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1.
Biogeographers have developed a new generation of statistical models called presence-only models, which require no data concerning the absence of a species and do not assume that the absence of a species indicates habitat unsuitability. Both characteristics are especially useful when modeling a species that is actively spreading across a landscape. Although urban expansion is sometimes equated to an invading species, the applicability of presence-only models has not yet been explored when modeling urban growth. This article compares predictions of urban growth using a presence-only model (ecological niche factor analysis) and a more traditional presence–absence model (logistic regression). An additional model used pseudo-absence sites, from the presence-only model output, as input into the presence–absence model. The models were applied to New Jersey's Barnegat Bay Watershed. Overall, the traditional presence–absence model performed the best, although the presence-only model was sufficiently similar to warrant further exploration of presence-only models when no reliable absence data (i.e., locations where no conversion occurred) exists. However, due to data-formatting requirements of the presence-only model, it is difficult to accommodate data pertaining to administrative boundaries, which are inherently Boolean. Finally, the output based on the pseudo-absence approach overpredicted urban conversion when compared to the other approaches.  相似文献   

2.
An agent-integrated irregular automata model of urban land-use dynamics   总被引：2，自引：0，他引：2  
Urban growth models are useful tools to understand the patterns and processes of urbanization. In recent years, the bottom-up approach of geo-computation, such as cellular automata and agent-based modeling, is commonly used to simulate urban land-use dynamics. This study has developed an integrated model of urban growth called agent-integrated irregular automata (AIIA) by using vector geographic information system environment (i.e. both the data model and operations). The model was tested for the city of San Marcos, Texas to simulate two scenarios of urban growth. Specifically, the study aimed to answer whether incorporating commercial, industrial and institutional agents in the model and using social theories (e.g. utility functions) improves the conventional urban growth modeling. By validating against empirical land-use data, the results suggest that a holistic framework such as AIIA performs better than the existing irregular-automata-based urban growth modeling.  相似文献   

3.
Urbanization is an important issue concerning diverse scientific and policy communities. Computational models quantifying locations and quantities of urban growth offer numerous environmental and socioeconomic benefits. Traditional urban growth models are based on a single-algorithm fitting procedure and thus restricted on their ability to capture spatial heterogeneity. Accordingly, a GIS-based modeling framework titled multi-network urbanization (MuNU) model is developed that integrates multiple neural networks. The MuNU model enables a filtering approach where input data patterns are automatically reallocated into appropriate neural networks with targeted accuracies. We hypothesize that observations classified by individual neural networks share greater homogeneity, and thus modeling accuracy will increase with the integration of multiple targeted algorithms. Land use and land cover data sets of two time snapshots (1977 and 1997) covering the Denver Metropolitan Area are used for model training and validation. Compared to a single-step algorithm – either a stepwise logistic regression or a single neural network – several improvements are evident in the visual output of the MuNU model. Statistical validations further quantify the superiority of the MuNU model and support our hypothesis of effective incorporation of spatial heterogeneity.  相似文献   

4.
从内容、空间尺度、时间维、综合程度、建模方式、复杂程度和数学方法等方面对目前的城市模型进行了系统的分类。论述了城市模型研究的发展趋势：模型研究内容日益丰富和多元化;从静态模拟到动态模拟发展;从子系统模拟向综合系统模拟发展;遥感和GIS的应用以及与城市模型的集成。对城市模型研究的未来发展进行了展望,认为未来的城市模型开发应基于综合方法的思想,注重加强城市基本理论和多学科交叉研究,强调城市模拟的动态性和综合性。充分借助遥感与GIS等技术手段进行研究。  相似文献   

5.
ABSTRACT

Cellular automata (CA) are effective tools for simulating urban dynamics. Coupling top-down and bottom-up CA models are often used to address macro-scale demand and micro-scale allocation in the simulation of urban dynamics. However, those models typically ignore spatial differences in terms of the coupling process between macro-scale demand and micro-scale allocation. Herein, a novel approach for combining top-down and bottom-up strategies based on simulating urban dynamics is proposed. An optimizing strategy was used to predict the parameter of the inverse S-shaped function of future urban land use pattern and further deduce urban land increment within each concentric ring. The maximum probability transformation rule was incorporated into the CA model to address the micro-scale allocation. Wuhan was selected to test the performance of the proposed approach, and the conventional and the proposed approaches were compared. The results demonstrated that the proposed approach can not only retain the model’s accuracies but also better simulate the macro morphology of urban development dynamics and generate more realistic urban dynamic pattern in the urban sub-center and fringe regions. The proposed coupling approach can also be used to generate different development scenarios. The approach is expected to provide new perspectives for coupling top-down and bottom-up CA models in modeling urban expansion.  相似文献   

6.
Hybrid terrains are a convenient approach for the representation of digital terrain models, integrating heterogeneous data from different sources. In this article, we present a general, efficient scheme for achieving interactive level-of-detail rendering of hybrid terrain models, without the need for a costly preprocessing or resampling of the original data. The presented method works with hybrid digital terrains combining regular grid data and local high-resolution triangulated irregular networks. Since grid and triangulated irregular network data may belong to different datasets, a straightforward combination of both geometries would lead to meshes with holes and overlapping triangles. Our method generates a single multiresolution model integrating the different parts in a coherent way, by performing an adaptive tessellation of the region between their boundaries. Hence, our solution is one of the few existing approaches for integrating different multiresolution algorithms within the same terrain model, achieving a simple interactive rendering of complex hybrid terrains.  相似文献   

7.
The paper presents a computationally efficient meta-modeling approach to spatially explicit uncertainty and sensitivity analysis in a cellular automata (CA) urban growth and land-use simulation model. The uncertainty and sensitivity of the model parameters are approximated using a meta-modeling method called polynomial chaos expansion (PCE). The parameter uncertainty and sensitivity measures obtained with PCE are compared with traditional Monte Carlo simulation results. The meta-modeling approach was found to reduce the number of model simulations necessary to arrive at stable sensitivity estimates. The quality of the results is comparable to the full-order modeling approach, which is computationally costly. The study shows that the meta-modeling approach can significantly reduce the computational effort of carrying out spatially explicit uncertainty and sensitivity analysis in the application of spatio-temporal models.  相似文献   

8.
基于细胞自动机与多主体系统理论的城市模拟原型模型   总被引：5，自引：5，他引：0  
刘妙龙  陈鹏 《地理科学》2006,26(3):292-298
文章从城市地理学模拟模型研究发展相对滞后的现实出发,分析了传统城市模型模拟存在的问题与不足,讨论了计算机科学、复杂性研究、地理信息科学与技术、新发展的地学计算方法等作为计算城市模型发展基础的可行性,提出了一个基于细胞自动机与多主体系统理论与方法、包容了多尺度(宏观、中观、微观)层次的综合可计算城市模拟原型模型框架,对以邻里社区为基础的居住区位微观模拟模型作了概念上的讨论,分析了地学计算方法在城市模拟模型研究中的发展前沿。  相似文献   

9.
基于垄断竞争的大都市商业空间结构动态模拟   总被引：2，自引：1，他引：1  
薛领  翁瑾 《地理学报》2010,65(8):938-948
本文构建了一个基于垄断竞争、规模经济、交通成本、消费者多样化偏好以及商品和服务差异化的大都市两区域商业空间结构模型。提出了经济学演绎模型与基于agent 的计算实验相结合的研究路径,通过对商家、消费者等大量微观自主体(agent) 的相互作用来“动态地”观察和讨论大都市新、老城区宏观商业空间结构的微观基础、影响因素和演化过程。研究结果表明,①在商品和服务替代性、购物交通成本设定的情形下,新、老城区商业固定成本投入差距越大,则商业空间分布越不均衡,越易形成核心-边缘结构。② 由于居民的消费存在多样化偏好,因此强化区域间的差异性有助于改变商业的市场份额。③ 商业往往集聚在具有区位优势、人口规模优势以及固定成本优势的地区,而且交通条件的改善将加速商业的空间集聚。研究认为,空间经济学演绎模型与推导→基于agent 的地理计算→实证分析与计量检验是一个值得探索的技术路线。  相似文献   

10.
Land change science has become an interdisciplinary research direction for understanding human-natural coupling systems. As a process-oriented modelling approach, agent based model(ABM) plays an important role in revealing the driving forces of land change and understanding the process of land change. This paper starts from three aspects: The theory, application and modeling framework of ABM. First, we summarize the theoretical basis of ABM and introduce some related concepts. Then we expound the application and development of ABM in both urban land systems and agricultural land systems, and further introduce the case study of a model on Grain for Green Program in Hengduan Mountainous region, China. On the basis of combing the ABM modeling protocol, we propose the land system ABM modeling framework and process from the perspective of agents. In terms of urban land use, ABM research initially focused on the study of urban expansion based on landscape, then expanded to issues like urban residential separation, planning and zoning, ecological functions, etc. In terms of agricultural land use, ABM application presents more diverse and individualized features. Research topics include farmers' behavior, farmers' decision-making, planting systems, agricultural policy, etc. Compared to traditional models, ABM is more complex and difficult to generalize beyond specific context since it relies on local knowledge and data. However, due to its unique bottom-up model structure, ABM has an indispensable role in exploring the driving forces of land change and also the impact of human behavior on the environment.  相似文献   

11.
Urban growth and population growth are used in numerous models to determine their potential impacts on both the natural and the socio-economic systems. Cellular automata (CA) land-use models became popular for urban growth modelling since they predict spatial interactions between different land uses in an explicit and straightforward manner. A common deficiency of land-use models is that they only deal with abstract categories, while in reality, several activities are often hosted at one location (e.g. population, employment, agricultural yield, nature…). Recently, a multiple activity-based variable grid CA model was proposed to represent several urban activities (population and economic activities) within single model cells. The distance-decay influence rules of the model included both short- and long-distance interactions, but all distances between cells were simply Euclidean distances. The geometry of the real transportation system, as well as its interrelations with the evolving activities, were therefore not taken into account. To improve this particular model, we make the influence rules functions of time travelled on the transportation system. Specifically, the new algorithm computes and stores all travel times needed for the variable grid CA. This approach provides fast run times, and it has a higher resolution and more easily modified parameters than the alternative approach of coupling the activity-based CA model to an external transportation model. This paper presents results from one Euclidean scenario and four different transport network scenarios to show the effects on land-use and activity change in an application to Belgium. The approach can add value to urban scenario analysis and the development of transport- and activity-related spatial indicators, and constitutes a general improvement of the activity-based CA model.  相似文献   

12.
土地系统多主体模型的理论与应用   总被引：1，自引：0，他引：1  
戴尔阜  马良  杨微石  王亚慧  尹乐  童苗 《地理学报》2019,74(11):2260-2272
土地变化科学是理解人类—自然耦合系统的交叉学科研究方向。多主体模型（ABM）作为过程导向模型,对揭示土地变化驱动力,理解土地变化过程有重要作用。本文从理论、应用与建模框架三方面出发,总结了ABM理论基础和相关概念;阐述了ABM在城市和农业土地系统两方面的应用与发展,进一步介绍了横断山区退耕还林ABM研究案例;在梳理ABM建模协议的基础上,提出了主体视角的土地系统ABM建模框架和实施流程。在城市土地利用方面,ABM研究从最初基于景观研究城市扩张,到研究城市内部居住分隔,规划分区,生态功能等多方面;在农业土地利用方面,ABM应用则呈现出更加多样化和个性化的特征,包括农民行为、农户决策、种植系统、农业政策等。相比于传统模型,ABM因其依靠本地知识与数据而使得其构建更为复杂,且不易推广;但因其独特的自下而上模型构架,在探究土地变化驱动力、刻画人类行为对自然环境影响等方面具有不可或缺的作用。  相似文献   

13.
精准刻画城市住宅地价分布特征,对于科学引导城市空间布局规划、有效实现城市精明增长等具有重要意义。而城市住宅地价与其潜在影响因素之间的复杂非线性关系,给地价分布精细模拟带来了挑战。论文旨在探索基于地理大数据和集成学习的城市住宅地价分布模拟方法体系,以满足快速、精准监测地价动态变化的需要。选取武汉市为典型区,以住宅用地交易样点、兴趣点(points of interest, POI)和夜间灯光影像为数据源,以500 m分辨率网格为估价单元,提取POI核密度和夜间灯光强度作为住宅地价预测变量,采用机器学习算法和bagging、stacking集成方法构建住宅地价预测模型,并对比分析其精度。研究发现：① 单个机器学习算法中,支持向量回归(support vector regression, SVR)预测精度最高,接下来依次是k最近邻算法(k-nearest neighbor algorithm, k-NN)、高斯过程回归(Gaussian process regression, GPR)和BP神经网络(back propagation neural networks, BP-NN);② 在提升单个算法预测精度方面,stacking方法的性能优于bagging方法,使用stacking集成SVR和k-NN的地价预测模型精度最高,其平均绝对百分误差仅为8.29%,拟合优度R2达0.814;③ 基于论文所构建模型生成的城市住宅地价分布图能有效表征价格圈层分布特征和局部奇异性。研究结果可为城市住宅地价评估提供新的思路和方法借鉴。  相似文献   

14.
This research sought to understand the role that differentially assessed lands (lands in the United States given tax breaks in return for their guarantee to remain in agriculture) play in influencing urban growth. Our method was to calibrate the SLEUTH urban growth model under two different conditions. The first used an excluded layer that ignored such lands, effectively rendering them available for development. The second treated those lands as totally excluded from development. Our hypothesis was that excluding those lands would yield better metrics of fit with past data. Our results validate our hypothesis since two different metrics that evaluate goodness of fit both yielded higher values when differentially assessed lands are treated as excluded. This suggests that, at least in our study area, differential assessment, which protects farm and ranch lands for tenuous periods of time, has indeed allowed farmland to resist urban development. Including differentially assessed lands also yielded very different calibrated coefficients of growth as the model tried to account for the same growth patterns over two very different excluded areas. Excluded layer design can greatly affect model behavior. Since differentially assessed lands are quite common through the United States and are often ignored in urban growth modeling, the findings of this research can assist other urban growth modelers in designing excluded layers that result in more accurate model calibration and thus forecasting.  相似文献   

15.
《Urban geography》2013,34(5):496-516
The development of new approaches for understanding processes of urban development and their environmental effects, as well as strategies for sustainable management, is essential in expanding metropolitan areas. This study illustrates the potential of linking urban growth and watershed models to identify problem areas and support long-term watershed planning. Sediment is a primary source of nonpoint-source pollution in surface waters. In urban areas, sediment is intermingled with other surface debris in transport. In an effort to forecast the effects of development on surface-water quality, changes predicted in urban areas by the SLEUTH urban growth model were applied in the context of erosion-sedimentation models (Universal Soil Loss Equation and Spatially Explicit Delivery Models). The models are used to simulate the effect of excluding hot-spot areas of erosion and sedimentation from future urban growth and to predict the impacts of alternative erosion-control scenarios. Ambos Nogales, meaning "both Nogaleses," is a name commonly used for the twin border cities of Nogales, Arizona and Nogales, Sonora, Mexico. The Ambos Nogales watershed has experienced a decrease in water quality as a result of urban development in the twin-city area. Population growth rates in Ambos Nogales are high and the resources set in place to accommodate the rapid population influx will soon become overburdened. Because of its remote location and binational governance, monitoring and planning across the border is compromised. One scenario described in this research portrays an improvement in water quality through the identification of high-risk areas using models that simulate their protection from development and replanting with native grasses, while permitting the predicted and inevitable growth elsewhere. This is meant to add to the body of knowledge about forecasting the impact potential of urbanization on sediment delivery to streams for sustainable development, which can be accomplished in a virtual environment.  相似文献   

16.
城市规划CA模型及其应用   总被引：2，自引：2，他引：0  
基于CA模型,从城市规划角度,通过引入控制性详细规划层,将整个城市空间划分为不同组团片区,构建了自下而上和自上而下相结合的城市规划CA模型(UPCA),并以长沙市为例进行实证研究。结果表明:该模型简化了传统CA城市模拟模型的数据量,提高了模型的模拟精度,并增强了模型的规划决策功能,使模型具备一定的社会经济分析能力。  相似文献   

17.
如何更好地进行城市发展模拟是发展中国家快速城市化过程中面临的一个科学问题。传统研究往往基于单体或组合模型,不能为决策方案提供直接支持。本文介绍了国外一个新的城市发展模型FUTURES(FUTure Ur-ban-Regional Environment Simulation)。该模型不仅考虑了城市发展区动态适宜性梯度计算、人均土地消耗的趋势分析以及基于空间位置的斑块变化可视化模拟,而且注重模块间的动态交互反馈过程,形成了独有的深度耦合机制,模型结构紧密又不失灵活性。基于高性能计算环境支持,该模型已经在美国北卡罗来纳州的多个区域进行实验并取得成功。本文主要介绍该模型设计思想、模型组成、关键建模方法,并总结了模型的主要优势,以期为我国城市发展模拟研究提供借鉴。  相似文献   

18.
董冠鹏  张航  郭雨臣 《地理研究》2023,42(2):495-513
在经济全球化、区域一体化的背景下,城市发展动力由内部功能集聚转向外部关系协调,城市间的关联作用愈发重要,成为“城市的第二本质”。通过文献计量分析,发现空间计量模型逐渐成为城市网络外部性定量测度的主要方法之一。从研究设计角度,空间计量模型作为城市网络外部性的定量建模工具,存在至少两方面的问题：城市网络外部性的非对称效应和城市网络的多尺度问题。本文结合城市网络外部性测度与建模,首先阐述如何规范地解读空间计量模型参数及其与网络外部性测度的对应关系;其次基于蒙特卡洛模拟实验论证非对称城市网络外部性和多尺度城市网络外部性的建模方法。研究表明：(1)忽视城市网络外部性中潜在的非对称效应会显著降低模型参数估计的准确性,本文开发的非对称空间效应模型（Asymmetric Spatial Econometric Model,ASEM）可以准确识别网络外部性的非对称效应,给出更加准确的参数估计;(2)忽略现实存在的多尺度网络效应,只在单一尺度对网络效应建模会造成参数估计失真,而空间多尺度统计模型（Hierarchical Spatial Autoregressive model,HSAR）为多尺度网络外部...  相似文献   

19.
《Urban geography》2013,34(8):1100-1117
Metropolitan areas today are faced with pervasive changes of their urban spatial structure and are reshaped by postsuburbanization processes. In this study, one example of such postsuburban restructuring, the multinucleated monofunctional clustering of higher-order services, is investigated in the urban fringe of Vienna, Austria. The methodological framework uses microgeographic data for 2006 and applies a case-control point process modeling approach, which accounts for nonstationarity in first-order effects. The results show a relocation of highly specialized firms into the outer metropolitan ring, where these firms provide functional enrichment. This disagrees with the classical notion of a central place hierarchy. The urban fringe thus increasingly conforms to the core city. This spatial functional agglomeration shows statistically significant evidence of a bicentric urban structure, with the two new subcenters located in traditional suburban areas. Accordingly, Vienna's urban fringe is being altered by new postsuburban forms.  相似文献   

20.
顾及城市空间结构信息的元胞自动机模型构建及其应用   总被引：2，自引：2，他引：0  
利用衡量新增斑块空间邻接关系的多阶景观扩张指数定量识别城市组团的空间特征,结合城市组团所表现出的城市空间结构信息,构建基于MLEI的元胞自动机城市扩展（MLEI-CA）模型。针对武汉市1990、2000、2013年3期遥感影像数据,运用MLEI-CA对武汉市城市扩展进行模拟,通过与Logistic-CA模型对比验证该模型的适用性。研究结果表明,MLEI-CA模型更加准确地揭示城市扩展的空间演变过程,MLEI-CA模型精度优于Logistic-CA模型,Kappa系数、城市用地的精度分别提高6%和4%。  相似文献   

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