. Fourth, the linkage density of linked pair city or node city has continually been adjusted, but it kept relatively stable as a whole in the range of higher hierarchy. Fifth, some node cities have been specialized and some have been incorporated in type of industry by multinational enterprises, the former as Beijing and Shanghai, the latter as Qingdao and Tianjin. Finally, the link bond has the property of vector, so the network node was divided into two types, one is source node, and the other is receptive node.

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    Study on the settlement pattern in sandy area and its quality evaluation: A case study of sandy area in the north of Yanchi County
    WU Xiu-qin, ZHANG Yi-xiao, WU Bin, ZHANG Yu-qing, FANG Guang-ling, QIN Shu-gao
    2010, 29 (9):  1683-1694.  doi: 10.11821/yj2010090014
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    Human settlement, permanent community where people live, consisting of buildings, structures, roads, greenbelts and waterhead areas, is usually the shortened form of rural human settlement. In the world, studies of settlements mainly focus on historic geography, the ecological construction and energy ecology.Domestic researches usually study cities with architecture, sociology, ecology and geography, while rural human settlements have not received much attention,especially in the sandy area. This paper analyses the type of settlements in sandy area based on quality evaluation, aiming to choose a suitable land-use pattern of settlement for improving the construction of settlements. In this paper,the sandy area in the north of Yanchi county in Ningxia Hui Autonomous Region is selected as a case. Based on SPOT5 image in the year of 2005, land use map is compiled by interpretation. According to land use map, settlements are divided into 11 types in terms of its spatial relationship with neighboring land and land use pattern, and then the pattern of settlements is identified into three patterns (radial, annular, and radial-annular). Some 30 indicators attached to three systems about the quality of human settlements environment were surveyed in typical settlements of each type in April of 2009, and then evaluation was made by those indicators with the method of mean square error. The result shows that the quality of pattern B (annular) is the best, which has an isolation belt with sandy area (the ring-shaped area); pattern A (radial) is the worst, which is mostly exposed to sandy area directly; type B2 is the finest type with a ring-shaped area, belonging to pattern two; the second is type C3, a complex radial-annular type belonging to pattern three; the worst type is type A2, a radial shape with arable land. In the evaluation, the score of type B2 is the highest, but it is not the best type recommended. As the local rainfall is rare in recent years, water for life mainly relies on water from underground, which is not enough for irrigating all the surrounding areas. Type B2 is typical in the building of a new socialist countryside with preferential policies, so it has enough water to make the surrounding areas to be irrigable land with the project Yang Huang. Considering the practical situation, this type cannot be commonly used in sandy area. Type C3 is chosen as the most suitable type in this paper. In its isolation belt, hedgerows are planted in the upwind direction of the farmland and settlement, which is relatively easy to be realized in sandy area.

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    Study on the index system to evaluate leisure city and its application
    CAO Xin-xiang, MIAO Chang-hong, CHEN Yu-ying, WANG Wei-hong
    2010, 29 (9):  1695-1705.  doi: 10.11821/yj2010090015
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    In order to survey whether a city has the potentials and conditions to develop leisure economy at present, we need to set up a workable evaluation index system and evaluation method to measure the leisure degree and leisure development capacity of a city. This article first analyzed different viewpoints on the Leisure City evaluation index system and summarized the concept and meaning of Leisure City, and then discussed the index system and quantitative method to evaluate Leisure City. With the help of SPSS software, this study took 15 cities in China including Hangzhou, Chengdu, Dalian, Qingdao and Nanjing as examples and analyzed their leisure level and strength. The result showed that Shenzhen, Hangzhou, Chengdu and Beijing had higher leisure consciousness and richer and better leisure facilities, while Xiamen, Shanghai, Dalian and Hangzhou had more appropriate leisure environment. As far as integrated leisure strength was concerned, Beijing, Shanghai, Shenzhen, Guangzhou and Hangzhou had higher leisure comprehensive development degree. Finally, we discussed the issue on how China would build top Leisure City, and put forward some future research proposals on this issue.

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    Geo-information Science
    Application of fuzzy slope positions in predicting spatial distribution of soil property at finer scale
    QIN Cheng-zhi, LU Yan-jun, QIU Wei-li, ZHU A-xing, ZHANG Ling-yan, YANG Lin
    2010, 29 (9):  1706-1714.  doi: 10.11821/yj2010090016
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    The spatial gradation of slope position has a great effect on the soil, hydrological, geomorphic phenomena and processes in small watershed or on slope. The fuzzy slope positions extracted with various methods can quantify the spatial gradation of slope positions and are considered as a kind of promising information to geographic modeling, such as digital soil mapping at finer scale. However, few studies have actually applied the fuzzy slope positions in geographic modeling. This paper attempts to examine the possibility of application of fuzzy slope positions in predicting spatial distribution of soil property at finer scale. In this case, two fundamental assumptions are made as follows: 1) terrain condition which can be comprehensively reflected by slope positions shows most important effect on spatial distribution of soil property in small catchment, and 2) soil property on typical slope position generally represents a typical value when soil property co-varies spatially with slope position. Based on these two assumptions, a weighted average model in which typical values of soil property on typical slope positions are weighted with fuzzy slope positions is developed to predict the spatial distribution of soil property (A-horizon soil organic matter in this study). The fuzzy information of a system of five slope positions (i.e., summit, shoulder slope, back slope, foot slope, and valley) was derived by a method based on typical locations of slope positions. The weighted average model was evaluated in a low-relief catchment (about 60 km2) of Nenjiang watershed in Heilongjiang Province, Northeast China. The multiple linear regression model based on topographic attributes was also applied to comparison of model performance. Three indices, i.e. correlation coefficient between predicted and observed values, mean absolute error (MAE) and root mean square error (RMSE) based on a validation set of 70 soil samples were calculated for quantitative assessment of the model performance. Results show that the weighted average method with very few modeling points can better predict the spatial distribution of A-horizon soil organic matter than the multiple linear regression model does.

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    Design and realization of virtual tourist landscape based on VRML_ArcGIS
    JIANG Wen-yan, LUAN Ru-peng, ZHU Xiao-hua
    2010, 29 (9):  1715-1723.  doi: 10.11821/yj2010090017
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    Virtual tour is designed based on the virtual reality technique platform, Internet or other vehicles. The travel landscape is dynamic and vividly presented in front of tourists. Tourists may choose tour route and view speed and viewpoints by themselves. Virtual tour will play an important role in propagandizing, protecting and reproducing scenes and decision-making support. Currently, virtual tour system on the development of research methods are more broadly grouped into four categories: 3D panorama, VRML/X3D language programming methods (such as DirextX, OpenGL), Web3D business software. These methods achieve results, ease of extent and scope of preferences for different applications, each with merits and demerits. Virtual tourist attractions are composed of virtual ground model and the virtual features model. The virtual ground model has geographical features, only located in the virtual scene to reality; virtual features model is needed to simulate the reality, allows users to carefully watch from outside to inside. At the same time, virtual tourist landscape is needed to balance fidelity and display speed, which are also the shortcomings and a major technical difficulty of virtual tour. Virtual tour is the tourism-oriented virtual reality platform on network using 3D-GIS, virtual reality and network technologies. Throughout the building of virtual tour system, the most basic and most important part is the realization of virtual tour landscape, which is related to display effect and display speed of the virtual landscape, as well as the realization of spatial analysis, simulation scenarios and the other functions. Based on the characteristics and realization difficulties of virtual tour landscape, the paper separately built virtual ground and virtual features using ArcGIS and 3DSMax, which have different configuration characteristics. All the models were transformed to VRML file format, and the VRML files were optimized through many methods. Which not only effectively fused virtual ground models and virtual features models, but also gave attention to the fidelity and display speed of models. The paper advanced a suit of design program and key technology of virtual tour landscape, and validated it through exploiting virtual tour landscape of Yuanmingyuan Ruins Park. The paper formed research and exploiting methods and technology of virtual tour, which could provide strong support of digital, virtual, high-tech information methods and means.

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