使用基于直方图的光谱判别法对印度韦洛尔市进行的案例研究--城市绿地可用性的区级计算是否重要?

IF 2.4 Q3 ENVIRONMENTAL SCIENCES
Sangeetha Gaikadi, S. V. Kumar
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引用次数: 0

摘要

个人有多少绿地是城市规划者普遍关心的一个重要问题,本研究旨在通过两种方法,即人均方法和地理区域方法,在印度韦洛尔的背景下解决这一问题。在现有的研究中,城市绿地(UGS)只在宏观层面上进行计算,即对整个城市进行计算。本研究也进行了同样的分析,以清楚地了解城市中每个区的可用绿地数量。为此,本研究提出了一种分两步走的方法,首先分析谷歌地球(GE)图像的直方图,检查树木、灌木/草地和耕地等绿色覆盖类型是否存在光谱差异。然后,将 ISODATA、最大似然法、支持向量机(SVM)和基于对象的方法等分类技术应用于 GE 图像。结果发现,SVM 在提取不同绿色植被类型方面表现出色,总体准确率最高,达到 93%,Kappa 系数为 0.881。研究发现,从整个城市来看,可用的 UGS 数量占总面积的 42%,超过了 20-40% 的建议范围。同样,人均可利用的 UGS 为 97.84 平方米,远高于建议的 12 平方米/人。然而,微观层面的分析表明,尽管整个城市满足了人均和百分比面积的标准,但有些区却没有满足这两个标准。因此,这些结果表明,在选区层面而非城市层面计算城市绿地可用性非常重要,因为前者能更近距离地观察过剩和不足区域。对单棵树木进行的地面激光雷达调查结果显示,如果树木紧邻建筑物或道路,则与没有树木的情况相比,热岛较少。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Is ward-level calculation of urban green space availability important?—A case study on Vellore city, India, using the histogram-based spectral discrimination approach
How much green space is available for individuals is a major question that city planners are generally interested in, and the present study aimed to address this issue in the context of Vellore, India, through two approaches, namely, the per capita and the geographical area approach. In existing studies, urban green space (UGS) was only calculated at the macro level, i.e., for the city as a whole. Micro-or ward-level analysis was not attempted before, and the present study carried out the same to get a clear picture of the amount of greenery available in each ward of a city. For this purpose, a two-step approach was proposed where the histograms of Google Earth (GE) images were analyzed first to check whether the green cover types such as trees, shrubs/grassland, and cropland were spectrally different. Then, classification techniques such as ISODATA, maximum likelihood, support vector machine (SVM), and object-based methods were applied to the GE images. It was found that SVM performed well in extracting different green cover types with the highest overall accuracy of 93% and Kappa coefficient of 0.881. It was found that when considering the city as a whole, the amount of UGS available is 42% of the total area, which is more than the recommended range of 20–40%. Similarly, the available UGS per person is 97.84 m2, which is far above the recommended 12 m2/person. However, the micro-level analysis revealed that some of the wards have not satisfied the criteria of per capita and percentage area, though the city as a whole has satisfied both the criteria. Thus, the results indicate the importance of calculating the urban green space availability at the ward level rather than the city level as the former gives a closer look at the surplus and deficit areas. The results of terrestrial LiDAR survey at individual tree level revealed that if trees are located adjacent to buildings or roads, it results in fewer heat islands compared to the case where there are no trees.
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来源期刊
CiteScore
4.00
自引率
7.10%
发文量
176
审稿时长
13 weeks
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