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  • Orginal Article
    CHEN Guixiang,GAO Dengzhou,ZENG Congsheng,WANG Weiqi
    Journal of Geo-information Science. 2017, 19(2): 216-224. https://doi.org/10.3724/SP.J.1047.2017.00216
    CSCD(7)

    It is very important to study the characteristics of spatial pattern and variation of soil nutrients and analyze the effect of topographical factors on the spatial distribution of soil nutrients for the effective use and management of soil nutrients. In this paper, the combination of GIS and Geostatistics methods were applied to analyze the spatial distribution characteristics and variation pattern of soil nutrients (organic matter, available nitrogen, available phosphors and available potassium) in the agricultural land of southeast hilly area of Fuzhou. We further studied the correlation between soil nutrients content and topographical factors (topography degrees, elevation, topographic wetness index, deposition and transport index and gradient). The results showed that: the range of organic matter, available nitrogen, available phosphors and available potassium contents were between 1.10~89.5 g/kg, 1.00~461 mg/kg, 0.300~298 mg/kg, 4.00~399 mg/kg and the range of variation coefficients were 35.3~99.0%, which belonged to moderate variability. There was obviously different in the spatial abundance of soil nutrients in the cultivated land. In most of the area, the organic matter and available phosphors content were abundant, available nitrogen content was a little above average level and available potassium content was relatively scarce. The nugget coefficient of organic matter, available nitrogen, available phosphors and available potassium were 32.0%, 37.3%,50.0% and 50.0%, respectively. They were medium spatial autocorrelation, indicating that they were controlled by structure and randomness. Spatial autocorrelation scale of organic matter and available nitrogen were large. They change smoothly in each direction (0°, 45°, 90° and 135°) when the step length was less than 0.3 km.and are isotropic. The variation of effective phosphorus and available potassium was small. Their direction of change was complex and they are anisotropy. These results suggested that the government needed to strengthen guidance of fertilization. Nitrogen fertilizer amount should be maintained and the potash should be increased reasonably. The organic fertilizer and phosphate fertilization should be decreased.. In addition, in the subsequent investigation, the setup of sample points should consider density and direction and appropriately increase the sampling of effective phosphorus and available potassium while nitrogen and organic matter and alkali solution sampling can be reduced based on the study.

  • ARTICLES
    WU Qunyong, WANG Qinmin, ZHOU Chenghu, CHEN Chuanbin, HUANG Ruiyin
    . 2007, 9(4): 85-88.
    GML(Geographic Markup Language) is gradually accepted and widely used as an encoding,storage and exchange format for spatial information,and it offers a powful tool for implementing spatial information sharing and WebGIS development. As a graphic file format standard in the network era,SVG(Scalable Vector Graphic) represents graphic transmission development direction on the web,which integrates vector graphic,bitmap image and plain text merits and is naturally compatible with the network environment,so study on GML and SVG-based WebGIS and its application will have extensive practicality and application value. In this paper,GML and SVG are discussed firstly,especially in the role of open WebGIS,then an open WebGIS architecture is put forward which uses GML to store and integrate geographic information and using SVG to implement web display and operation for geographic information. Finally,taking a campus map issuing system as an example,an open WebGIS application system is set up and discussed.
  • ARTICLES
    YUAN Jinguo, WANG Wei
    . 2005, 7(3): 97-103.
    CSCD(11)
    Multi-source remote sensing data fusion is the development trend of remote sensing technology in depth. This paper analyzes in detail algorithmic application characteristics of multi-source remote sensing data from three levels of pixel-based, feature-based and decision-based fusion processings. Take Fengning County for example, specific applications of remote sensing data fusion methods in information extraction are illuminated. The data used in this study is firstly pre-processed, then the principal components of Landsat TM data in 1999 are analyzed, the first three principal components account for 97.8% of the total information, the resulted image of inversed principal components transformation is clearer and has more abundant levels. To extract information from remote sensing image, we select the fusion image from Landsat TM pan and multi-spectral bands after principal components transformation, color composition scheme of bands 4, 3, 2 and bands 5, 4, 3, and vegetation index and greenness index after tasseled cap transformation are analyzed, the remote sensing image information fusion with DEM and spatial data of GIS database can also improve the accuracy of remote sensing information extraction. Problems to be resolved and future direction of multi-source remote sensing data fusion are put forward.
  • DUAN Weifang, WEN Xiaole, XU Hanqiu, DENG Wenhui
    Journal of Geo-information Science. 2022, 24(12): 2435-2447. https://doi.org/10.12082/dqxxkx.2022.220184

    In the summer of 2020, heavy rains made the Poyang Lake region witnessed a big flood event. Remote sensing earth observation technology can help to map and assess the flood hazard quickly and efficiently. Therefore, two 2020 satellite images acquired on April 15 (Landsat-8 OLI) and July 14 (Sentinel-1A SAR) were selected in this study to represent the dates before and after the flood to evaluate the disaster. Using remote sensing thematic information extraction, Random Forest classification and change detection technology, the inundation area and the area of major land cover types within the inundation areas were revealed. Associated with the hydrological, meteorological and topographical data, the specific flooded sites and the factors causing the disaster were identified and analyzed. The results show that the flood-inundation extent in the Poyang Lake region in 2020 is 1961.95 km2, including 760.54 km2 of farmland, 71.59 km2 of forest, 992.02 km2 of grassland, 26.97 km2 of soil, and 110.83 km2 of built-up land. Poyang County was most severely affected in this flood event, with a total inundated area of 514.35 km2. The next two are Xinjian County with 330 km2 and Yugan County with 310 km2. The main hydro-meteorological and topographical factors that caused the flood are considered to be: (1) higher water level than that in the 1998 flood; (2) failure of timely discharge of water due to backflow of the Yangtze River; (3) breach of the embankments.

  • ARTICLES
    WANG Shu, JI Lei-Jing, ZHANG Xue-Yang, DIAO Ren-Liang, CHEN Xiao-Dan, TU Gao
    CSCD(7)

    Geographic features change detection has became a vital component of the national geographical information 12th Five-Year-Plan and the national geographic general survey. In web pages, billions of geographic feature changes were contained, especially in government official websites, news homepages, social portals and etc. The web pages of these websites update frequently, which could provide the latest data for geographic infor-mation change detection. Considering the complex characteristics of the web geographic information description, this paper did some valuable achievements. First of all, the geographic information knowledge base was established by summarizing the geographic information words and phrases, which could give the great supports to geographic information semantics change detection. Then, the web geographic information was obtained using two kinds of web crawler technologies. Combining the Google Custom Search crawler and general topic crawler, the web geographic information obtainment could be more complete in both scope and depth. Thirdly, the geographic information was parsed and extracted from the web text, which showed users the related features, place names, times and attributes. Last but not least, the prototype system was finally developed and the results were analyzed. The experiments indicated that the accuracy of related web pages obtainment and features change detection were over 74% and 70% respectively. In addition, the results of geographic information change detection highly relied on the integrity of knowledge base, which need to be completed further. Moreover, the uncertainty and fuzziness of web geographic information also limited the change detection results. Therefore, the web page based geographic information change detection could be a supplementary method of geographic information change detection. Combining the traditional surveying detection and remote-sensing imagery detection methods, it could solve the problems of continuous updating and timely updating of geographic information efficiently.

  • Orginal Article
    CHEN Tianbo,HU Zhuowei,WEI Lai,HU Shunqiang
    Journal of Geo-information Science. 2017, 19(5): 692-701. https://doi.org/10.3724/SP.J.1047.2017.00692
    CSCD(10)

    The high-resolution DEM and DOM data is an accurate description of the topography and geomorphology, and it is also an important source data for landslide information extraction. At first,according to the requirement of landslide information extraction,we use the UAV platform equipped with mini SLR camera combined with the GPS data measured in the field, as the image acquisition method. According to the characteristics of the UAV images, we use the basic principle of photography measurement and computer vision algorithms to obtain the high-resolution DEM and DOM images, which greatly preserves the rich spectral and texture information. Then, with the help of the ESP auxiliary tool we get optimal segmentation scale of the DOM. Based on the fuzzy classification and SVM algorithm to construct a decision tree, which we used to achieve the object oriented classification and information extraction. Finally, according to the spatial feature and distribution of study area we determine the high risk area. By the morphology and texture analysis and accuracy assessment of the landslide area, we show that the producer’s accuracy and user's accuracy of the landslide area are 84.65% , 91.44%. The result proves that the UAV remote sensing has a high value in the field of landslide information extraction.

  • ARTICLES
    ZHAO Yanqing, CHEN Rongguo, YUAN Lin
    . 2010, 12(5): 674-679.
    CSCD(2)
    Because spatial data has the features of spatial position,unstructured,spatial relationship and vast amount etc,memory access performance on spatial data becomes one of the most important indexes for geo-spatial database evaluation.BeyonDB,researched and developed under the support of National "863" Program,is the geo-spatial database system with independent intellectual property rights.Because at present,there is no software supporting performance comparison test of geo-spatial database and in order to objectively assess its performance index,it is necessary to design,research and develop a kind of performance comparison test software of geo-spatial database.Functional objectives of performance comparison test software of geo-spatial database are firstly analyzed in the paper,i.e.to support performance comparison test between BeyonDB and international leading geo-spatial database system,meanwhile,it can simply extend into other geo-spatial database;to support performance test of loading and inquiring of spatial data;to support testing methods of both SQL sentence and test script,and test report should be automatically generated and output based on "Template" method.As to performance comparison test software of geo-spatial database,we adopt object-oriented design philosophy and method,rationally use software design pattern.General framework design of the software and detailed design of main control,function command interface,access interface of spatial data and output of test results etc.are provided in this paper.After completing the design,we put forward methods of realizing functions of the software,development tool,main interface of the software,output interface of test results and other results.At present,the software has been successfully applied to performance comparison test between BeyonDB and Oracle Spatial,BeyonDB and PostGIS,which greatly improves test efficiency and enables test results to be objective and impartial.Finally,future research emphases of the software are defined in the paper.
  • ZHAO Qunqun, ZHAO Jing, ZHANG Lingxian, WANG Tuo, YANG Tengfei, ZHAO Chen, MOU Naixia
    Journal of Geo-information Science. 2024, 26(6): 1439-1451. https://doi.org/10.12082/dqxxkx.2024.230685

    Due to technical gaps in using satellite carbon observations for regional emission reduction, high-resolution, global-scale Fossil Fuel Carbon Dioxide (FFCO2) emission inventories have become the main data sources for regional FFCO2 emission research. However, there are still significant uncertainties in use of existing global-scale FFCO2 emission inventories for regional research. Therefore, this paper quantitatively analyzed the differences and variabilities of high-resolution FFCO2 emission inventories (ODIAC 2020b, EDGAR v6.0, and PKU-CO2-v2) at the regional scale and fused these three inventories based on Kalman filtering algorithm. Then, this paper explored the spatial and temporal evolution pattern of FFCO2 emissions in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA). The results show that: (1) There were significant differences and variability among the current FFCO2 emission inventories. Taking the GBA as an example, under the optimal representation spatial resolution of 3 km × 3 km, the average difference of grid cells within the region reached 140%, and the coefficient of variation was 16.3%. The use of a single global scale FFCO2 emission inventory data for regional or urban FFCO2 emission studies resulted in inaccurate results; (2) The reconstructed long term data from 2000 to 2018 using Kalman filter showed that the uncertainty decreased from ±15%~20% to ±10%; (3) From 2000 to 2018, the overall pattern of FFCO2 emissions in the GBA was characterized by high emissions in Guangzhou, Shenzhen, Hong Kong, and Macao, low emission areas in the peripheral areas, and an emission transfer path from Shenzhen, Hong Kong → Guangzhou → Foshan, Dongguan → Zhongshan. The approach for regional FFCO2 emissions proposed in this paper is demonstrated in the GBA and is applicable to other regions and cities. The conclusions of this research will provide a scientific basis for the optimal layout of energy and resources in the Greater Bay Area, which is of great significance for low-carbon transformation, high-quality development, and the construction of Beautiful Bay Area.

  • Orginal Article
    ZHAO Zhujun,JI Genlin
    Journal of Geo-information Science. 2017, 19(3): 289-297. https://doi.org/10.3724/SP.J.1047.2017.00289
    CSCD(5)

    Spatial-temporal trajectory classification aims at predicting the category of a spatial-temporal trajectory. The classification of spatial-temporal trajectories plays an important role in urban planning, personalized user recommendation and so on. The process of trajectory classification includes three stages: trajectory preprocessing, feature extraction and classification. This paper reviews the recent research progress on trajectory classification. Firstly, we introduce the process of trajectory classification. Then, the trajectory classification algorithms are classified into three categories according to the method of feature extraction, including the trajectory classification algorithm based on motion feature, the trajectory classification algorithm based on classification rule and the trajectory classification algorithm based on image signal analysis. We also discuss the basic ideas, advantages and disadvantages of these algorithms. Thirdly, we compare the existing classification algorithms according to the sensors, feature extraction and classifiers used in these algorithms. Finally, we introduce the challenges of the existing trajectory classification algorithms.

  • Orginal Article
    MA Junting,CHEN Suozhong,ZHU Xiaoting,HE Zhichao
    Journal of Geo-information Science. 2016, 18(6): 749-757. https://doi.org/10.3724/SP.J.1047.2016.00749
    CSCD(1)

    The existing finite element numerical simulation method of groundwater flow has some defects in the three-dimensional visual spatial analysis and the expression of numerical calculation process and simulation results. In order to solve this issue, the key steps of the finite element analysis process including the conceptual model construction, spatial discretization, hydrogeological parameters extraction and initial condition assignment are taken into consideration respectively. Based on the finite element method and 3D GIS platform, the method and technique framework of the groundwater finite element numerical simulation under 3D GIS are proposed with the supports of GIS spatial analysis algorithms and computer graphics theory. In addition to describe the technique framework, the core algorithms’ implementation details are given and the complete process of 3D GIS groundwater flow simulation is presented. The groundwater simulation example demonstrates that the proposed method and technique framework are capable of simplifying the finite element analysis process and improving the calculation efficiency of the model. The whole technique framework can be integrated into 3D GIS platform, and furthermore the visualization of simulation process and calculation results can be achieved eventually.

  • Li Zhi,Yang Xiaomei,Meng Fan,Chen Xi,Yang Fengshuo
    Journal of Geo-information Science. 2017, 19(11): 1522-1529. https://doi.org/10.3724/SP.J.1047.2017.01522
    CSCD(3)

    The urban built-up area boundary is important basic information for urban studies, and is also the premise of the implementation of urban function space layout, the implementation of boundaries control. Accurate extract urban built-up area for urban construction, management and research has important guiding significance, but also reflects the city's comprehensive economic strength and the level of urbanization, one of the important indicators.The DMSP/OLS night light data has been widely used in the extraction of urban built-up areas. But due to the effects of saturated, diffuse, and low resolution problems, it is still a huge challenge to rely on the DMSP/OLS NTL mapping the urban built-up areas. In order to overcome the limitations of the data source itself, In this study, the application of hierarchical expert knowledge analysis, multi-source data extraction of the thematic information layer by layer into the extraction process, the construction of urban built-up area for the level of expert knowledge model to achieve the city built-area refinement extraction. The urban index (VANUI) was constructed by combining 250 m MODIS NDVI data with 1 km DMSP/OLS data. Based on the administrative boundary, the statistical area of the area is divided into the administrative boundary of each prefecture-level city, and the optimal segmentation threshold of each administrative unit VANUI feature image is calculated according to the regional segmentation method, so as to obtain 250 m urban boundary space information range. Meanwhile, Due to the low spatial resolution of the DMSP/OLS luminous data and the narrow range of light and light values, there is still a large gap between the optimal segmentation threshold and the built-up area. Therefore, this study proposed the maximum autocorrelation double threshold extraction method. The 30m Landsat 5 NDVI data were fused to obtain the maximum autocorrelation quadratic NDVI threshold in each 30m seed region by multi-scale segmentation of the regional threshold segmentation. According to the maximum autocorrelation threshold of each potential built-up area, each potential built-up area is revised one by one, and finally 30m urban built-up area is obtained. This paper takes the Beijing-Tianjin-Hebei region as the research area, the experimental results show that the total precision of extracting urban built-up area by multi-source remote sensing cooperative method is 92.9%, and it has higher validity and reliability in spatial distribution and statistical data. The results show that the results of the urban built-up area extracted by this method are not only the overall accuracy, but also the spatial extent of the visual interpretation, and the relative error of the statistical area in each prefecture-level city is small, which verifies the reliability and validity of the method in spatial distribution and statistical data, and avoids the error caused by subjective threshold selection. DMSP/OLS data can be used not only for urban area extraction, but also for the intensity and scope of human activities. Therefore, in the follow-up study, based on the identification of urban built-up area boundary, combined with the quantitative analysis of luminous data and evaluation of urban development area outside the expansion trend and internal dynamic changes for the DMSP/OLS luminous data to give full play to its effectiveness, Economic and historical values play a positive role in promoting.

  • ZHAO Yanchuang,ZHAO Xiaofeng,LIU Lele
    Journal of Geo-information Science. 2016, 18(8): 1094-1102. https://doi.org/10.3724/SP.J.1047.2016.01094
    CSCD(3)

    Heatwave has become an extreme meteorological disaster which occurred frequently during the summer. Moreover, heatwave could evidently affect the healthy conditions of residents. Thus, study the spatial pattern of heatwave health risk would be helpful for us to prevent from and respond to the impacts of heatwaves. Using the historically meteorological datum of Xiamen, this study built a database of heatwave cases and analyzed the basic characteristics of heatwaves in Xiamen. Taking a heatwave event occurred in 2010 as a case, we analyzed the spatial pattern of heatwave health risk by using both the remote sensing data and the demographic data. It is concluded as the following statements. (1) The intensity of heatwaves in Xiamen is quite low, but its frequency is rather high. An intensive heatwave occurred occasionally. (2) The regions with high health risk are located in Xiamen Island, lying from the northeast toward the southwest. The regions with the highest healthy risk are located in the northern and southeastern Jiangtou sub-district, Huli district, and the most area of Xiagang sub-district and Siming district. (3) The human health risk pattern of Heatwave is associated with the spatial distribution of environmental and demographic factors. Generally, this study promotes and extends the scientific knowledge on the health risk of heatwaves.

  • HOU Xiyong,DI Xianghong,HOU Wan,WU Li,LIU Jing,WANG Junhui,SU Hongfan,LU Xiao,YING Lanlan,YU Xinyang,WU Ting,ZHU Mingming,HAN Lei,LI Mingjie
    Journal of Geo-information Science. 2018, 20(10): 1478-1488. https://doi.org/10.12082/dqxxkx.2018.180184
    CSCD(6)

    Land use mapping using remote sensing techniques supplies essential datasets for scientific researches including global climate change, regional sustainable development and so on. The evaluation information on the accuracy of the land use mapping determines the integrity, reliability, usability, controllability and shareability of the land use maps obtained by the applications of remote sensing techniques. In this paper, the methods, processes and results of multiple temporal land use mapping for China's coastal zone using remote sensing techniques were overviewed, and the land use maps in 2010 and 2015 were selected for accuracy evaluation. The validation samples were collected based on Google Earth and the confusion matrices were established for the whole coastal zone and its sub-regions, respectively. Then, the overall accuracy and Kappa coefficient were calculated. Main findings are as follows: (1) Results of land use mapping in 2010 and 2015 using remote sensing techniques achieved high accuracy. For the entire coastal zone in China, the overall accuracy came to 95.15% and 93.98%, with the Kappa coefficients of 0.9357 and 0.9229 in 2010 and 2015, respectively. (2) The accuracy of land use mapping in China's coastal zone exhibited obvious regional differences. The best accuracy was found in the coastal area of Jiangsu province in 2010, and very high accuracy were found in the coastal area of Hebei-Tianjin, Shanghai city, Hainan province and Taiwan province in 2015, while the worst accuracy was found in the coastal area of Fujian province in both 2010 and 2015. (3) The accuracy of land use mapping in China's coastal zone exhibited obvious typological differences. The very high accuracy (both producer precision and user precision) were achieved for farmland, forest, grassland and saltwater wetlands, and the high accuracy for built-up, freshwater wetlands and human made saltwater wetland, while the worst accuracy for unused land. (4) The misclassification between cultivated land and forest land, construction land and grassland is quite significant. Inland water bodies were easily misclassified into cultivated land, forest land and construction land. Artificial salt water wetlands were easily misclassified into cultivated land and construction land, and unused land. It was easy to mistakenly classify the unused land as cultivated land. These are the issues that should be paid more attention during the continuous update of the land use maps in the future. This study provides supports for the dynamic monitoring and scientific researches on coastal land use changes.

  • Orginal Article
    Wan HOU, Xiyong HOU
    Journal of Geo-information Science. 2019, 21(7): 1061-1073. https://doi.org/10.12082/dqxxkx.2019.180441
    CSCD(1)

    Land Use and Land Cover (LULC) classification products play an indispensable role in ecosystem assessment, climate change simulation, national geographical condition monitoring, and macro-control policy analysis at the global scale; consistency analysis is the precondition of applying various LULC classification products. This paper assessed the area consistency and spatial consistency of five LULC classification products - MCD12Q1-2010, GlobCover2009, CCI-LC2010, FROM-GLC2010 and GlobeLand30-2010- in the global coastal zones. The five products were compared in terms of the deviation coefficient, correlation coefficient, error matrix, and spatial confusion of LULC types. The main findings are as follows: (1) The spatial patterns of LULC in five products demonstrate relatively strong overall consistency, but can have significant local inconsistency. (2) The five products are qualitatively consistent yet quantitatively inconsistent in classifying the LULC in the global coastal zones ? in terms of structure, water ranks top one, followed by forest and unused land, next are farmland, grassland and shrubland, and lastly wetland and artificial surface, yet the exact area of each LULC type differs among different products. (3) For the correlation coefficient, overall accuracy and Kappa coefficient, MCD12Q1-2010/GlobCover2009 have the minimum values, 0.8814, 67.46% and 0.5748, respectively; while GlobCover2009/CCI-LC2010 have the maximum values, 0.9869, 81.50% and 0.7505, respectively; it is because GlobCover2009 and CCI-LC2010 obtained from the same production organization have the same classification system, while MCD12Q1-2010 is different from GlobCover2009 in terms of the production organization, data source, classification system, and classification method. (4) For the spatial confusion/misclassification between any two different products, grassland, shrubland, and wetland have the highest mix-up ratios, followed by farmland and artificial surface, and lastly forest, unused land, and water; this difference is because forest, unused land, and water have distinctive spectral characteristics and clear spatial textures, while grassland, shrubland, and wetland have similar spectral characteristics and fuzzy spatial distributions. (5) There are 28.81% land area in the global coastal zones with relatively low consistency, i.e., with severe spatial confusion; specifically, the misclassification of farmland, forest, grassland, shrubland, wetland, and unused land has direct influence on the spatial consistency of the five products. This paper is hoped to serve as a reference of selecting data from the five available LULC products for researching coastal zones.

  • ARTICLES
    TANG Zhihua, ZHU Xianlong, LI Cheng
    Based on the principle of the CLUE-S (the conversion of land use and its effects at small region extent) model, taking Yangzhou City area as an example, we firstly collected the required data, including basic geographic data (vector data and image data) and statistics data, then preprocessed the image data, including ETM images in 2001 and ALOS images in 2007, and took use of object-oriented information extraction method to obtain a land use map for two periods (2001 and 2007). We selected the driving factors and used GIS spatial analysis tools to get a variety of spatial distribution of all the driving factors, set the model parameters, and took the land-use map in 2001 as the model input data to simulate the spatial pattern of land use of 2002-2007 in Yangzhou City area. Finally, we obtained the actual land use map of 2007 in Yangzhou City area by using the object-oriented data extraction method, and tested the simulation results of 2007 in Yangzhou City area and analyzed the applicability of the CLUE-S model. The result shows that the CLUE-S model could simulate preferably the spatial distribution pattern on a small-scale. Therefore, it could provide guidance for small city planning. So the CLUE-S model is one of the land use/land cover change models that worth to be made more widespread.
  • ARTICLES
    TANG Li-Yu, LIN Ding, HUANG Hong-Yu, JU Jie, CHEN Chong-Cheng, DU Yun-Hu
    CSCD(2) Crossref(1)

    Energy fixation and organic matter production of forest ecosystem were dominated by plants, which are impacted by their growth environment. The forest ecosystem has the characteristic of long life-span, which makes its research laborious and costly using field experiment. The virtual geographical environment can provide a new way for its research due to its character of trying to exceed the limit of time and space. In order to estimate the biomass and evaluate relationships among tree and environments, an L-systems based functional-structural model was developed for simulating the development of tree architecture, taking into account tree physiology and environment. The L-systems was used to represent the morphological development of tree. The basic growth unit was described in line with the development of young Chinese fir (Cunninghamia lanceolata). LSTree system integrated the photosynthesis, photosynthates allocation and morphogenesis models. The spatial distribution of solar radiation in tree canopy was simulated for calculating photosynthetically active radiation (PAR) of each leaf obtained. PAR is a key parameter for photosynthesis model to estimate biomass. The dynamic growth of an individual 3-to-4-year-old Chinese fir in Fuzhou was simulated in growing season. Based on the 2010 Fuzhou weather and Chinese fir photosynthetic characteristic, net photosynthesis rate and product were calculated for each stage. The amount of photosynthates allocated to the growth of new segments and leaves or branches and leave amplification are based on source-sink theory. The growth of tree is driven by available photosynthetic products after respiration losses were accounted for. The morphogenesis change in the young Chinese fir in response to environment was simulated dynamically in three dimensional representations. The result of net photosynthesis was compared to the previous field observation research, and it showed the simulation result was reasonable. The methodology has promising benefits to depicting the interaction of plant and environment, which will be valuable for estimation of organic matter production too.

  • ARTICLES
    MN Sweeting, CHEN Fang-Yuan
    . 1997, 0(1): 71-77.
    自然和人为的灾害每年都使远东的中国和她的周边国家蒙受了巨大的经济损失。为了能快速地对这些灾害作出反应以减少损失,有效和及时地从外层空间监测灾害已成为了一项迫切的国家需要。为了改进现行系统的覆盖范围和覆盖周期,曾建议采用地球观测卫星网。然而,常规遥感卫星的高成本至今还使得这项建议难以实施。萨瑞大学的萨瑞卫星技术有限公司(SSTL)已经研制了一套性能高、寿命长的微型卫星,该卫星利用先进的对地观测有效载荷,具有较强的星载处理能力。利用该套卫星就可以极低的成本获得从空中对地球的常规观测。每颗微型卫星只需费用约250万美元,因此,投资不到1800万美元就能构建由7颗卫星组成的卫星网(星座)。微型卫星重量轻、体积小,只需一个小的发射器就可以把整个网发射到低地球轨道中。
  • HE Bin, WU Wenzhou, KANG Lu, SU Fenzhen
    Journal of Geo-information Science. 2021, 23(11): 2013-2024. https://doi.org/10.12082/dqxxkx.2021.200770

    In recent years, with the continuous exploitation and utilization of marine resources, marine spatial planning has become more and more important, among which fishery resources account for the main proportion. In order to provide auxiliary information for the monitoring and planning of fishery resources, this paper obtained the 2018 Automatic Identification System data of the South China Sea and surrounding countries, extracted the activity intensity of fishing vessels and carried out preprocessing, sampling processing, and GIS spatial analysis, and then mathematically analyzed the spatial and temporal characteristics. The results showed that, firstly, in 2018, fishing vessels in the South China Sea and surrounding countries were mainly distributed regionally, concentrated in areas within 100 km of the coast of China and Vietnam. Fishing activities were frequent in autumn and November. The average activity intensity of fishing vessels was higher during the day than at night, with the maximum activity intensity at 16:00 PM; Secondly, the intensity of fishing activities in main ports of Guangdong, Guangxi, and Hainan provinces is clustered as dots, with the intensity of fishing activities bigger than 100. The sea area near some ports is striped, and the intensity of activities of other fishing vessels in the South China Sea is larger than that of other islands in the Paracel Islands. The activity intensity of fishing vessels is smaller than 2; Thirdly, the regional distribution of Vietnamese fishing activities is obvious, showing a stable mass clustering distribution in Ho Chi Minh Port, with little change in activity intensity throughout the year. The activity intensity of nearshore fishing vessels remains at 50~100. Vietnamese fishing vessels are banned in the South China Sea. There are two areas with strong activity in the southwestern part of Hainan Province within the fishing line. In 2018, days with fishing activity accounted for 87.71% of the total sampling days, with on average 7~10 fishing boats every hour in the area. During the moratorium period, the average number of boats every hour is bigger than 5, which poses a great threat to China's south China sea fishery resources. In this paper, AIS data research and analysis of fishing vessel activities can provide data support for marine spatial planning and relevant government departments.

  • TAN Cui, HUANG Qin, YANG Bo, LI Tao, LEI Jihua
    Journal of Geo-information Science. 2024, 26(2): 318-331. https://doi.org/10.12082/dqxxkx.2024.230198

    The ecotourism suitability assessment is the basis and a crucial reference for evaluating development potential, formulating plans, and implementing exploitation in ecotourism. In this study, we first analyze the feasibility of machine learning methods for modeling ecotourism suitability, and the Random Forest (RF) algorithm is selected for conducting an empirical study in the Wuling Mountain area in Hunan Province. In the study area, there are abundant tourism resources with an urgent need for ecotourism development, which can not only consolidate and expand the achievements of poverty alleviation, but also effectively connect with rural revitalization, thereby promoting sustainable development of tourism. The results show that: (1) Machine learning, as a new regional ecotourism suitability assessment approach, provides new insights and solutions for further improvement of suitability assessment; (2) The RF algorithm as a typical machine learning method can be effectively applied in the regional ecotourism suitability assessment. The optimized RF model achieves an average testing accuracy of 86.49%, with an area under the curve (AUC) of 0.95. These results also indicate the ecotourism suitability of the Wuling Mountain area in Hunan Province; (3) The ranking of feature importance reveals that land use type contributes most to the model, accounting for 28.98%, followed by other significant factors including population density (16.34%), distance from scenic spots (12.2%), and biological richness (10.65%). The above factors should be all considered in ecotourism development efforts; (4) The ecotourism suitability results show a high proportion of highly and moderately suitable areas, suggesting significant potential for ecotourism development in the study area. Based on the ecotourism suitability assessment, different development directions are proposed: A protective pattern and experiential education-oriented ecotourism are well-suited in highly suitable areas; a joint pattern and supportive ecotourism are appropriate for moderately suitable areas; a restrictive pattern is recommended for marginally suitable areas; and for unsuitable areas, the development should be prohibited. Finally, we present a new development strategy known as "two centers, one belt, and one plate," providing theoretical and technical guidance for ecotourism development and the consolidation of poverty alleviation achievements in the Wuling Mountain area of Hunan Province.

  • ARTICLES
    XIE Ru-Tang
    . 1998, 0(1): 9-10.
    我代表建设部祝贺全国地理信息系统技术与应用工作会议的召开,感谢国家科委长期以来对建设部科技工作的大力支持。建设部在城市规划领域应用地理信息技术取得了一定成绩,下面我简要介绍一下有关情况。 建设部是国务院综合管理全国建设事业的职能部门,其中一项重要职责是指导和管理全国的城市规划工作。建设部十分重视地理信息系统技术在城市规划领域中的应用,并给予积极支持和引导。地理信息系统技术在城市规划领域得到较好地应用、推广,并取得明显成效,这与城市规划在城市现代化建设中的地位和作用密切相关。
  • Orginal Article
    DU Guoming,SUN Xiaobing,LIU Yansui,ZHENG Huiyu,MA Ronghui
    Journal of Geo-information Science. 2017, 19(3): 355-364. https://doi.org/10.3724/SP.J.1047.2017.00355
    CSCD(2)

    Ecological restoration is an important way to adjust the structure and function of ecosystem in order to cope with the excessive interference of land use. Scientific mastery of restoration pattern and farmland pattern evolution has a profound significance on the management of regional ecological environment and the conservation of vegetation in Loess Plateau. This study, taking Yan'an City in Loess Plateau as a typical area, explores the spatial differentiation characteristics of farmland variation and restoration status from the overall characteristics of ecological restoration, topographic factors and regional differences since ecological restoration. The results show that the arable land of Yan'an City decreased from 11752.80 km2 to 9149.93km2 due to the ecology restoration during 2000-2013. The returned farmland is 2756.85 km2, and the returned farmland index is 22.15%. The cultivated land was mostly converted to forest and grassland accounting for 95.29% of the total amount. Farmland and the returned farmland area was mainly distributed in slope (6~25°) and the altitude level of II(925~1115 m), III(1115~1275 m), IV(1275~1442 m), which accounted for more than 70% of the area. The degree of farmland returning increased gradually with the increase of slope, with the land reclamation rate decreased gradually with the increase of slope and elevation. The highest degree of ecological restoration is the altitude level of IV, and the least is altitude level of III. The ecological restoration rate of 2005-2013 was higher than that of 2000-2005. The area and extent of restoration in county decreased from north to south. The center of farmland returning and cultivated land is located in the boundary of Ansai county and Baota District which are in the north of Yan’an City. The center of ecological restoration was changing from northeast to southwest while the center of cultivated land was changing from north to south. This study may provide more scientific and reasonable reference for ecological conservation and construction of ecological civilization in Loess Plateau by the analysis of spatial-temporal differentiation characteristics of ecological restoration in Yan'an city.

  • ARTICLES
    ZHANG Tianyu, ZHOU Chenghu, SHAO Quanqin
    . 2003, 5(4): 25-29.
    CSCD(5)
    Marine GIS has become one of the important developing domains of GIS sciences Both scholars in GIS and in oceanography are interested in it The basic representation is considered as one of the most important problems This article presents a data model to solve the problem It includes three database: basic database, data warehouse and database for marine phenomena; two data analyzing mode: data pre disposing and feature analyzing It uses multi level extended grid data structure with two kinds of global grid scheme One is equal angle, the other is equal area grid scheme They have some new marine chara cteristics.
  • ARTICLES
    CHENG Lin, WANG Meiling, ZHANG Yi
    . 2010, 12(5): 649-654.
    Path planning is a process to find the optimal path from the starting node to the destination node.Tens of algorithms have been designed to resolve the shortest path problem,in which the Dijkstra algorithm is always thought to be the most mature and classical one.However,its higher time complexity greatly restricts its practical application.Besides,for most path planning algorithms,the road network is considered as an ordinary plane network and the spatial distribution characteristics are ignored,therefore,the path planning algorithm can not do well in real road network.In order to improve the searching efficiency of the traditional Dijkstra algorithm and to meet the requirement of real-time vehicle navigation,a path planning algorithm based on SuperMap is designed by utilizing the network editing function of SuperMap GIS platform.Firstly,with the spatial distribution characteristics,a road network is built in SuperMap.In this process,we take three-dimensional transport and one-way road network into consideration,making the road network built in SuperMap able to reproduce the real road network.For three-dimensional transport,we set the parameters of non-broken lines and make sure the roads not in the same plane have no intersections;for one-way roads,the forward resistance and reverse resistance are set with different weights.Secondly,in order to improve the searching efficiency of the traditional Dijkstra algorithm,we propose a method to restrict the searching area.According to the coordinate relationships of the starting node and the destination node,we create a hexagon area,which contains the staring node and the destination node,as the restricted searching area,and make the algorithm able to search the shortest path within the restricted searching area on the theoretical basis of the classic Dijkstra algorithm.Thirdly,based on the actual needs,the path planning algorithm with certain constraints is designed.The constraints are prohibit a certain way and must pass through a certain point.At last,we apply the algorithm proposed in this paper to urban road network and compare it with traditional Dijkstra algorithm.The results show that,due to the searching area is restricted reasonably,the two algorithms get the same shortest path,but the time spent by the algorithm proposed in this paper is much less.Besides,the algorithm proposed in this paper can do well in path planning with constraints.Thus,the improved Dijkstra algorithm based on SuperMap GIS has a strong practicability,and can be used in real-time vehicle navigation.
  • Yali LI, Xiaoqin WANG, Yunzhi CHEN, Miaomiao WANG
    Journal of Geo-information Science. 2019, 21(3): 445-454. https://doi.org/10.12082/dqxxkx.2019.180316
    CSCD(6)

    Land surface temperature (LST) and fractional vegetation coverage (FVC) are important indicators of ecological environment changes. Studying the temporal and spatial variations of LST and FVC as well as their interaction in Fujian Province are of great significance to the evaluation of ecological environment construction and improvement of regional ecological environment. In this study, the temporal and spatial variations of LST in Fujian Province and the interaction between LST and FVC are analyzed, based on the reconstruction time series data of MODIS 11A2 LST and 13Q1 NDVI from 2001-2015. The results showed that: (1) The overall LST in Fujian Province presented a slight downward trend from 2001 to 2015, and the downward trend of LST is more pronounced after 2010. The spatial distribution of LST and FVC had a good negative correlation consistency, which implies the LST value is lower in the higher area while the LST is higher in the lower FVC area. (2) LST is negatively correlated with FVC, DEM and latitude. And their negative correlation was increased or decreased regularly with the change of months in a year .The negative correlation between FVC and LST was higher in summer and became lower in winter with the correlation coefficient reduced from 0.7 to 0.4. (3) The decreasing trend of LST with the increase of FVC is piecewise linear and has an obvious "FVC inflection point". In front and behind "FVC inflection point", the decreasing trends of LST with the increase of FVC are "slowly first and fast afterwards" in summer and "fast followed by slow "in winter. Moreover, the difference of LST decreasing rate with the increase of FVC becomes smaller in spring and autumn. In summer, when FVC is greater than 0.4, the LST can reduce about 0.77 °C with FVC value increase 0.1, and the cooling effect is about twice as much as that when FVC is less than 0.4. Therefore, if we want to effectively reduce LST in summer, we should make the surface vegetation cover more than 40%。Only in this way can vegetation play a better role in cooling. (4) From January to August, the negative correlation of FVC on LST has a lag, and vegetation change has a greater impact on the spatial and temporal distribution of the next month's LST. This study has a certain significance for the construction and evaluation of ecological environment in Fujian Province, and provide an important reference for the development of vegetation to suppress regional high temperature.

  • ARTICLES
    ZHANG Dongshui, LAN Zhangren, LI Zheng, ZHANG Wei
    . 2008, 10(1): 50-54.
    CSCD(1)
    The component-based GIS system has enormous advantages in seamless integration and the flexibility of the system.It stands for the development trend of GIS.Applying the ComGIS based technology,a specific GIS system for monitoring and management of the Minjiang River Estuary wetland based on MapObjects and Visual Basic has been developed in this research.The spatial visualization analysis of the wetlands' dynamic change,in turn,can be implemented.
  • Orginal Article
    SUN Zhen,JIA Shaofeng,LV Aifeng,ZHU Wenbin,GAO Yanchun
    Journal of Geo-information Science. 2016, 18(2): 227-237. https://doi.org/10.3724/SP.J.1047.2016.00227
    CSCD(1)

    This article estimated the precision of the precipitation simulated by 15 IPCC AR5 (the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, IPCC AR5) GCMs (Global Climate Models) and the multi-model ensemble (MME), based on the observed precipitation from 660 stations in China during 1996 to 2005. We firstly extracted the model simulation value at the corresponding position of the meteorological station, using the bilinear interpolation method, and took the average value of different models at the same station as the multi-model ensemble simulation value, then estimated the precision of the precipitation simulated by 15 IPCC AR5 GCMs and MME based on the observation of meteorological station. There were four evaluation parameters, including Corr (correlation coefficient), Bias, MRE (Mean Relative Error), and RMSE (Root Mean Square Error). Results show that the biases of the average daily precipitations simulated by IPCC AR5 GCMs present a gradually downward trend from northwest to southeast, and the RMSEs show a gradually increasing trend from northwest to southeast, while MREs in the east are less than those in the west. 82.3% of the average daily precipitations simulated by MRI-CGCM3 have relatively small biases, ranging from -0.5 to 0.5. The precisions of average daily precipitations simulated by BNU and MIROC-ESM are lower than that of others. Compared with other models, the MME simulation has the largest percentages of which the correlation coefficients are more than 0.5, MREs are less than 0.5, and RMSEs are less than 4mm, which accounted for 64.8%, 25.8% and 86.4% respectively. And the percentage of the biases ranging from -0.5 to 0.5 is relatively large, which is 56.7%, indicating that the simulation precision of MME is better than that of any other GCMs, and the MME can reduce the uncertainty of a single GCM simulation in future scenarios. Therefore, it is more scientific and reasonable to select the precipitation simulated by MME as the climate change condition, while studying subjects related to climate change.

  • ARTICLES
    CHEN Zi-Na
    . 1996, 0(2): 78-78.
    ‘八五’农作物遥感估产国家攻关项目的研究·解决了一批主要农作物遥感估产中的关键技术问题,如播种面积提取技术信息复合技术、遥感估产模型建立的技术和全数字化电脑估产技术等。
  • JIANG Ling,LING Dequan,ZHAO Mingwei,WANG Chun,ZENG Weibo
    Journal of Geo-information Science. 2018, 20(3): 281-290. https://doi.org/10.12082/dqxxkx.2018.170350
    CSCD(1)

    Terrain position is the basic morphologic feature on the surface of the Earth. The classification and extraction of terrain position have been widely applied in many research fields such as landform evolution, digital soil mapping and landscape ecological mapping. Proposed by Kang X et al. (2016), the multi-scale Geomorphons method maps terrain position by recognizing the morphology of each interest cell in a DEM according to its relative altitudes within the neighboring window. Multi-scale Geomorphons method can avoid the shortnesses of other classificaton methods, which are caused by different terrain attributes and a single analysis scale. However, there are still some drawbacks in the multi-scale Geomorphons method. For example, the classification results are fragmented and the domain of the analysis scale is difficult to determine. To solve the above problems, this paper presents a new method to classify terrain position, which is based on object-oriented segmentation and multi-scale Geomorphons. First of all, we propose an approach of determining the domain of optimal analysis scale of the multi-scale Geomorphons method. Then, the multi-scale segmentation and classification methods are constructed according to the initial terrain position data via the multi-scale Geomorphons method. At last, the presented method is evaluated by the experimental data of the DEM with 5 m resolution in the loess plateau region of northern Shaanxi. The experimental results show that: (1) the method of mean change-point analysis can effectively solve the problem which is difficult to determine the domain of the analysis scale of the multi-scale Geomorphons method. The domain of optimal analysis scale of the sample area is 5×5 to 33×33 cells. (2) The layer of each terrain position type with the value 0 for non-type cells and 255 for type cells is suitable for multi-scale segmentation. The parameters (i.e. scale, weight of shape and weight of compactness) for multi-scale segmentation have deep influence on segmentation results. There is optimal segmentation parameters for a experimental region. There is optimal segmentation parameter for an experimental region. (3) Comparing with the multi-scale Geomorphons method, the classification results of the present approach are more integrity and reasonable in the aspects of morphology correspondence and geological interpretation.

  • ARTICLES
    ZHANG Jin
    CSCD(4)

    The geosensor networks system of mine ground disaster monitoring is a integrating system implemented by comprehensive application of geomatics technology, that is, satellite remote sensing, geographic information systems, satellite positioning, Georobots, ground based SAR, and sensor networks. It is of great practical significance to predict the mine ground disasters timely and accurately, in order to prevent and reduce the loss of mine ground deformation disaster. The main research contents of the geosensor networks system of mine ground disaster monitoring include data whole processing theory and method, geographic grid and function partition, data fusion, spatial data clustering analysis, disaster effect analysis, intelligent forecasting models and theory, spatial database and service platform system. Using time-series monitoring data of multiphase geosensor networks, the high-resolution satellite remote sensing monitoring data and the function partition data, the dynamic deformation field can be established over mining region based on the research of spatiotemporal variations, so as to evaluate the effectiveness of the dynamic deformation field by measured data and optimize the deformation field model. Finally we can develop the geosensor networks GIS system of mine ground disasters monitoring and realize the integrating management of monitoring data and analyzing for the purpose of mine safety production and ground deformation monitoring and forecasting.

  • ARTICLES
    LIN Hui, ZHANG Jie, YANG Ping, LIU Jia
    . 2006, 8(2): 30-37.
    CSCD(7)
    Two basic dimensions for describing the human social development and human cultural phenomena are space and time. Previous humanities research emphasizes much of the attribution of phenomena itself and time dimension because of the technologic limitation and epistemological difference. Sometimes these research ignored the space dimension or retained the attitude of excluding it. Fortunately, more and more scholars have rethought the importance of spatial coordination system and begun to use spatial thinking in their research. These scholars come from the discipline of history, philosophy, literature, economics, sociology, anthropology, archeology, geography, politics, statistics, etc. This article, based on the instructive thought of space and integrated humanities and social science research, intends to take modern geographic information science and methodology and related space technology as a platform, to tentatively discuss the spatio -temporal characteristics of multi-disciplinary humanity and social science research. Emphases are given particularly to the spatial attribute, space distribution, spatially mutual affection and space evolution rule of the economic and cultural phenomena in human society. In this article, the authors put forward the elementary thought of spatially integrated humanities and social science research which includes basic concept, research object, basic methodology and development direction and wish it can promote the discussion.