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71.
Automatic 3D extraction of building roofs from remotely sensed data is important for many applications including city modelling. This paper proposes a new method for automatic 3D roof extraction through an effective integration of LIDAR (Light Detection And Ranging) data and multispectral orthoimagery. Using the ground height from a DEM (Digital Elevation Model), the raw LIDAR points are separated into two groups. The first group contains the ground points that are exploited to constitute a ‘ground mask’. The second group contains the non-ground points which are segmented using an innovative image line guided segmentation technique to extract the roof planes. The image lines are extracted from the grey-scale version of the orthoimage and then classified into several classes such as ‘ground’, ‘tree’, ‘roof edge’ and ‘roof ridge’ using the ground mask and colour and texture information from the orthoimagery. During segmentation of the non-ground LIDAR points, the lines from the latter two classes are used as baselines to locate the nearby LIDAR points of the neighbouring planes. For each plane a robust seed region is thereby defined using the nearby non-ground LIDAR points of a baseline and this region is iteratively grown to extract the complete roof plane. Finally, a newly proposed rule-based procedure is applied to remove planes constructed on trees. Experimental results show that the proposed method can successfully remove vegetation and so offers high extraction rates. 相似文献
72.
Agro-biodiversity in the desert oases of the Baja California peninsula, Mexico is a product of isolation and integration events through time and across peninsular spaces. Historic inventories of agricultural introductions provide a baseline from which to measure Mission-era crop persistence or genetic erosion in fifteen missions established during the Jesuit occupation (1697–1768). These mission-oases function as a network of interconnected sites supporting cultivated plant assemblages isolated from one another and the Mexican mainland by a desert matrix, by limited transportation infrastructure on the peninsula, and the surrounding sea. Garden surveys of perennial crop species and farmer interviews reveal that oases serve as refugia of Mission-era crop species and traditional knowledge. Isolation-connectivity analyses indicate that this agro-biodiversity disappears at the extremes: The most isolated and the fully integrated oases are unable to support heritage perennial crop species and traditional farming systems over long time scales. We describe how phases and processes of isolation and connectivity transform agro-biodiversity composition in this archipelago of peninsula oases and explore policy applications that could preserve this critical diversity and the rare and available oasis communities. 相似文献
73.
Integration degree of risk in terms of scene and application 总被引:2,自引:2,他引:0
Chongfu Huang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(4):473-484
Risk is a scene in the future associated with some adverse incident. Scene means something seen by a viewer, or felt by individuals
or various societal groups. Any risk assessment is to model some aspects of the scene for risk. Different aspects for assessment
leads to different scene. In this paper, we suggest the integration degree of risk to distinguish characters of risks with
respect to the aspects. The total number of factors of a risk system determines the macro degree and the granulation scale
for measuring a risk reflects the micro degree. A simple framework depends on the degrees provides an explanation of the integrated
risk. The most common model for risk assessment is available for the two-freedom-degree serial risk. A case studying flood
risk shows the application to explain what the risk is, where the information is incomplete and we use the information diffusion
technique to estimate the risk.
Project 40771007 supported by National Natural Science Foundation of China. 相似文献
74.
75.
GIS在青岛海域管理中的应用 总被引:4,自引:1,他引:3
奥勇 《地球科学与环境学报》2004,26(2):71-74
阐述了基于GIS(地理信息系统)技术,对青岛海域使用管理系统进行设计与集成二次开发方法,通过MapX二次开发工具,实现了系统的主要功能,以直观的图面表示海域和相邻陆域海洋功能区类型,揭示了各区域的主导功能,突出了海洋功能特点,丰富了图件的信息量。 相似文献
76.
“3S技术”集成在地震灾害调查与研究中的应用初探 总被引:5,自引:0,他引:5
遥感(RS)、全球定位系统(GPS)和地理信息系统(GIS)技术在自身进一步发展的同时,正日益朝集成化方向迈进,形成所谓“3S技术”集成。“3S技术”集成,为地震灾害调查和研究提供了新的、极具潜力的技术支持。本文简要分析了“3S技术”在震害调查与研究中的应用现状,并着重从“3S技术”集成的角度,探讨它在未来震害调查与研究中的应用模式及实施方案问题。 相似文献
77.
78.
电阻率层析成像方法技术近年发展概况 总被引:15,自引:7,他引:8
本文对近年来电阻率层析成像在方法技术方面的进展作了简要介绍,并对几种具有代表性的方法,表述了它们各自的优缺点,提出了继续研究的方向。 相似文献
79.
This article presents a general introduction to the development in China since 1980s in precision seafloor survey and mapping. Emphasis is given to the processing and integration of data from the acquisition system centered on the multibeam bathymetric survey equipment, and to the interactive map generation systems, MBChart, SeaMap, and SeaGIIS. Application of these systems will also be described. 相似文献
80.
This paper presents an account of the progress of the integration between the Danish and Swedish parts of the Öresund Region within the world of science, with emphasis on biotech. The paper is based on data from the database Science Citation Index Expanded. The amount of co-authorships produced by agents from each side of the region is analysed for a 12-year period (1994–2005) and used as an indicator to show how the integration is proceeding. Each of the co-authorships is examined to shed light on the nature of the interactions, thereby identifying the agents most involved in collaboration. Furthermore, the development in co-authorships within the region is compared to the development in co-authorships between the Öresund Region and four selected reference areas. Our findings indicate that there has been a substantial increase in both the number of co-authorships overall and within biotech solely. The rise in co-authorships between the two parts is proceeding at a faster pace than the rise in co-authorships between the Öresund Region and the reference areas. The overall results of this paper indicate a growing integration of the biotech sector in the Öresund Region. 相似文献