Ecological risk assessment(ERA) is an indispensable method for systematic monitoring of World Heritage Sites(WHSs) exposed to various anthropogenic factors and natural disasters. Remote sensing(RS) and geographical in...Ecological risk assessment(ERA) is an indispensable method for systematic monitoring of World Heritage Sites(WHSs) exposed to various anthropogenic factors and natural disasters. Remote sensing(RS) and geographical information systems(GIS) can eliminate many limitations in traditional ERA methods. In this study, changes in ecological risk at Huangshan Mountain, the first mixed WHS in China, over the period of 1984–2019 were explored using remote sensing images and products by considering both natural disasters and human disturbance. Results show that of the four land cover types in Huangshan Mountain, namely water, forest, building and farmland, the main land cover type is forest. During the 35 yr, lands categorised at low or relatively low ecological risk levels are dominant in Huangshan Mountain, with the lowest and highest ERIs(ecological risk index) in 1990 and 2010, respectively. The areas at the five ecological risk levels have declined as follows: relatively low > low > medium > relatively high > high. Changes in ecological risks are closely related to changes in land cover and natural disasters. Even though major natural disasters may affect the ecological risk level in the whole region, changes in land cover caused by human activities will shift the ecological risk level in some areas. Our attempts can be modified and applied to other sites, and offer policy implications for protection and preservation of WHSs.展开更多
风景区的生态风险评价有助于指导其村镇建设、产业发展和实现绿色生态可持续发展.为探究峨眉山风景区生态风险分布和主要影响因素,在RS(Remote Sensing,遥感)和GIS(Geographic Information System,地理信息系统)技术支持下,以2015年土...风景区的生态风险评价有助于指导其村镇建设、产业发展和实现绿色生态可持续发展.为探究峨眉山风景区生态风险分布和主要影响因素,在RS(Remote Sensing,遥感)和GIS(Geographic Information System,地理信息系统)技术支持下,以2015年土地覆盖数据为基础,结合DEM、遥感影像数据,从自然灾害和人类干扰两方面分析生态风险,依据生态风险度量原理,通过计算风险发生概率和生态易损性求得生态风险值,利用克里金插值法求得峨眉山风景区生态风险空间分布.结果表明:①峨眉山风景区综合生态风险值较小,主要受自然灾害影响,其贡献率高达89.9%;人类干扰带来的影响也不可忽视,贡献率为10.1%.自然灾害中,干旱、地质灾害对风景区的影响较大,贡献率分别为40.9%、49.3%.②峨眉山风景区综合生态风险呈条带状分布,越往东综合生态风险值越大,自然灾害风险空间分布与其基本一致.综合生态风险高风险区聚集在万年寺、清音阁、神水阁景区,景区东部黄湾乡旅游镇属于人文风险高风险区.研究显示,峨眉山风景区综合生态风险主要受到自然灾害影响,存在带状分异的空间规律.展开更多
In this paper,the technique of quasi_lossless compression based on the image restoration is presented.The technique of compression described in the paper includes three steps,namely bit compression,correlation removin...In this paper,the technique of quasi_lossless compression based on the image restoration is presented.The technique of compression described in the paper includes three steps,namely bit compression,correlation removing and image restoration based on the theory of modulation transfer function (MTF).The quasi_lossless compression comes to a high speed.The quality of the reconstruction image under restoration is up to par of the quasi_lossless with higher compression ratio.The experiments of the TM and SPOT images show that the technique is reasonable and applicable.展开更多
This paper discusses methods for character extraction on the basis of statistical and structural features of gray_level images,and proposes a dynamic local contrast threshold method accommodating to line width.Precise...This paper discusses methods for character extraction on the basis of statistical and structural features of gray_level images,and proposes a dynamic local contrast threshold method accommodating to line width.Precise locating of character string is realized by exploiting horizontal projection and character arrangements of binary images in horizontal and vertical directions respectively.Also discussed is the method for segmentation of characters in binary images,which is based on projection taking stroke width and character sizes into account.A new method for character identification is explored,which is based on compound neural networks.A complex neural network consists of two sub_nets,the first sub_net performs self_association of patterns via 2_dimentional local_connected 3_order networks,the second sub_net,linking with a locally connected BP networks,performs classification.The reliability of the network recognition is reinforced by introducing conditions for identification denial.Experiments confirm that the proposed methods possess the advantages of impressive robustness,rapid processing and high accuracy of identification.展开更多
There is a trend for rapid spatial data capture supported by integration of multiple platforms and multiple sensors.This paper presents the principles and technologies of land-based mobile mapping systems based on an ...There is a trend for rapid spatial data capture supported by integration of multiple platforms and multiple sensors.This paper presents the principles and technologies of land-based mobile mapping systems based on an integration of remote sensing,GPS and GIS technologies.The innovations and advantages of the integrated system are described.The analytic model and error model of a mobile mapping system are proposed and the application interface of digital measurable images is also discussed.A Truemap Engine? with Plug-in and API is designed to manage a huge volume of stereo image series from a land-based mobile mapping system so that other geographic information systems(GIS) engines can freely use the sequence of stereo images.The applications of digital measurable images(DMI) as well as mobile mapping systems in the Olympic Games in Beijing,2008 are presented.展开更多
基金Under the auspices of the National Key Research and Development Program of China (No. 2020YFC1521903)National Key Research and Development Program of China (No. 2018YFD1100104)。
文摘Ecological risk assessment(ERA) is an indispensable method for systematic monitoring of World Heritage Sites(WHSs) exposed to various anthropogenic factors and natural disasters. Remote sensing(RS) and geographical information systems(GIS) can eliminate many limitations in traditional ERA methods. In this study, changes in ecological risk at Huangshan Mountain, the first mixed WHS in China, over the period of 1984–2019 were explored using remote sensing images and products by considering both natural disasters and human disturbance. Results show that of the four land cover types in Huangshan Mountain, namely water, forest, building and farmland, the main land cover type is forest. During the 35 yr, lands categorised at low or relatively low ecological risk levels are dominant in Huangshan Mountain, with the lowest and highest ERIs(ecological risk index) in 1990 and 2010, respectively. The areas at the five ecological risk levels have declined as follows: relatively low > low > medium > relatively high > high. Changes in ecological risks are closely related to changes in land cover and natural disasters. Even though major natural disasters may affect the ecological risk level in the whole region, changes in land cover caused by human activities will shift the ecological risk level in some areas. Our attempts can be modified and applied to other sites, and offer policy implications for protection and preservation of WHSs.
文摘风景区的生态风险评价有助于指导其村镇建设、产业发展和实现绿色生态可持续发展.为探究峨眉山风景区生态风险分布和主要影响因素,在RS(Remote Sensing,遥感)和GIS(Geographic Information System,地理信息系统)技术支持下,以2015年土地覆盖数据为基础,结合DEM、遥感影像数据,从自然灾害和人类干扰两方面分析生态风险,依据生态风险度量原理,通过计算风险发生概率和生态易损性求得生态风险值,利用克里金插值法求得峨眉山风景区生态风险空间分布.结果表明:①峨眉山风景区综合生态风险值较小,主要受自然灾害影响,其贡献率高达89.9%;人类干扰带来的影响也不可忽视,贡献率为10.1%.自然灾害中,干旱、地质灾害对风景区的影响较大,贡献率分别为40.9%、49.3%.②峨眉山风景区综合生态风险呈条带状分布,越往东综合生态风险值越大,自然灾害风险空间分布与其基本一致.综合生态风险高风险区聚集在万年寺、清音阁、神水阁景区,景区东部黄湾乡旅游镇属于人文风险高风险区.研究显示,峨眉山风景区综合生态风险主要受到自然灾害影响,存在带状分异的空间规律.
文摘In this paper,the technique of quasi_lossless compression based on the image restoration is presented.The technique of compression described in the paper includes three steps,namely bit compression,correlation removing and image restoration based on the theory of modulation transfer function (MTF).The quasi_lossless compression comes to a high speed.The quality of the reconstruction image under restoration is up to par of the quasi_lossless with higher compression ratio.The experiments of the TM and SPOT images show that the technique is reasonable and applicable.
文摘This paper discusses methods for character extraction on the basis of statistical and structural features of gray_level images,and proposes a dynamic local contrast threshold method accommodating to line width.Precise locating of character string is realized by exploiting horizontal projection and character arrangements of binary images in horizontal and vertical directions respectively.Also discussed is the method for segmentation of characters in binary images,which is based on projection taking stroke width and character sizes into account.A new method for character identification is explored,which is based on compound neural networks.A complex neural network consists of two sub_nets,the first sub_net performs self_association of patterns via 2_dimentional local_connected 3_order networks,the second sub_net,linking with a locally connected BP networks,performs classification.The reliability of the network recognition is reinforced by introducing conditions for identification denial.Experiments confirm that the proposed methods possess the advantages of impressive robustness,rapid processing and high accuracy of identification.
基金Supported by the National Natural Science Foundation of China (Grant No.49631050)the Major State Basic Research Development Program of China (Grant No.2006CB701302)
文摘There is a trend for rapid spatial data capture supported by integration of multiple platforms and multiple sensors.This paper presents the principles and technologies of land-based mobile mapping systems based on an integration of remote sensing,GPS and GIS technologies.The innovations and advantages of the integrated system are described.The analytic model and error model of a mobile mapping system are proposed and the application interface of digital measurable images is also discussed.A Truemap Engine? with Plug-in and API is designed to manage a huge volume of stereo image series from a land-based mobile mapping system so that other geographic information systems(GIS) engines can freely use the sequence of stereo images.The applications of digital measurable images(DMI) as well as mobile mapping systems in the Olympic Games in Beijing,2008 are presented.
