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Spatial prediction is commonly used in social and environmental research to estimate values at unobserved locations using sampling data. However, most existing spatial prediction methods and software packages are based on the assumption of spatial autocorrelation (SAC), which may not apply when spatial dependence is weak or non-existent. In this article, we develop a modeling framework for spatial prediction based on spatial stratified heterogeneity (SSH), a common feature of geographical variables, as well as an R package called sandwichr that implements this framework. For populations that can be stratified into homogeneous strata, the proposed framework enables the estimation of values for user-defined reporting units (e.g., administrative units or grid cells) based on the mean of each stratum, even if SAC is weak or absent. The estimated values can be used to create predicted surfaces and mapping. The framework also includes procedures for selecting appropriate stratifications of the populations and assessing prediction uncertainty and model accuracy. The sandwichr package includes functions to implement each step of the framework, allowing users to implement SSH-based spatial prediction effectively and efficiently. Two case studies are provided to illustrate the effectiveness of the proposed framework and the sandwichr package. 相似文献
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传统的电视电话会议,由于空间地域差异或者专业知识的限制,使信息沟通不完整,表述复杂,给会商参与者造成沟通交流障碍。在此基础上,增加分布式地理信息系统,可以使异地参会者实时协作完成各类专题地图制作,增强参会者对会商内容的快速理解,沟通更加便捷,提高会商质量。本文提出灾害应急会商中会议发起人——参会者模式的地图协同标绘应用,研究了会商期间的标绘消息网络推送,实现异地用户对图形标绘信息的远程同步感知,设计了协同编辑指定图元的并发控制流程,分析图元标绘并发操作时的冲突可能性,并提出系统自动裁决、用户协商、权威仲裁的避免冲突策略。文章以玉树地震为应用实例,讲述了民政部利用本系统将远程专家会商结果绘制了物资调配态势图,实现了辅助决策。 相似文献
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目前主要的野外成图方法有电子平板测图、野外画草图法、编码法测图等,但每种方法都有一定的不足,为了克服这些不足,编辑了一种以一位或两位数字做为简易编码并使其与地物的全码相对照,制定相应的连接规则。内业在绘图软件上开发挂件,在展点过程中实现独立地物的自动展绘以及规则地物的自动成图,经屏幕编辑完成后,再通过图形清理程序进行图形整饰工作最终生成地形图。 相似文献
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地缘环境分析模型图形化建模 总被引：2，自引：0，他引：2
针对日益增加的地缘环境分析模型(GEAM)组织管理需求,在对当前GEAM进行元模型剖分及分类的基础上,重点对GEAM图形化建模进行研究。将图形化建模任务划分为模型组织管理、模型编辑及模型验证与运行3个模块,界定各模块的主要功能,构建GEAM图形化建模框架。利用面向对象思想对图元语义映射与关联、模型验证与运行、模型输出与加载等关键技术进行深入研究与剖析。开发GEAM图形化建模原型系统,并通过对地缘环境单元划分模型进行图形化组建,验证可行性。 相似文献
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《International Journal of Digital Earth》2013,6(2):165-183
This paper presents a new spatial data model based on trapezoidal-mesh for implementing spatial operations within geographical information systems (GIS). Based only on the solid foundation of spatial operations, diversified application models can be established to bridge the gap between Digital Earth models and the real world with its real-world problems (‘connecting through location’). In this paper, the involved polygon features are decomposed into a series of trapezoidal-meshes. Then, geo-processing operations are employed on these meshes rather than the original polygon features, resulting in a relatively simple spatial computation. As a kind of model designed by integrating raster with vector, the model presented here has advantages over other models when carrying out spatial operations insofar as providing a solid foundation for achieving the grand goal of Digital Earth. The concept of this data model and the two extensive examples of its application in spatial operations are elaborated upon in this article. As a result, this article and the research that supports it, proves that the adoption of the trapezoidal-mesh model greatly improves the efficiency of spatial operations in GIS. 相似文献
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基于V9I的空间关系映射与操作 总被引：4，自引：0，他引：4
利用V9I模型中目标的边界、内部和Voronoi区域均可量测及易于操作的特点 ,研究建立底层数据结构与空间关系语义层之间的V9I映射机制 ,在Voronoi的动态栅格生成算法的基础上 ,构建空间关系的基本操作。最后 ,以VC 为开发工具并采用面向对象的技术 ,设计了基于V9I的空间关系操作工具原型VTKit ,并给出部分操作实例 相似文献
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一种遥感影像核变化检测方法 总被引：1，自引：0，他引：1
提出了一种新的遥感影像核变化检测方法。该方法是将原始空间不同时相的输入矢量通过核函数非线性映射到高维特征空间，然后在高维特征空间中通过传统变化检测方法处理得到新的输入矢量，最后通过半监督的单类支持向量机算法对新的输入矢量构造变化区域与非变化区域的最优分割超平面。试验证实，本文的核变化检测方法具有较高的检测精度和效率。 相似文献
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Relevance of airborne lidar and multispectral image data for urban scene classification using Random Forests 总被引：3，自引：0，他引：3
Li GuoNesrine Chehata Clément MalletSamia Boukir 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(1):56-66
Airborne lidar systems have become a source for the acquisition of elevation data. They provide georeferenced, irregularly distributed 3D point clouds of high altimetric accuracy. Moreover, these systems can provide for a single laser pulse, multiple returns or echoes, which correspond to different illuminated objects. In addition to multi-echo laser scanners, full-waveform systems are able to record 1D signals representing a train of echoes caused by reflections at different targets. These systems provide more information about the structure and the physical characteristics of the targets. Many approaches have been developed, for urban mapping, based on aerial lidar solely or combined with multispectral image data. However, they have not assessed the importance of input features. In this paper, we focus on a multi-source framework using aerial lidar (multi-echo and full waveform) and aerial multispectral image data. We aim to study the feature relevance for dense urban scenes. The Random Forests algorithm is chosen as a classifier: it runs efficiently on large datasets, and provides measures of feature importance for each class. The margin theory is used as a confidence measure of the classifier, and to confirm the relevance of input features for urban classification. The quantitative results confirm the importance of the joint use of optical multispectral and lidar data. Moreover, the relevance of full-waveform lidar features is demonstrated for building and vegetation area discrimination. 相似文献
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Blogs, micro‐blogs and online forums underpin a more interconnected world. People communicate ever more and are increasingly keen to explain and illustrate their lives; showing where they are and what they are doing. Desktop, online and mobile mapping landscapes have never been as rich or diverse yet this challenges cartography to adapt and remain relevant in the modern mapping world. We explore the spatial expression and potential value of micro‐blogging and Twitter as a social networking tool. Examples of “twitter maps” are reviewed that leverage the Twitter API and online map services to locate some component of the “tweet”. Scope, function and design are illustrated through development of two proof‐of‐concept map mashups that support collaborative real‐time mapping and the organisation and display of information for mass user events. Through the experiments in using and organising data in this way we demonstrate the value of “cartoblography”– a framework for mapping the spatial context of micro‐blogging. 相似文献
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Urban buildings are an integral component of urban space, and accurately identifying their spatial configurations and grouping them is vital for various urban applications. However, most existing building clustering methods only utilize the original spatial and nonspatial features of buildings, disregarding the potential value of complementary information from multiple perspectives. This limitation hinders their effectiveness in scenarios with intricate spatial configurations. To address this, this article proposes a novel multi-view building clustering method that captures cross-view information from spatial and nonspatial features. Drawing inspiration from both spatial proximity characteristics and nonspatial attributes, three views are established, including two spatial distance graphs (centroid distance graph and the nearest outlier distance graph) and a building attribute graph (multiple-attribute graph). The three graphs undergo iterative cross-diffusion processes to amplify similarities within each predefined graph view, culminating in their fusion into a unified graph. This fusion facilitates the comprehensive correlation and mutual enhancement of spatial and nonspatial information. Experiments were conducted using 10 real-world community-building datasets from Wuhan and Chengdu, China. The results demonstrate that our approach achieves 21.27% higher accuracy and 22.28% higher adjusted rand index in recognizing diverse complex arrangements compared to existing methods. These findings highlight the importance of leveraging complementary and consensus information across different feature dimensions for improving the performance of building clustering. 相似文献
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Until recently, land surveys and digital interpretation of remotely sensed imagery have been used to generate land use inventories. These techniques however, are often cumbersome and costly, allocating large amounts of technical and temporal costs. The technological advances of web 2.0 have brought a wide array of technological achievements, stimulating the participatory role in collaborative and crowd sourced mapping products. This has been fostered by GPS-enabled devices, and accessible tools that enable visual interpretation of high resolution satellite images/air photos provided in collaborative mapping projects. Such technologies offer an integrative approach to geography by means of promoting public participation and allowing accurate assessment and classification of land use as well as geographical features. OpenStreetMap (OSM) has supported the evolution of such techniques, contributing to the existence of a large inventory of spatial land use information. This paper explores the introduction of this novel participatory phenomenon for land use classification in Europe's metropolitan regions. We adopt a positivistic approach to assess comparatively the accuracy of these contributions of OSM for land use classifications in seven large European metropolitan regions. Thematic accuracy and degree of completeness of OSM data was compared to available Global Monitoring for Environment and Security Urban Atlas (GMESUA) datasets for the chosen metropolises. We further extend our findings of land use within a novel framework for geography, justifying that volunteered geographic information (VGI) sources are of great benefit for land use mapping depending on location and degree of VGI dynamism and offer a great alternative to traditional mapping techniques for metropolitan regions throughout Europe. Evaluation of several land use types at the local level suggests that a number of OSM classes (such as anthropogenic land use, agricultural and some natural environment classes) are viable alternatives for land use classification. These classes are highly accurate and can be integrated into planning decisions for stakeholders and policymakers. 相似文献
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Huafei Yu Tinghua Ai Min Yang Jingzhong Li Lu Wang Aji Gao Tianyuan Xiao Zhe Zhou 《Transactions in GIS》2023,27(7):1898-1927
Deep learning is increasingly being used to improve the intelligence of map generalization. Vector-based map generalization, utilizing deep learning, is an important avenue for research. However, there are three questions: (1) transforming vector data into a deep learning data paradigm; (2) overcoming the limitation of the number of samples; and (3) determining whether existing knowledge can accelerate deep learning. To address these questions, taking river network selection as an example, this study presents a framework integrating hydrological knowledge into graph convolutional neural networks (GCNNs). This framework consists of the following steps: constructing a dual graph of river networks (DG_RN), extracting domain knowledge as node attributes of DG_RN, developing an architecture of GCNNs for the selection, and designing a fine-tuning rule to refine the GCNN results. Experiments show that our framework outperforms existing machine learning and traditional feature sorting methods using different datasets and achieves good morphological consistency after the selection. Furthermore, these results indicate that DG_RN meets the data paradigm of graph deep learning, and the framework integrating existing characteristics (i.e., Strahler coding, the number of tributaries, the distance between proximity rivers, and upstream drainage area) mitigates the dependence of GCNNs on plenty of samples and enhance its performance. 相似文献