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An enhanced MEMS-INS/GNSS integrated system with fault detection and exclusion capability for land vehicle navigation in urban areas 总被引：2，自引：2，他引：0
We describe an enhanced quality control algorithm for the MEMS-INS/GNSS integrated navigation system. It aims to maintain the system’s reliability and availability during global navigation satellite system (GNSS) partial and complete data loss and disturbance, and hence to improve the system’s performance in urban environments with signal obstructions, tunnels, bridges, and signal reflections. To reduce the inertial navigation system (INS) error during GNSS outages, the stochastic model of the integration Kalman filter (KF) is informed by Allan variance analysis and the application of a non-holonomic constraint. A KF with a fault detection and exclusion capability is applied in the loosely and tightly coupled integration modes to reduce the adverse influence of abnormal GNSS data. In order to evaluate the performance of the proposed navigation system, road tests have been conducted in an urban area and the system’s reliability and integrity is discussed. The results demonstrate the effectiveness of different algorithms for reducing the growth of INS error. 相似文献
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Many methods for modeling urban expansion are available. Most of these computational models demand a variety of large‐scale environmental and socio‐economic data to investigate the relationship between urban expansion and its driving forces. These requirements are not always fulfilled, particularly in developing countries due to a lack of data availability. This necessitates methods not suffering from data limitations to ease their application. Consequently, this research presents a morphological approach for predicting urban expansion on the basis of spatiotemporal dynamics of urban margins by investigating the interior metropolitan area of Tehran, Iran as a case study. To assess the model's performance, urban expansion is monitored from 1976 to 2012. The proposed model is evaluated to ensure that the prediction performance for the year 2012 is acceptable. For the year 2024, the model predicts Tehran's urban expansion at an overall R2 of 88%. Accordingly, it is concluded that: (1) although this approach only inputs urban margins, it represents a suitable and easy‐to‐use urban expansion model; and (2) urban planners are faced with continuing urban expansion. 相似文献
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吕悦 《测绘与空间地理信息》2017,(8)
城市地下管线是城市的"生命线",管线探测的质量控制受到业内专家和作业单位的广泛关注。本文总结了地下管线探测工程质量控制方法,强调了过程质量控制的重要性,可为其他单位城市地下管线探测工程项目提供借鉴和参考。 相似文献
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Since there is an increasing demand for integrating landscape ecology and urban planning theories to study complex urban ecosystems and establish rational and ecological urban planning, we introduced a new concept-urban functional landscapes which can be reclassified based on detailed land use data to fulfill the various urban functions, such as residential, commercial, industrial, and infrastructure purposes. In this paper, urban functional landscapes were defined based on urban land use data produced from Pleiades images, and then landscape metrics and population density were combined to identify the urban functional zones along an urban–rural gradient. The features of urban functional landscape patterns and population density were also analyzed, and their relationship has been explored. The results showed that the pattern of urban functional landscapes and population density in the urban functional zones (Urban center, Urban peripheral area, Landscape barrier, Satellite city and Far-suburb) along the urban–rural gradient in Xiamen doesn't totally conform to the classical theories in spatial and social aspects. Urban functional landscapes is potential of acting as bridges between the landscape ecology and urban planning theories, providing scientific support for rational urban landscape planning and urban land use policy making. 相似文献
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基于夜间灯光数据的南京城镇用地提取 总被引：1，自引：0，他引：1
针对多时相夜间灯光影像无法直接对比的问题,该文提出了一种基于不变目标进行不同年份不同卫星夜间灯光数据的校正方法。在系统校正多时相夜间灯光数据的基础上,应用支持向量机分类算法提取城镇用地信息,并分析1992—2013年南京城镇扩张动态变化规律。结果表明:该数据校正方法可以有效减少年际夜间灯光影像之间的异常差异,提高不同年份数据间的连续性和可比较性;支持向量机分类算法提取的4个样区城镇用地信息总体精度和Kappa系数平均值分别为88.35%和0.56,能够准确反映区域城镇发展的实际情况;1992—2013年南京城镇经历先缓慢后快速的扩张过程,主城区在1992年城镇基础上往四周扩张,并沿长江及南北交通走廊发展。 相似文献
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Understanding the interplay between bus,metro, and cab ridership dynamics in Shenzhen,China 
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下载免费PDF全文 Mengxue Yue Chaogui Kang Clio Andris Kun Qin Yu Liu Qingxiang Meng 《Transactions in GIS》2018,22(3):855-871
The most common mass transit modes in metropolitan cities include buses, subways, and taxicabs, each of which contribute to an interconnected complex network that delivers urban dwellers to their destinations. Understanding the intertwined usages of these three transit modes at different places and time allows for better sensing of urban mobility and the built environment. In this article, we leverage a comprehensive data collection of bus, metro, and taxicab ridership from Shenzhen, China to unveil the spatio‐temporal interplay between different mass transit modes. To achieve this goal, we develop a novel spectral clustering framework that imposes spatio‐temporal similarities between mass transit mode usage in urban space and differentiates urban spaces associated with distinct ridership patterns of mass transit modes. Five resulting categories of urban spaces are identified and interpreted with auxiliary knowledge of the city's metro network and land‐use functionality. In general, different categorized urban spaces are associated with different accessibility levels (such as high‐, medium‐, and low‐ranked) and different urban functionalities (such as residential, commercial, leisure‐dominant, and home–work balanced). The results indicate that different mass transit modes cooperate or compete based on demographic and socioeconomic attributes of the underlying urban environments. Our proposed analytical framework provides a novel and effective way to explore the mass transit system and the functional heterogeneity in cities. It demonstrates great potential for assisting policymakers and municipal managers in optimizing public transportation facility allocation and city‐wide daily commuting distribution. 相似文献
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ABSTRACTThis paper provides a study of the changes in land use in urban environments in two cities, Wuhan, China and western Sydney in Australia. Since mixed pixels are a characteristic of medium resolution images such as Landsat, when used for the classification of urban areas, due to changes in urban ground cover within a pixel, Multiple Endmember Spectral Mixture Analysis (MESMA) together with Super-Resolution Mapping (SRM) are employed to derive class fractions to generate classification maps at a higher spatial resolution using an Artificial Neural Network (ANN) predicted Wavelet method. Landsat images over the two cities for a 30-year period, are classified in terms of vegetation, buildings, soil and water. The classifications are then processed using Indifrag software to assess the levels of fragmentation caused by changes in the areas of buildings, vegetation, water and soil over the 30 years. The extents of fragmentation of vegetation, buildings, water and soil for the two cities are compared, while the percentages of vegetation are compared with recommended percentages of green space for urban areas for the benefit of health and well-being of inhabitants. Changes in Ecosystem Service Values (ESVs) resulting from the urbanization have been assessed for Wuhan and Sydney. The UN Sustainable Development Goals (SDG) for urban areas are being assessed by researchers to better understand how to achieve the sustainability of cities. 相似文献
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了解城市污染状况是治理城市污染的首要环节。社交媒体中包含了能够反映人们对周围环境的感受的数据资料,可以帮助人们更直观地了解城市污染现状。本文以新浪微博为例,提出了从社交媒体中获取城市污染相关数据的方案,设计了基于社交媒体的城市污染信息分类法和可视化方法,在实验部分以北京市为例对本方法的结果进行了分析与讨论。 相似文献
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J. -P. Montillet G. W. Roberts C. Hancock X. Meng O. Ogundipe J. Barnes 《Journal of Geodesy》2009,83(2):91-103
Locata is a new positioning technology developed by the Locata Corporation. At the beginning of 2007, the Institute of Engineering
Surveying and Space Geodesy (IESSG) bought and received a network of Locata transceivers with two rovers. The purpose is to
solve the challenges identified when surveying in dense multipath areas (i.e. urban canyons). In this paper, the technology
is tested in an urban canyon scenario on the University park at the University of Nottingham. By comparing Locata position
solutions with the true positions calculated with a total station and a carrier-phase GPS, the results show that centimetre-level
accuracy is achievable in difficult environments in the presence of Wi-Fi signals. The rover’s estimated coordinates may diverge
in some cases. Finally, a comparison study shows that Real Time Kinematic GPS and Locata technologies have similar accuracy
when both are available. 相似文献
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Peter Caccetta Simon Collings Andrew Devereux Kassell Hingee Don McFarlane Anthony Traylen 《International Journal of Digital Earth》2016,9(5):457-475
This paper describes the development of a system for decimetre-scale monitoring of land-surface and land-cover in urban and peri-urban environments. We describe our methodology that comprises the application of highly automated processing and analysis methods to digital aerial photography. The approach described in this paper addresses a monitoring need by providing the ability to generate change information at a spatial resolution suitable for urban, peri-urban and coastal areas, where an increasing percentage of the worlds’ population dwells. These areas are dynamic, with many environmental issues associated with planning, service provision, resource management and allocation, as well as monitoring regulatory compliance. We present a system based on standardised data and methods, which is able to track and communicate changes in features of interest in a way that has not been previously possible. We describe the methodology and then demonstrate its feasibility by applying it to geographic areas of planning and policy relevant size (the order of tens of thousands of square kilometres). We demonstrate the approach by applying it to the problem of urban forest assessment. 相似文献
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Yulun Zhou 《制图学和地理信息科学》2016,43(5):379-392
ABSTRACTIn the past decade, an explosion of data has taken place in Chinese cities due to widespread use of mobile Internet devices, Web 2.0 applications, and the development of the “Wired City.” With advances in data storage and high-performance computing, big/open urban data have opened up important avenues for urban studies, planning practice, and commercial consultancy. Urban researchers and planners are eager to make use of these abundant, sophisticated, and dynamic data to deepen their understanding on urban form and functions. However, in practice, access to such urban data is limited in China due to institutional constraints on data distribution and data holders’ hesitation to share data. And this hampers urban analytics. To draw reliable conclusions about the workings of complex urban systems, efficient and effective interoperation of multisource urban datasets is needed. Also, dealing with the heterogeneity between datasets is an equally critical challenge, especially for urban planners and government officers. They would derive value from data analytics, but have little data processing experience. To address these issues, we initiated SinoGrids (Plan Xu Xiake), a crowdsourcing platform that standardizes (or “downscales”) microscale urban data in China to facilitate its sharing and interoperation. To assess the performance evaluation of SinoGrids, we propose field-testing with actual urban data and their potential users. Digital desert, a son project of SinoGrids is also included. 相似文献
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ABSTRACT Visibility determination is a key requirement in a wide range of national and urban applications, such as national security, landscape management, and urban design. Mobile LiDAR point clouds can depict the urban built environment with a high level of details and accuracy. However, few three-dimensional visibility approaches have been developed for the street-level point-cloud data. Accordingly, an approach based on mobile LiDAR point clouds has been developed to map the three-dimensional visibility at the street level. The method consists of five steps: voxelization of point-cloud data, construction of lines-of-sight, construction of sectors of sight, construction of three-dimensional visible space, and calculation of volume index. The proposed approach is able to automatically measure the volume of visible space and openness at any viewpoint along a street. This approach has been applied to three study areas. The results indicated that the proposed approach enables accurate simulation of visible space as well as high-resolution (1 m × 1 m) mapping of the visible volume index. The proposed approach can make a contribution to the improvement of urban planning and design processes that aim at developing more sustainable built environments. 相似文献
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夜间灯光遥感对城市发展类动能与相似性评估 总被引：2，自引：0，他引：2
评估城市发展水平与制定城市规划和城市发展政策息息相关。已有研究表明人口、国内生产总值(GDP)等统计数据和夜间灯光遥感数据能够用来衡量城市发展水平,但大多研究只关注城市发展总量,忽视了发展速度对城市发展的影响。因此,本文基于2012年—2019年Suomi NPP-VIIRS (Suomi National Polar-OrbitingPartnership-Visible Infrared Imaging Radiometer Suite)夜间灯光遥感数据,提出了兼顾城市发展水平和增速的夜间灯光类动能指数用于测度城市发展类动能;利用动态时间规整DTW (Dynamic Time Warping)算法构建了城市发展类动能相似性检测分析框架,并基于相似性检测结果对全国328个城市进行了等级划分。相较于2019年第一财经公布的一至五线城市,本文城市等级划分结果表明,在同一等级中的城市发展更为相似和合理,也证明了城市发展类动能更有利于城市发展水平的评估;以长江三角洲城市群为例,进一步验证了城市发展类动能和基于DTW相似性检测方法用于评估城市群发展情况与合理性的潜力。综上所述,基于夜间灯光遥感的城市发展类动能估算与相似性分析方法能够较好地评估城市发展水平,为城市分级与城市群发展评估提供科学依据。 相似文献
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Serkan Ural Ejaz Hussain Jie Shan 《International Journal of Applied Earth Observation and Geoinformation》2011
Geospatial distribution of population at a scale of individual buildings is needed for analysis of people's interaction with their local socio-economic and physical environments. High resolution aerial images are capable of capturing urban complexities and considered as a potential source for mapping urban features at this fine scale. This paper studies population mapping for individual buildings by using aerial imagery and other geographic data. Building footprints and heights are first determined from aerial images, digital terrain and surface models. City zoning maps allow the classification of the buildings as residential and non-residential. The use of additional ancillary geographic data further filters residential utility buildings out of the residential area and identifies houses and apartments. In the final step, census block population, which is publicly available from the U.S. Census, is disaggregated and mapped to individual residential buildings. This paper proposes a modified building population mapping model that takes into account the effects of different types of residential buildings. Detailed steps are described that lead to the identification of residential buildings from imagery and other GIS data layers. Estimated building populations are evaluated per census block with reference to the known census records. This paper presents and evaluates the results of building population mapping in areas of West Lafayette, Lafayette, and Wea Township, all in the state of Indiana, USA. 相似文献
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城市的快速扩张导致人地矛盾激化,土地利用效率下降.分析并预测城市发展状态,可以实现土地资源的合理配置,为城市发展提供合理规划.本文以鸡西市市辖区为例,利用Logistic-CA模型进行城市扩张模拟及趋势特征分析.结果表明:1)鸡西市在2005—2015年间城市处于低速扩张阶段,土地利用效率较低,城市发展较为分散;2)通... 相似文献
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AbstractMulti-sensor and multi-resolution source images consisting of optical and long-wave infrared (LWIR) images are analyzed separately and then combined for urban mapping in this study. The framework of its methodology is based on a two-level classification approach. In the first level, contributions of these two data sources in urban mapping are examined extensively by four types of classifications, i.e. spectral-based, spectral-spatial-based, joint classification, and multiple feature classification. In the second level, an objected-based approach is applied to decline the boundaries. The specificity of our proposed framework not only lies in the combination of two different images, but also the exploration of the LWIR image as one complementary spectral information for urban mapping. To verify the effectiveness of the presented classification framework and to confirm the LWIR’s complementary role in the urban mapping task, experiment results are evaluated by the grss_dfc_2014 data-set. 相似文献
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Falguni Mukherjee 《制图学和地理信息科学》2018,45(6):556-569
Government organizations in the developing world have been at the forefront of ongoing reforms that have prompted their use of GIS and other information and communication technologies for urban governance. However, there have been very few examinations of GIS spatial knowledge construction in a non-Western context. Particularly, very little is known about the growing and varying use of GIS and spatial information by urban local bodies in India in the midst of India’s changing urban governance culture. This article presents an in-depth examination of Surat Municipal Corporation (SMC), one of India’s leading urban local bodies as the corporation implements e-governance strategies including the use of GIS and spatial information. Drawing from Critical GIS literature and GIS implementation and diffusion literature, this article uses an integrated approach to examine SMC’s GIS spatial knowledge construction. The article demonstrates that in the case of SMC, GIS knowledge construction is not only shaped by SMC’s proactive role in positioning itself with the national government’s priorities and agendas, but also by the presence of powerful actors who play an instrumental role in introducing change and innovation. This article is part of a larger project that aims to investigate the process of GIS spatial knowledge construction situated in contemporary India. 相似文献