Assessing the visual impacts of new urban features: coupling visibility analysis with 3D city modelling

Abstract

Land use changes associated with urbanization often have negative impacts on scenic beauty. In this paper, we explore and compare the visual impact of two different scenarios of urban growth including historical urban growth (HUG) and aesthetically sound urban growth (AUG) with two different categories of height for buildings in the city of Gorgan, Iran. This was done by viewshed and landscape metric analysis of different viewpoints and 3D representation of each scenario. The results show that with the AUG scenario, viewsheds are less impacted by new developments than the HUG scenario in all the viewpoints. It can be concluded that building locations can considerably affect the landscape visibility while building height does not impact to the same degree as location. The results of this research, as a Spatial Decision Support System, would help the managers for better understanding of different patterns of urbanization and its effect on landscape view.     

Designing an integrated urban growth prediction model: a scenario-based approach for preserving scenic landscapes

Abstract

This study demonstrates the integration of landscape aesthetic quality and probable urban growth patterns in urban landscape modelling. This was performed using SLEUTH as a scenario-based urban growth model in Gorgan City of Iran. Future urbanization was predicted under developing three different scenarios including historical, managed and aesthetically sound urban growth up to the year 2030. Multi-Layer Perceptron neural network model was conducted for mapping the aesthetic suitability of the study area. The aesthetic suitability layer was used in the third scenario of SLEUTH model as the excluded layer to protect the scenic patches in future. The results showed that by correct implementation of urban growth policies, 323 ha in the second scenario and 650 ha in the third scenario would be saved. This integrated model would help the planners for a better management of urban landscapes as a Spatial Decision Support System.     

Integrating spectral and non-spectral data to improve urban settlement mapping in a large Latin-American city

ABSTRACT

Information on urban settlements is crucial for sustainability planning and management. While remote sensing has been used to derive such information, its applicability can be compromised due to the complexity in the urban environment. In this study, we developed a remote sensing method to map land cover types in a large Latin-American city, which is well known for its mushrooming unplanned and informal settlements. After carefully considering the landscape complexity there, we designed a data fusion method combining multispectral imagery and non-spectral data for urban and land mapping. Specifically, we acquired a cloud-free Landsat-8 image and two non-spectral datasets, i.e., digital elevation models and road networks. Then, we implemented a set of experiments with different inputs to evaluate their merits in thematic mapping through a supervised protocol. We found that the map generated with the multispectral data alone had an overall accuracy of 73.3% but combining multispectral imagery and non-spectral data yielded a land cover map with 90.7% overall accuracy. Interestingly, the thermal infrared information helped substantially improve both the overall and categorical accuracies, particularly for the two urban classes. The two types of non-spectral data were critical in resolving several spectrally confused categories, thus considerably increasing the mapping accuracy. However, the panchromatic band with higher spatial resolution and its derived textural measurement only generated a marginal accuracy improvement. The novelties of our work are with the successful separation between the two major types of urban settlements in a complex environment using a carefully designed data fusion approach and the insight into the relative merits of the thermal infrared information and non-spectral data in helping resolve the issue of class ambiguity. These findings should be valuable in deriving accurate urban settlement information which can further advance the research on socio-ecological dynamics and urban sustainability.     

Geo-questionnaires in urban planning: recruitment methods,participant engagement,and data quality

ABSTRACT

Recent focus on sustainable urban development and livability has increased the demand for new data sourcing techniques to capture experiences and preferences of urban dwellers. At the same time, developments of geospatial technologies and social media have enabled new types of user-generated geographic information and spatially explicit online communication. As a result, new public participation GIS methods for engaging large groups of individuals have emerged. One such method is geo-questionnaire, an online questionnaire with mapping capabilities, which has been used to elicit geographic data in variety of topics and geographical contexts. This article presents two recent cases, in which geo-questionnaires have been used in Polish cities to obtain public input on quality of life and development preferences in local land use planning. The article evaluates participant recruitment methods focusing on sample representativeness, participant engagement, and data quality. Recruitment via social media was found to increase bias towards younger population. Paper questionnaires used along the online version provided for better representation of target population’s age structure, but did not reduce bias related to educational attainment. We discuss how these issues relate to data usability and generalizability in the context of digital divide, and suggest directions for future research.     

The Generalised Settlement Area: mapping the Earth surface in the vicinity of built-up areas

ABSTRACT

Geo-information on settlements from Earth Observation offers a base for objective and scalable monitoring of the evolution of cities and settlements, including their location, extent and other attributes. In this work, we deploy the best available global knowledge on the presence of human settlements and built-up structures derived from Earth Observation to advance the understanding of the human presence on Earth. We start from a concept of Generalised Settlement Area to identify the Earth surface within which any built-up structure is present. We further characterise the resulted map by using an agreement map among the state of the art of remote sensing products mapping built-up areas or other strictly related semantic abstractions as urban areas or artificial surfaces. The agreement map is formed by a grid of 1?km², where each cell is classified according to the number of EO-derived products reporting any positive occurrence of the abstractions related to the presence of built-up structures. The paper describes the characteristics of the Generalised Settlement Area, the differences in the agreement map across geographic regions of the world, and outlines the implications for potential users of the EO-derived products used in this study.     

Large-scale urban functional zone mapping by integrating remote sensing images and open social data

ABSTRACT

Urban functional zones (UFZs) are important for urban sustainability and urban planning and management, but UFZ maps are rarely available and up-to-date in developing countries due to frequent economic and human activities and rapid changes in UFZs. Current methods have focused on mapping UFZs in a small area with either remote sensing images or open social data, but large-scale UFZ mapping integrating these two types of data is still not be applied. In this study, a novel approach to mapping large-scale UFZs by integrating remote sensing images (RSIs) and open social data is proposed. First, a context-enabled image segmentation method is improved to generate UFZ units by incorporating road vectors. Second, the segmented UFZs are classified by coupling Latent Dirichlet Allocation (LDA) and Support Vector Machine (SVM). In the classification framework, physical features from RSIs and social attributes from POI (Point of Interest) data are integrated. A case study of Beijing was performed to evaluate the proposed method, and an overall accuracy of 85.9% was achieved. The experimental results demonstrate that the presented method can provide fine-grained UFZs, and the fusion strategy of RSIs and POI data can distinguish urban functions accurately. The proposed method appears to be promising and practical for large-scale UFZ mapping.     

Sensing Sprawl: Towards the Monitoring of Urban Expansion Using Dempster‐Shafer Theory

Abstract

The outward expansion of cities in the United States has been a source of concern and policy debate for well over forty years. This sprawling urban landscape has been cited as a contributing factor behind the loss of open space, environmental damage and increased congestion. To better understand urban expansion, monitoring programs are required to facilitate the systematic observation of urban expansion, and to provide critical information in order to adjust urban development policies. Monitoring the urban landscape has been a major application focus of satellite remote sensing technologies. Yet, research has shown that the complexity of the urban landscape frustrates simple characterization of cumulative land cover processes such as sprawl. In this paper an approach to the remote detection and characterization of sprawl is introduced based on the use of Dempster‐Shafer Theory of Evidence. Functioning as a soft‐classification algorithm, Demptster‐Shafer Theory offers a unique solution to the mapping problem when evidence of class structure in underscored by uncertainty. Through the use of this technique it was possible to model uncertainty based on the concept of belief. This conceptualization was instrumental in deciphering the complexities of urban land cover arrangements and offered an alternative logic which enhanced delineation of subtle changes in land cover indicative of sprawl.     

Monitoring the built-up environment of Shanghai on the street-block level using SAR and volunteered geographic information

ABSTRACT

In this geo-statistical analysis of change detection, we illustrate the evolution of the built-up environment in Shanghai at the street-block level. Based on two TerraSAR-X image stacks with 36 and 15 images, covering the city centre of Shanghai for the time period from 2008 to 2015, a set of coherence images was created using a small baseline approach. The road network from Open Street Map, a volunteered geographic information product, serves as the input dataset to create street-blocks. A street-block is surrounded by roads and resembles a ground parcel, a real estate property – a cadastral unit. The coherence information is aggregated to these street-blocks for each observation and the variation is analysed over time. An analysis of spatial autocorrelation reveals clusters of similar behaviours. The result is a detailed map of Shanghai highlighting areas of change. We argue that the aggregation and grouping of synthetic aperture radar coherence image information to real-world entities (street-blocks) is comprehensible and relevant to the urban planning process. Therefore, this research is a contribution to the community of urban planners, designers, and government agencies who want to monitor the development of the urban landscape.     

Mapping 3D visibility in an urban street environment from mobile LiDAR point clouds

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.     

Visual Encoding of Acoustic Parameters – Framework and Application to Noise Mapping

Abstract

Along with an increasing importance and awareness of sonic phenomena related to the human environment, there is a growing need for a comprehensive communication of sound information. The central goal of this contribution is the development of a systematic and comprehensive framework that considers the particular properties of sound phenomena. This framework is structured according to the acoustic quantities that shall be represented and consists of recommendations for their cartographical encoding. A proof of concept is given through the application to official strategic noise maps in the course of the Environmental Noise Directive. Those maps suffer from several weaknesses from a cartographical point of view (e.g. concerning colour schemes or band-like illustrations) which can be eliminated by applying some of the mentioned recommendations. Finally, it will be possible to derive valuable knowledge from our results for multimodal encoding and value transformation between senses.     

公路走廊带景观破碎度的空间分异研究

近年来,我国公路对自然生态环境的影响随着通车里程的增加而日益显著。在公路选线的过程中,全面分析拟建公路走廊带内景观破碎度的空间分异特征,可有效减少公路修建对生态环境的不利影响。本文利用遥感分类技术和GIS(地理信息系统)空间分析方法,以湖南长湘公路走廊带某段土地斑块和景观分类为基础,借助斑块密度指数、最大斑块指数和相似邻近比指数,在斑块类型水平和景观水平两个层面全面分析公路走廊带内自然林地景观、农业景观和城乡建设景观破碎度的空间分异特征。结果表明:长湘公路走廊带内景观破碎度高的地区主要分布在大型斑块边缘、平原地区以及公路沿线;自然林地景观和农业景观的破碎度较低,城乡建设景观的破碎度较高;城乡建设景观的破碎度与公路相关性最强,表现出顺应公路走向的条带状蔓延特征。该研究成果可为公路选线方案的制订和完善提供环境影响方面的参考。     

Multi-resolution integration of land cover for sub-pixel estimation of urban impervious surface and forest cover

Abstract

A methodology is presented for estimating percent coverage of impervious surface (IS) and forest cover (FC) within Landsat thematic mapper (TM) pixels of urban areas. High-resolution multi-spectral images from Quickbird (QB) play a key role in the sub-pixel mapping process by providing information on the spatial distributions of ISs and FCs at 2.4 m ground sampling intervals. Thematic classifications, also derived from the Landsat imagery, have then been employed to define relationships between 30 m Landsat-derived greenness values and percent IS and FC. By also utilizing land cover/land use classification derived from Landsat and defining unique relationships for urban sub-classes (i.e. residential, commercial/industrial, open land), confusion between impervious and fallow agricultural lands has been overcome. Test results are presented for Ottawa-Gatineau, an urban area that encompasses many aspects typical of the North American urban landscape. Multiple QB scenes have been acquired for this urban centre, thereby allowing us to undertake an in-depth study of the error budgets associated with the fractional inference process.     

美丽乡村地理信息系统的设计与实现

为推动城乡一体化建设,以信息化带动城乡统筹,提升美丽乡村建设品质,在数字城市地理空间框架建设项目的推动下,结合新农村建设测绘保障服务和美丽乡村建设计划,利用地理信息资源和技术,开展美丽乡村地理信息系统建设,以提升美丽乡村建设的信息化水平,促进地理信息资源的深层次应用,推动城乡一体化发展。     

Refugee Camp Mapping Using Very High Spatial Resolution Satellite Sensor Images

Abstract

Short time‐intervals for complex response in unfamiliar areas cause refugee‐relief organisations to have a strong need for timely and up‐to‐date geographic information of the environment during humanitarian operations. The objective of this study is to provide an overview of relief organisations' need for detailed geographic information, and to assess the potential of the upcoming very high spatial resolution (VHSR) satellite sensors to provide this geographic information by mapping refugee camps and their environment on an operational basis. To demonstrate the use of VHSR satellite technology in relief operations, a pilot proof‐of‐concept study using a 1992 Russian KVR‐lOOO 2 m resolution panchromatic image of the six refugee camps in the Qala en Nahal settlement scheme in the Sudan was performed. The VHSR satellite sensor image was found to be useful for mapping refugee camp environmental parameters, such as land use, roads, rivers, and water sources, as well as camp infrastructure, including geographic positioning of camps, housing, and street network. The image also allowed for detailed camp area estimates. In addition, a statistically significant relationship between camp area and population was revealed for refugee camps included in this study. In operational use of VHSR satellite sensor data, relief agencies should be aware of the limitations of optical satellite images, in particular their reduced applicability during cloudy conditions.     

Monitoring Intraurban temperature patterns and associated land cover in phoenix,Arizona using Landsat thermal data

Abstract

This study investigates urban climatologic modification associated with development and changing land use in the relatively arid urban environment of Phoenix, Arizona. An analysis of surface temperatures, as portrayed on Landsat thermal remotely sensed data, were compared to current land use patterns in regions of the rapidly expanding urban landscape. A second focus of this study involved investigation of the surface temperatures of this environment, as extracted from the radiometric data of the Landsat thermal band, to provide insights into the complexities of the relationship to the near‐surface atmospheric temperature, a parameter used extensively in climate change analyses and in models for energy and water demand in this desert region. The near surface air temperature is usually measured approximately two meters above the ground surface. In general, spatial temperature patterns of the metropolitan region were strongly correlated with the presence of open water or biomass which provide an evapotranspirative heat sink.     

Measuring the effect of an ongoing urbanization process on biodiversity conservation suitability index: integrating scenario-based urban growth modelling with Conservation Assessment and Prioritization System (CAPS)

The present study adopts an integrative modelling methodology, which combines the strengths of the SLEUTH model and the Conservation Assessment and Prioritization System (CAPS) method. By developing a scenario-based geographic information system simulation environment for Hashtpar City, Iran, the manageability of the landscape under each urban growth scenario is analysed. In addition, the CAPS approach was used for biodiversity conservation suitability mapping. The SLEUTH model was implemented to generate predictive urban layers of the years 2020, 2030, 2040 and 2050 for each scenario (dynamic factors for conservation suitability mapping). Accordingly, conservation suitability surface of the area is updated for each time point and under each urban development storyline. Two-way analysis of variance and Duncan’s new multiple range tests were employed to compare the functionality of the three scenarios. Based on results, the managed urban growth scenario depicted better results for manageability of the landscape and less negative impact on conservation suitability values.     

Photographic,Polyfocal and Polar-Diagrammatic Mapping of Atmospheric Pollution

Abstract

In order to display, predict and combat atmospheric pollution, suitable graphics should be employed. The author proposes some new methods of representation such as mapping air pollution on an air photograph which is printed through screens proportional to air purity, or using the Polyfocal Projection for mapping airport noise. Polar diagrams are used to depict atmospheric stability states.     

利用农村地籍调查成果更新地理信息公共平台居民地方法研究

省级地理信息公共服务平台数据的快速更新是困扰测绘生产单位的难题,通过试验利用同期完成的大比例尺农村地籍调查成果具有现势性强、精度高的优势,找准该数据用于DLG更新的切入点,对农村地籍要素进行分类与提取,基于自动综合更新技术模式,完成同期城乡数据的衔接及整合,实现行政区划单元范围1∶10 000DLG居民地要素快速更新,为以后省级地理信息公共服务平台数据的快速更新提供新思路。     

检索应用中地理信息资源相似度计算方法研究

在地理信息资源检索应用中,资源属性间相似关系的计算还不够深入,地理信息资源的精准推荐及检索可视化应用尚难以实现。针对该问题,统一采用"相似度"对资源属性间的相似关系进行表达。资源的属性类型大部分为文本,其中具有语义差异,文中提出复合文本的相似度算法对文本类型属性进行匹配,并给出数值类型属性的"相似度"映射方案。在此基础上,实现资源时间、空间属性的相似度计算。基于所提出的相似度算法进行地理信息资源检索实验,实现地理信息资源属性间相似关系的量化,促进信息可视化在地理信息资源检索中的应用。     

Mapping for Cycle Touring in Britain; Past,Present, and a Possible Future

Abstract

The Lack hitherto of studies of cycle-touring mapping in Britain is noted, and some basic attributes of cycle touring, including speed, daily distance, gradients and wind, are described. Essential and desirable qualities for a cycle-touring map are enumerated, including the need to depict all rural routes available to cyclists; it is concluded that the optimum scale is in the range 1:100 000–1:126 720, and that relief should by contours at an interval not greater than 30 metres. National mapping in the optimum scale range which were published after 1945 are then reviewed, and reasons suggested as to why none has been kept in print. The mapping available for cycle touring in Britain in 2001 is Ordnance Survey (OS) 1:50 000 Landranger series contains all the necessary information, it is too bulky to be suitable; and that most of the other maps published in the optimum scale range have inadequate relief information and all offer very limited geographical cover. The potential competition for the OS 1:50 000 from a national map series in the optimum scale range is acknowledged, and an outline specification for a 1:125 000 series is described, which seeks to minimize that competiton whilst providing all the necessary information for cycle touring.