共查询到20条相似文献，搜索用时 46 毫秒
1.
Urban vegetation provides a wide array of services; yet, there is still a knowledge gap regarding the mechanistic processes behind urban vegetation–human well-being relationships. Two main approaches have been used to assess urban greenery associated with human well-being: physical and self-reported. We here assessed the associations between physical (green view index–GVI, green cover–GC) and self-reported measures (perceived visible greenery–PVG) of the streetscape greenery of two southeastern Mexican settlements (Xalapa, Coatepec). Our results show that both sites have considerable GC (Xalapa = 37.2%, Coatepec = 47.4%). We found a clear association between GVI and GC in Xalapa, but none in Coatepec. The latter was due to an important proportion of the vegetation of Coatepec being mainly constrained at block interiors, obstructed by walls. Regarding the self-reported measure, our results show an important discrepancy in relation to one of the physical measures (GVI), assessed through PVG/GVI ratios. In general, respondents tended to overestimate greenery, with greater overestimations related to GVI values <10%. Among the assessed respondent traits (gender, education level, live and/or work in neighborhood, time living and/or working in neighborhood), we found none to explain variations of PVG/GVI ratios in Coatepec, but respondent age did relate, non-linearly, with PVG/GVI ratios in Xalapa. In a nutshell, our findings indicate that the assessed physical and self-reported measures capture different aspects of urban greenery that differ in their potential uses, with GVI representing a helpful tool to quantify visible greenery at eye-level; GC being a highly informative physical measure to assess the amount of public and/or private urban greenery; and PVG as a quick and inexpensive measure of people’s perception of visible urban greenery. Depending on the monitoring, managing, and/or planning goals, the use of the three assessed measures can provide an integral evaluation of urban greenery. 相似文献
2.
Street-side vegetation greenery contributes substantial health benefits for pedestrians. Multi-year street view images are expected to enable the monitoring of dynamic street-side vegetation greenery changes and the development of targeted urban landscape plans. However, the potential of multi-year street view images used for the assessment of street-side vegetation greenery has not been evaluated yet. Besides, complicated urban landscapes may make it difficult to accurately quantify vegetation greenery. This study developed a framework to assess the spatio-temporal variation of street-side vegetation greenery using the Baidu Street View images and a new Vegetation Greenery Index (VGI). The proposed analytical framework was applied to Tai’an city, a highly populated city where urbanization has been rapid in China. The level of vegetation greenery estimated using the proposed framework was compared with ground truths randomly collected at sampling sites along the road networks in 2014 and 2019 to assess the applicability. Results demonstrated that the proposed VGI method could accurately quantify street-side vegetation greenery. The comparison of multi-year VGI layers could identify locations where vegetation greenery substantially changed and quantify the overall change in urban greenery. Vegetation greenery estimates were well agreed with the ground truths. Spatio-temporal variations in the urban vegetation greenery were attributed to trees that were newly planted or removed, the natural growth of the existing vegetation, and new building construction. The proposed framework is expected to be a useful tool to evaluate urban vegetation greenery and help urban landscape planning. 相似文献
3.
Panoramic green view index (PGVI) is an emerging index of urban greenery, which attracts researchers’ attention in recent years. It provides a quantitive method for reflecting real-life feelings about green space in urban areas. The PGVI needs to be calculated from massive datasets, which can be realized by artificial intelligence (AI) techniques. In this work, we used SegNet, an AI semantic segmentation tool, to distinguish urban elements, such as buildings, sky, and people. In total, 6874 panoramic street pictures with an interval of 10 m in the Savannah Historic District were used for the analysis of PGVI and its distribution. Results show that both the PGVI value and its distribution types can reflect the characteristics of regional green space. Good urban greenery can be distributed normally, which also provides a method for greenery classification. The crucial factors influencing PGVI are the trees. Dense low trees with big canopies have a very positive influence. In addition, the grade and width of the road, the parks, and squares along the street also have an impact on PGVI. In Savanah Historic District, the road width of nearly 10 m, and the location near parks and squares, can significantly increase the PGVI of streets. 相似文献
4.
Urban greenery has long been recognized as an important component of urban ecosystem and provides many benefits to urban residents. However, different types of urban greenery provide different kinds of natural experiences to people. In this study, green metrics calculated based on multisource spatial datasets were used to quantify the spatial distribution of different types of urban greenery in Hartford, Connecticut. Geo-tagged Google Street View images, which capture the profile view of cityscape, were used to quantify street greenery by considering the time information. Land cover map and urban parks map were used to measure residential yard greenery and proximity to urban parks, respectively. We analyzed the associations of the calculated green metrics with socio-economic variables derived from census data. Statistical results show that: (1) people with higher income tend to live in neighborhoods with more street greenery; (2) census block groups with a higher proportion of owner-occupied units tend to have more yard vegetation and yard tree/shrub coverage; (3) Hispanics tend to live in block groups that have less yard vegetation but African Americans mostly live in block groups with more yard greenery; and (4) there are no significant environmental disparities among racial/ethnic groups in terms of proximity to urban parks. In general, this study provides an insight into the environments of urban residents in terms of urban greenery, and a valuable reference data for urban planning. 相似文献
5.
Urban greenery is of great significance for sustainable urban development due to the diverse ecosystem services it provides. Assessing urban greenery can reveal its impact on urban areas and provide the evidence base for strategic urban forest management and planning, thereby contributing to sustainable urban development. Street View (SV) images are being used more frequently and widely for assessing urban greenery due to the advantages of providing new perspective and saving workload and research costs. In this paper, 135 peer-reviewed publications that employed SV to assess urban greenery between 2010 and 2022 are reviewed. Presently, the most widely applied area of SV-based urban greenery research is to extract the green view index. Although this has many potential applications for assessing ecosystem services, it has most often been used to date to identify the impact of street greenery on residents' physical and mental health, activities, and well-being (i.e., cultural services). In contrast, fewer studies have explored the other ecosystem services related to the greening. Overall, as an emerging urban environment research method, this review shows that there are still challenges in the utilisation of SV images for assessing urban greenery applications. These include the insufficient spatial and temporal coverage of SV images, low data collection accuracy and immaturity of suitable deep learning techniques on object identification. However, there is clear potential for these approaches to be developed to support a broader range of urban greenery studies that consider different ecosystem services and/or specific types of green infrastructure, for example, street trees. 相似文献
6.
As an important part of urban greening, the canopy of street trees has ecological benefits, such as oxygen production, noise reduction, and dust reduction. The living vegetation volume (LVV) can reflect the spatial structure of the canopy intuitively and enables the estimation of the ecological service value of street trees. Terrestrial laser scanning (TLS) has shown excellent performance for providing three-dimensional data of individual trees with high precision, enabling the accurate quantification of the LVV. In this study, we divided the LVV into the total living vegetation volume (tLVV) and the effective living vegetation volume (eLVV); the latter does not include branches. The eLVV of 40 ginkgo trees separated in two roads in Nanjing was calculated from TLS data. A novel method named LAIM for accurate eLVV calculation based on point cloud data was proposed. The point cloud data of individual tree was segmented along the Z-axis and image processing methods were used. With this, eLVV of each tree was obtained. The results were compared with data obtained from a clustered point cloud generated using convex hulls. The Bland-Altman analysis was used to investigate the consistency of the two methods. Furthermore, we used correlation analysis and all-subsets regression to choose the variables, and the eLVV was fitted using six models. Finally, we evaluated O2 production, CO2 and SO2 absorption by the street trees based on eLVV, the ecological benefits of street trees were quantified. The results showed the following: (1) The number of layers and the dilation size of the point cloud were crucial parameters in the LAIM. (2) For ginkgo trees, the mean difference between the eLVV obtained from the LAIM and the convex hull method was − 0.53–0.19 m3, indicating that the results were highly consistent for the two methods. (3) The eLVV fitting performance was better for the exponential function model (R2 =0.8523, RMSE=0.6838 m3) and linear model (R2 =0.8361, RMSE=0.7224 m3). The tree height and crown width significantly affected the eLVV estimation. (4) The evaluation about ecological benefits of Zhaoyang Road was better than Cuizhu Road. The quantified ecological benefits were conducive to road ecological evaluation. This study quantified the eLVV of individual trees using TLS, highlighting the importance of live vegetation in urban greening. The results can provide technical support for estimating the ecological service value of urban street trees. 相似文献
7.
Urban street trees are part of the bundle of environmental amenities that support healthy social, economic, and environmental functions. In this study, we systematically evaluate the quality of 196,825 street trees at the US. Census tract level in Washington D.C., as well as related impacts from socioeconomic, landscape patterns and environmental factors using Ordinary least-squares (OLS) regression, geographically weighted regression (GWR) and structural equation modeling (SEM). Our results reveal that environmental and socioeconomic factors can explain most of the spatial variation of street tree quality in Washington, D.C. There is a substantial statistical negative relationship between median household income and the percent of street trees under stress, which provided the evidence of the inequities of street tree quality in Washington D.C. Higher-income neighborhoods exhibited a lower proportion of street trees under stress. In addition, the extreme summer temperature is positively associated with the proportion of street trees under stress. The quality of street trees is directly impacted by environmental and landscape pattern factors. There is also an indirect impact from socioeconomic factor toward quality of street trees. Our findings suggest that multiple variables, related to income, age, education, landscape pattern, and environment contribute to the quality of street trees in D.C. Based upon our findings, we identify strategies and insights for urban street tree management in DC to not only address environmental inequity and injustice, but also promote a more inclusive and resilient urban greenery system. 相似文献
8.
Vertical greenery systems (VGSs) have been adopted in city planning operations to mitigate excess heat in hot and humid subtropical cities. This study focused on the influence of different arrangements of vertical greening on pedestrian thermal comfort and particulate matter with a diameter of 10 µm (PM10) in street canyons. In this paper, the ENVI-met computational fluid dynamics (CFD) method was used to investigate the effects of different façade greenery arrangements with the same amount of greenery in the Nan Hai Yi Ku (NHYK) industrial district. On-site measurements were used to validate the simulation results in a transition season. The results showed that greening façades could improve pedestrians' thermal comfort with physiological equivalent temperature (PET) value reductions varying from 0.17 °C to 1.4 °C. Under a certain amount of greenery, the critical factor determining pedestrians' thermal comfort was the coverage rate of the greening façade near the pedestrian level. Specifically, increasing the greening façade coverage near the lower parts of street canyons could enhance the pedestrian-level cooling effect. In addition, the VGSs positively affected the pedestrian-level air quality in the street canyons. Nevertheless, the changes in pedestrian-level PM10 concentration induced by the presence of VGSs were not very obvious under the building-parallel wind direction. 相似文献
9.
为研究双孢菇的等级划分和自动化检测问题,设计了双孢蘑菇自动分级检测系统。通过对双孢菇图像的灰度化、二值化处理、预处理和图像分割,计算双孢菇菌盖直径大小,与国家分级标准进行对比,从而确定双孢菇的等级。该系统通过ARM控制器自动完成图像识别,具有识别准确率高、速度快的特点,提高双孢菇分拣的工作效率。 相似文献
10.
There is little information on the ecological composition of snow on roads as well as the toxic effect of de-icing salt on the ecological status of the street trees (Tilia x vulgaris H.) in Latvia. Tilia x vulgaris is one of the most widespread tree species of street greenery in the boreo-nemoral zone – in Central, Northern and Eastern Europe. This investigation was done to find out the accumulation of de-icing salt (main elements – sodium and chlorine) in the snow–soil–plant system of street greenery in the central part of Riga (2004–2005), in order to reveal the toxic effect on the ecological status of the street trees (Tilia x vulgaris). Snow, soil and leaf samples were collected from 27 study sites (eight objects) in the central part of Riga with intense traffic and from three control sites (one object) located in a park area. In a majority of cases, the status of street trees could be characterized as damaged. There was a high heterogeneity in the Na and Cl concentrations even along one street. Significantly, increased levels of Na and Cl in urban snow, soil and leaf samples were found in comparison with the background values. There was close correlation between the Na, Cl concentration in the leaves and the extent of leaf necrosis. Principal new information on the critical level for observation visual Tilia x vulgaris leaf necrosis was stated based on our results: 0.14% Na and 0.66% Cl concentrations in the leaves. 相似文献
11.
Street trees provide significant and widespread environmental benefits to the city and its citizens, such as improved air quality and adaptation to climate change. Crown volume (CV) indicates the geometric volume of crown, which is an essential indicator for the ecological service evaluation of street trees. The measurement of CV makes it possible to assess the carbon storage and input cost of urban trees. Because of the particularity of crown shape of street trees, the existing two-dimensional methods of calculating CV of forest trees become difficult except the three-dimensional techniques through the unmanned aerial vehicle, LiDAR equipment, and traditional harvest methods. In this study, a new virtual research method for plane calculation of angle disparity (PCAD) is proposed to calculate the CV of street trees. Two temporal satellite images of the exact location were first collected from Google Earth Pro, and then the angle disparity of images was adopted as a starting point to calculate tree height. Finally, CV was calculated from tree height, stem height, and crown diameter. The feasibility of the method was verified by a sample survey of street trees in Shanghai, China and the relative error of CV calculation by PCAD compared to that by field survey was 17.31 %. PCAD has the advantages of low-cost, quick operation, and suitability for a large area in studying CV of street trees. 相似文献
12.
A renewed importance in the urban vegetation segmentation task has been growing over the last years, mainly due to new urban planning and management projects, which require proper data on green spaces. Although multi-spectral sensors and complex systems for image acquisition that support this task are standard in some works, they show disadvantages in cost and spatial resolution. Unmanned aerial vehicles (UAV) offer an affordable alternative so that they can get high-quality images. Such images deliver some challenges for the urban vegetation segmentation job, such as the color dispersion that urban green spaces present, vegetation greenness, and lightning conditions, like those seen in related works that use the most advanced devices. In this research, a cartesian chromatic histogram-based algorithm is proposed for urban vegetation segmentation in UAV images. The developed method uses morphological operators to enable the reduction in histogram color discontinuities. The tests that were carried about over sample images resulted in accuracy up to 98 %, surpassing the state-of-the-art tested techniques. The results validated the robustness and the accuracy of the proposal against different conditions presented in study cases. 相似文献
13.
Street trees provide shade and increase human thermal comfort during hot summer. In this study, we investigated the spatial distribution of shade provision of street trees in Boston, Massachusetts. The sky view factor (SVF), which influences the solar radiation to the ground and affects human thermal comfort, was used to indicate the contribution of street trees on shade provision. Google Street View (GSV) panoramas were used to calculate the photographic method based SVF (SVFP), with the consideration of all kinds of obstructions within street canyons. A building height model was used to calculate the simulation based SVF (SVFs), with consideration of obstruction of building blocks only. Considering the fact that street trees and building blocks are the two major obstructions of radiation within street canyons, therefore, the difference between the two SVF estimation results can be considered as the shade provision of street trees. The results show that street trees help to decrease the SVF by 24.61% in Boston, Massachusetts. The shading level varies spatially in the study area. Generally, the southwestern area has much higher shading level than the north and the east. We further explored the shading variation among different socioeconomic groups in the study area. Result shows that Hispanics tend to live in neighborhoods with lower shading level. This study can help to provide a reference for future urban greening projects for global climate change adaption. 相似文献
14.
为实现蔬菜大棚内自动化除草的目的,针对其中的杂草识别环节,提出了一种基于三维点云的新型蔬菜大棚杂草识别方法。采用RGB-D相机获取青菜田、生菜田的三维点云图像,采用超绿色算法去除其中的土壤等背景,采用体素滤波法在保留点云图像形状特征的同时降低点云数量,然后采用欧式聚类法分割出单株青菜和单棵杂草的点云簇,分别计算得到每个点云簇的最高点的Z坐标值,最后结合深度信息Z坐标值实现蔬菜大棚杂草识别。结果表明:这种基于三维点云的杂草识别方法能够有效的识别出杂草,识别率为86.48%。该方法能够对蔬菜大棚中的杂草进行准确识别,为蔬菜大棚自动化除草提供有效的解决方案。 相似文献
15.
利用现代计算机技术,对20339份果树种质资源性状鉴定和评价数据进行规范化处理,建成了中国果树种质资源信息系统。该系统可在Zmin内检索和打印出用户所需果树种质资源的来源和主要性状,并对数据库中的各种数据总体特征进行统计分析。利用图形和图像技术建立了果树品种系谱溯源和追踪、染色体自动识别、同工酶电脑分析和果树种质资源电子地图系统,为进一步利用果树种质资源开展常规育种和生物技术育种提供了现代化分析工具。该系统于1995年12月在北京通过国家科委验收,井人了中国作物种质资源信息系统,正式投入运行,为果树种质资源研究人员、果树育种和果树生产人员提供多种形式的咨询服务。 相似文献
16.
Vegetation barriers have been widely applied along urban streets to improve roadside air quality. For a deep investigation of their influences, field measurements and numerical simulations are performed in this study. Carbon monoxide (CO) is selected as a representative of gaseous traffic emissions for both field observations and numerical models. Computational Fluid Dynamics (CFD) models of the standard k-ε turbulent model and Eulerian approach for species transport are solved by FLUENT solver. Results obtained from numerical simulations show a good agreement with field observations on the distribution of roadside CO. In perpendicular wind conditions, both field observations and numerical simulations present a prominent CO reduction over the slow lanes (footpath and bikeway) when vegetation barriers exist. To effectively mitigate roadside air pollution, numerical simulations also provide the optimal heights for roadside vegetation barriers in the given street canyons. For street canyons with an aspect ratio (the ratio of building height to street width) ranging from 0.3 to 1.67, 1.1 m can be used as an optimal height, and 2.0 m could serve as an alternative if tall vegetation barriers are considered. For street canyons with an aspect ratio of lower than 0.3, 0.9 m to 2.5 m can be considered as the optimal heights for roadside vegetation barriers. According to sensitivity analysis, the optimal heights for vegetation barriers are largely insensitive to wind velocities in the given street canyons. In the more complicated urban street canyons and complex meteorological conditions, the optimal heights can be determined by specific numerical simulations. These findings are expected to provide important insights into alleviation of gaseous mobile emissions in terms of vegetation barrier design in urban streets. 相似文献
17.
Urban areas face severe challenges in mitigating and adapting to climate change within limited space. One solution is to develop multifunctional rooftop systems, which use underexploited urban rooftop spaces. Two main options have been to add greenery by installing extensive green roofs (EGRs) or to generate renewable energy by installing photovoltaic panels (PVs). Recently, combining the two systems on one rooftop (EGR-PV) to harvest both benefits has gained attention. Not every rooftop is suitable for such installations, which makes it difficult to estimate the scale of space a city can expect from rooftops to add greenery, renewable energy, or both. This study presents a geographical potential model using building parameters, a building stock layer, and LiDAR data to simultaneously identify the potential for installing EGRs, PVs, and EGR-PVs on rooftops, highlighting the competition and synergy between EGRs and PVs at the building level. As an empirical illustration to support future multifunctional urban rooftop space planning, Amsterdam was used as a case study. The results show that 47 % of rooftops are suitable for EGRs, which could expand the current greenery space by 6 %, and 55 % are suitable for PVs which could sufficiently provide electricity to households by 2030. Moreover, competition exists for 3.2 %, whereas synergy exists for 42 % of the existing rooftops. 相似文献
18.
Liveability is an important component of the sustainable urban environment, especially in residential neighbourhoods. This study presents a comparison in perceived liveability between residents living in two very different locations, Tehran, Iran and Tartu, Estonia, using a questionnaire survey (n = 102). The image-questionnaire was used to measure residents’ response towards environmental factors and to examine the relationships between the attributes of residential neighbourhoods and perceived liveability. Statistical analyses were performed to analyze the data collected from the survey. The results showed that the neighbourhood liveability was positively influenced by proportion and scale of the spaces, amount of private green areas, street character, amount of public greenery, the variety of building form, the mix of buildings from different periods, perceived crowding and social density. The study demonstrated that residents can assess the factors and that the approach worked in two contrasting locations. The results also showed a great deal of similarity in preference, although this was not the main aim of the study. The approach has potential to be incorporated into participatory urban planning models. 相似文献
19.
Thi-Thanh-Hien Pham Philippe Apparicio Shawn Landry Anne-Marie Séguin Martin Gagnon 《Urban Forestry & Urban Greening》2013,12(1):18-27
Urban vegetation is shown to be unevenly distributed across cities and there is evidence of disparities in benefits provided by vegetation and of public health problems induced by urban heat islands. In order to improve vegetation cover, it remains crucial to understand the underpinning of such unevenness. In this paper, we investigate in Montreal (Canada) how the built environment, sociodemographic factors and administrative boroughs influence tree and lawn cover in public and residential land. The analysis was conducted at the dissemination area (DA) level, a Canadian census unit containing about 400–700 people. Six vegetation indicators were used as dependent variables: the proportion of a DA covered by trees/shrubs, lawn and total vegetation; the proportion of streets covered by trees/shrubs and the proportion of residential yards covered by trees/shrubs and total vegetation. Three sets of independent variables were studied: the built environment, sociodemographics and borough names. We used spatial autoregressive models to control for dependence and the spatial autoregressive term explained a large amount of variability in vegetation cover. The built-environment variables tend to have higher effects than the socio-demographic variables when predicting the three DA vegetation indicators, backyard vegetation, and to a lesser degree, street tree/shrub cover. In particular, population density is associated negatively to all indicators but positively to street tree cover. Socio-demographics are substantial in the explanation of the distribution of street trees, especially the presence of recent immigrants (negative effect) and of university degree holders (positive effect). These findings call for appropriate greening programs adapted to the local socio-demographic profile. The significance of boroughs also suggests the need for further research on the impact of within-city administrative hierarchies on the unevenness of urban vegetation. 相似文献
20.
To successfully use remotely-sensed data in landscape-level management, questions as to the relevance of image data to landscape
patterns and optimal scales of analysis must be addressed. Object-based image analysis, segmenting images into homogeneous
regions called objects, has been suggested for increasing accuracy of remotely-sensed products, but little research has gone
into determining image object size with regard to scaling of ecosystem properties. We looked at how segmentation of high-resolution
Ikonos and medium-resolution Landsat images into successively coarser objects affected multivariate correlations between image
data and eight percent-cover measurements of a sagebrush ecosystem. We also looked at changes in correlation as imagery was
aggregated into larger square pixels. We found similar canonical correlations between field and image data at the finest scales,
but higher for image segmentation than pixel aggregation for both images when scale increased. For image segmentation, correlations
between the canonical variables and original field variables were invariant with respect to size of the image objects, suggesting
linear scaling of vegetation cover in our study system. We detected a scaling threshold with the Ikonos segmentation and confirmed
with a semi-variogram of the sample data. Below the threshold interpretation of the canonical variables was consistent: scale
levels differed primarily in the amount of detail portrayed. Above the threshold, meaning of the canonical variables changed.
This approach proved useful for evaluating overall utility of images to address an objective, and identified scaling limits
for analysis. Selection of appropriate scale for analysis will ultimately depend on the objective being considered. 相似文献