8 resultados para geographical information systems (GIS)
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
本文利用地理信息系统(GIS)技术、景观生态学理论和方法、分形理论以及统计分析方法对北京地区植被景观的空间分布特征进行了分析,并对景观格局和景观多样性的分析方法进行了探讨,结果表明: (1)对几乎所有的斑块类型,其斑块大小的分布都不是对称的,而是右偏的。4种概率分布(Г—分布、对数正态分布、Weibull分布和(负)指数分布)都只能刻划部分斑块类型,并且服从对数正态分布的斑块类型最多,服从(负)指数分布的斑块类型最少。 (2)随着斑块面积的增加,边界效应越来越小,而斑块形状越来越不紧凑。 (3)分形分析识别出本地区植被景观中的两个尺度域:一个是斑块面积小于(大约)2.7km2,另一个是斑块面积大于(大约)2.7km2。两个域中的斑块复杂程度有很大差异,后一个域中的斑块明显比前一个域中的斑块复杂,并且随着斑块面积的增加,斑块形状越来越复杂。 (4)用斑块数作为多度指标时,该景观的斑块类型一多度分布服从(截断)对数正态分布和(截断)负二项分布,不服从对数级数分布和几何分布。用斑块面积作为多度指标时,该景观的斑块类型一多度分布服从对数正态分布、Weibull分布和Г—争布,不服从正态分布。从而该景观的斑块类型一多度分布不是对称的,也是右偏的。在4个优势度/多样性模型中,“生态位优先占领”模型和Zipf-Mandelbrot模型可以较好地刻划该景观的斑块类型一多度关系。 (5)样本大小对多样性测度有直接的影响。如果这种影响比较小,就说明测度指标比较稳定。三个丰富度指数中,Ri比R2和R3更稳定;五个多样性性指数中,D和Di最稳定,OD最不稳定,因此,OD是用于景观多样性监测的理想指标;五个均匀度指数中,Jgi最稳定。根据设计的3种计算临界样方数量(即多样性测度指标达到稳定时的样方数量)方法的计算结果,上述几个最稳定的测度指标在通常情况下只需要几个样方(即总抽样面积为数百km2)就达到稳定状态。 (6)斑块类型数目随面积的增加而增加。根据四个评价指标的评价结果,认为双曲线对该景观的斑块类型一面积关系的拟合效果最好。 (7)样本较大(对于一阶刀切估计,大于30个样方;对于二阶刀切估计,大于60个样方)时,刀切法能够给出斑块类型数目(NPT)较好的估计;样本较小(小于30个样方)时,Mingoti和Meeden提出的经验贝叶斯方法能够对NPT给出比刀切法和自助法更好的估计。斑块类型一面积曲线外推虽然也能给出NPT较好的估计,但这种方法需要慎重使用,不能外推得很远。 (8)列联表分析表明,该植被景观中的斑块类型与土壤类型、岩石类型、海拔高度和坡向各因子之间均存在显著的相关性。植被景观多样性与岩石类型多样性和地形多样性之间也均呈显著的正相关关系,即植被景观多样性随岩石类型多样性和地形多样性的增加而增加。但植被景观多样性与土壤类型多样性之间不存在显著的线性相关或秩相关关系,这可能是由于二者的分类体系不吻合。植被景观多样性与总的道路密度和第二类道路密度之间均呈显著的负相关关系,而与第一类和第三类道路密度之间的关系都不显著。这反映出景观样本单元(10kmxlOkm)的尺度对应于第二类道路的影响尺度。而道路密度在一定程度上反映了人类活动的强度,因此,在10kmxlOkm这个尺度上,人类活动愈剧烈,景观多样性就愈小。
Resumo:
China is experiencing a rapid development of highway ever since 1990s. By the end of 2004, the total length of the highway summed up to 33 thousand kilometers, ranking 2n in the world. After the open of highway, the accumulation of time and traffic causes the decrease of its capability. To ensure its good quality, security and operation functions, we should take some reasonable measures to maintain it periodically. At present, a big problem is that the traditional maintain measures can no longer meet the increasing requirements. Due to the characters of highway, the relationship of various maintenance data and geographic positions is even closer than any others. If we wan to improve the quality and efficiency of the maintenance work, particularly when there is need for decision-making, a great number of data that is related to geographic positions are absolutely necessary. Evidently, Geographical Information System (GIS) has incomparably advantages in dealing with these spatial information. As a result, a management system for highway maintenance work based on GIS became inevitable for the development of the maintenance of highway. The purpose of this paper is to establish a management system for highway maintenance work base on Geographical Information System (GIS), Global Positioning System (GPS) and spatial database, to manage all kinds of problems encountered in the work, and to provide support on information and methods. My study mainly includes: (1) Analysis on the current status of the maintenance and management work; overview on the history of domestic and international highway maintenance management systems; identifying the necessity and importance for establishing a management system for highway maintenance work based on GIS. (2) Based on the requirement analysis, I proposed a general design for this management system, and discussed the objective, design principles, framework, systematical structure and function design. (3) Outdoor data collection is not only a prime way to understand the current situation of the road, but also an important method for data update after the system is put into use. This paper also intends to establish a set of plan to collect data efficiently and precisely which is based on GIS and GPS technologies. (4) The maintenance management database is a supporting platform for various maintenance decision-makings. Such decisions need the support of a great amount of data, which would cause other problems, such as the diversity of the data source, difference of data formats. This paper also discussed how to deal with these problems and establish such a database. (5) To propose an approach to assess the condition of pavement, based on GIS and related maintenance models. Among all the maintenance models, the two for assessing and forecasting pavement condition are the most important and mature. This paper also analyzed these two models and introduced them in terms of the integration of models. (6) This paper took the Guangshen Highway for example, explaining how to realize a GIS for management of highway maintenance work.
Resumo:
根据1997年、2001年和2005年三期TM影像资料,运用遥感非监督分类的方法提取土地利用信息。利用地理信息系统空间分析和数据统计的方法,分析藉河流域1997~2005年间土地利用数量变化和空间变化特征,研究该地区主要土地利用类型数量变化、空间变化以及在不同坡度的动态变化特征。结果表明:耕地、林地和草地三种主要土地利用类型占该研究区土地利用面积的97%以上,是该研究区主要的土地利用类型。以1997年为基数,到2001年和2005年耕地减少幅度分别为1.2%和11.1%,因此1997~2001年的退耕程度小于2001~2005年;在不同坡度上,土地利用变化主要发生在5°~40°,而且在15°~25°之间变化最大。
Resumo:
揭示水体中繁殖的两栖动物在异质性景观中的空间扩散特点,探讨景观面积丧失和破碎化对于两栖动物的影响,为两栖动物的保护提供理论依据。本文以四川西北部若尔盖湿地自然保护区的高原林蛙(Rana kukunoris)为研究对象,通过运用地理信息系统及建立景观模型等方法,在分析若尔盖湿地自然保护区范围内现有景观格局的基础上,建立了高原林蛙的景观扩散模型,并模拟了“沼泽→草甸”的湿地逆演化过程下高原林蛙的空间分布与景观连接的变化特点。主要结果是: 1.若尔盖湿地自然保护区呈典型的沼泽—草甸式斑块—基质景观格局。草甸面积占整个景观面积的79.42%,景观蔓延度指数(CONTAG)为79.00远离最小值0而更趋向于最大值100,面积和景观蔓延度指数表明草甸是整个景观中面积占绝对优势且景观连接好的类型,构成了景观的基质,对景观的动态格局演变起主导作用。沼泽面积仅占整个景观面积的18.08%,但却是整个景观中斑块数目最多的单元,占所有斑块数的82.9%。因此沼泽斑块与草甸基质之间的动态结构对高原林蛙的扩散起着决定性的作用。 2.空间扩散模型表明,其它类型的景观不但扩展了高原林蛙的活动范围,而且也为高原林蛙在不同沼泽斑块间的连接提供了通道。高原林蛙的空间扩散区域使得彼此间成斑块化隔离状分布的沼泽形成了潜在景观功能连接,促进了不同斑块间物种的交流。小型沼泽作为垫脚石(stepping-stone),使得整个景观中的相隔距离较远的大型斑块联结为一个功能整体,促进了高原林蛙在整个景观中的相互动态联系。 3.模拟“沼泽→草甸”的湿地逆演化过程表明,大量小型沼泽湿地的消失将会 对在沼泽中繁殖并扩散到其它景观类型中去的高原林蛙造成潜在影响。逆演化过程不仅使沼泽斑块的分布范围,沼泽源斑块的面积和空间扩散面积减少,而且对景观连接也有很大影响。小型沼泽的消失,将使得景观斑块的功能连接变小,使得依靠小型沼泽作为跳板的动物在沼泽斑块之间的移动将变得更加困难。 本文是对生境丧失与破碎化影响下两栖动物的行为反应的一种尝试。影响模型的因素很多,包括动物对各种类型景观的偏好程度,地理数据的精度,及模型的可靠程度都是制约模型准确度的因素。 The spatial diffusion of water—breeding amphibian through heterogeneous landscape and the effects of landscape losing and fragmentation to amphibian were the core theory of the landscape ecology of amphibian. Geographical information system (GIS) and landscape model were used to model the diffused area of Rana kukunoris in Zoige Wetland Natural Reserve. Model was also used to analysis the spatial distribution variation of R. kukunoris and the change of landscape connectivity when simulated the retrogressive succession of landscape. The main results are below: 1. There was peatland—meadow pattern which was typical patch—matrix landscape pattern in Zoige Natural Reserve. The meadow area occupied 79.42% of the entire landscape area, contagion index (CONTAG) was 79.00 which was far away the minimum value (0) but tend to the maximum value (100). Both of these showed that meadow was the largest part and the most continue units. It was shown that meadow was matrix of the landscape, which evolved the leading role to the landscape dynamic pattern. Though their area only occupies 18.08% of entire landscape area, peatlands were according to 82.9% of the total patches. Dynamic of the pattern between peatlands and meadows decided the spatial diffusion of R. kukunoris. 2.The model indicated that the other types of landscape not only expanded diffusion of R. kukunoris, but also have provided the potential channels for frog's connections among different peatlands. The spatial diffusion zone of R. kukunoris forced isolated patch peatlands to be potential landscape functional connectivity. The small peatlands, as stepping-stone, made the large peatlands connect as a functional one and promoted the integrated and dynamic connectivity of R. kukunoris in the whole landscape. 3. The simulation of “peatlands→meadows”retrogressive succession process indicated that the decrease of small peatlands will have potential effect to R. kukunoris because they must bred in peatlands and diffuse to other type of the landscape. Retrogressive succession process not only made the decrease of distribution of peatlands, patches number of peatlands and diffused area of R. kukunoris, but also reduced the connectivity among source patches. As stepping-stone, the disappearance of small peatlands will made the migration of R. kukunoris among patches more difficult. The model was an experiment of the amphibian behavior reaction to habitat losing and fragmentation. There were many factors that could influence the accuracy of model, such as the preference of animals to each type of landscape, the geographical data precision, reliable degree of model.
Resumo:
It has been 10 years since the publication of the relative risk model (RRM) for regional scale ecological risk assessment. The approach has since been used successfully for a variety of freshwater, marine, and terrestrial environments in North America, South America, and Australia. During this period the types of stressors have been expanded to include more than contaminants. Invasive species, habitat loss, stream alteration and blockage, temperature, change in land use, and climate have been incorporated into the assessments. Major developments in the RRM have included the extensive use of geographical information systems, uncertainty analysis using Monte Carlo techniques, and its application to retrospective assessments to determine causation. The future uses of the RRM include assessments for forestry and conservation management, an increasing use in invasive species evaluation, and in sustainability. Developments in risk communication, the use of Bayesian approaches, and in uncertainty analyses are on the horizon.