多源数据支持下的城市生态环境评价及其与人类活动的关系

Evaluation of Urban Ecological Environment and Its Relationship with Human Activities with Multi-source Data

  • 摘要: 探究城市生态环境与人类活动的关系,是目前城市化进程中的重要研究内容。结合多源数据,提出了采用兴趣点(point of interest,POI)、开放街道地图(OpenStreetMap,OSM)道路网、住宅区数据构建人类活动指标(住宅区可步行测度指数、街道活力指数、城市功能混合度指数)和利用遥感影像构建城市生态环境指标(遥感生态指数)的方法。并结合多项式回归(polynomial regression,PLR)、随机森林回归(random forest regression,RFR)、极限梯度提升回归(extreme gradient boosting regression,XGB)、支持向量回归机(support vector regression machine,SVR)等机器学习模型,对城市生态环境与人类活动指标进行回归分析。以中国江西省南昌市为例开展实例研究,结果显示:(1)人类活动的3项指标均呈现中心高,向四周逐渐递减的趋势,而城市生态环境指标则表现出相反的态势。(2)在探究城市生态环境与人类活动关系的研究中,XGB的效果最好。(3)街道活力指数、城市功能混合度指数与城市生态环境的相关性更强,住宅区可步行测度指数与城市生态环境的相关性更差。(4)在人类活动影响较小的区域,城市生态环境会受到其他因素的干扰导致预测结果精度不高,而在人类活动强烈的区域预测精度较高。

     

    Abstract:
      Objectives  To explore the relationship between urban ecological environment and human activities is an important research content in the current urbanization process. With the in-depth development of the era of big data, multi-source data ubiquitous in the Internet has been fully excavated, which has played an important role in promoting the research of urban ecological environment.
      Methods  Based on multisource data, we propose to construct human activity indicators (residential area walkability index, street vitality index, urban function mixing index) using point of interest(POI), OpenStreetMap (OSM) and residential area data, and urban ecological environment indicator (remote sensing ecological index)using remote sensing images. Combing machine learning models such as polynomial regression(PLR), random forest regression(RFR), extreme gradient boosting regression(XGB) and support vector regression machine(SVR), it is effective to make regression analysis on urban ecological environment and human activity indicators. By comparing the performance of different models in this dataset, the relationship between the urban ecological environment and human activities is revealed.
      Results  We demonstrate the application of our method using a case study of Nanchang city. The results show that: (1) The three indexes of human activities all present a central high and gradually decrease to the surroundings, while the urban ecological environment indicators show an opposite trend. (2) From the analysis of the performance results of each model on the dataset, XGB has the best regression effect, followed by PLR.(3)There is a strong negative correlation between the urban ecological environment and human activities, and the street vitality index, the urban function mixing index are more relevant to the urban ecological environment, and the walkability index of the residential area is less relevant to the urban ecological environment. (4) In areas where human activities have less impact, the urban ecological environment will be disturbed by other factors, resulting in the low prediction accuracy, while the prediction accuracy in areas with strong human activities is high.
      Conclusions  Using multisource data and machine learning models can provide an important reference for exploring the relationship between urban ecological environment and human activities.

     

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