农村宅基地整治潜力的空间显式测算与模拟

    Spatially explicit calculation and simulation of estimating housing land consolidation potential in rural areas

    • 摘要: 把握农民拆旧整治意愿是准确估计农村宅基地整治潜力的基本前提。现有的农村宅基地整治潜力测算模型在农民拆旧整治意愿建模和潜力空间显式测算表达方面依然存在一定局限性。该研究尝试利用机器学习算法和土地利用多源时空数据,研究面向区域农村宅基地整治潜力测算的农民拆旧整治意愿模拟模型,实现农村宅基地整治潜力的空间显式估算。研究首先利用高分遥感和土地利用数据,提取以废旧建筑物为主的拆旧潜力区;在此基础上,利用单分类支持向量机算法和区域拆旧整治历史样本对区域农民群体的拆旧整治意愿进行模拟,从而实现区域宅基地拆旧整治潜力的空间显式测算。研究选取广东信宜市平塘镇作为研究区对模型的性能进行了验证和评估。结果表明,模型的总体模拟精度达96.36%,其中正向样本模拟精度为96.88%,负向样本模拟精度为80.14%。根据模型预测结果,平塘镇实际可供整治的废旧宅基地面积约为36.02 hm2,占平塘镇废旧宅基地总面积的34.65%。研究结果将为中国正在实施的全域土地综合整治和国土空间规划决策提供重要的决策依据。

       

      Abstract: Abstract: Modeling of farmers' willingness to consolidation of abandoned homesteads plays an essential role in the prediction of regional land consolidation potential. Previous prediction models on land consolidation potential still have some limitations in the simulation of farmers' consolidation willingness and the spatial explicit prediction. The complex system modeling and machine learning provide effective tools for the behaviors simulation of land-use stakeholders. Land consolidation potential depends mainly on the farmers' willingness to consolidation, as well as the policies and land use planning. It is difficult to obtain enough negative training samples from the non-reclaimed area where farmers are opposed to the consolidation. There is a balance on the training samples, meaning that most training samples are positive. One-class classification approach has provided a good solution for the classification of imbalanced samples, due to only positive samples is selected to complete the training of classifiers. Hence, one-class classification can be used to solve the negative samples in the modeling of farmers' willingness to land consolidation. Therefore, an one class support vector machine (OCSVM) was selected to simulate the decision-making behaviors of the farmers. The OCSVM has been widely used as a type of one-class classification in image recognition and abnormal detection. A geographic information system (GIS) was used to build the model, in order to predict the land consolidation potential in a spatially explicit way. Furthermore, high-resolution remote sensing images were used to identify the abandoned homesteads in the study region. Pingtang was selected as the study area to evaluate the accuracy of model, where a mountainous and poverty town located in western Guangdong province, China. 4 449 positive samples were obtained, where the farmers would like to confer from the historical land consolidation project data in the study area. Another 141 negative samples were randomly selected from the non-reclaimed areas to evaluate the accuracy of model. Thus, a total of 4 590 unlabeled samples were obtained to train the model. The experimental results showed that the overall accuracy of model reached 96.36%, the prediction accuracy of positive sample was 96.88%, and the accuracy of negative samples was 80.14%, indicating that the performance of model was reliable for the potential prediction of land consolidation. The model was used to predict the land consolidation potential in the whole study area. The total area of abandoned homesteads identified by high-resolution remote sensing images was about 103.96 hm2, whereas, the predicted potential obtained by the model was about 94.74 hm2. However, there were many small spots in the study area that were too fragmented to be reclaimed. According to the land consolidation of Pingtang, the abandoned homesteads that can be reclaimed was only 36.02 hm2, accounting for 34.65% of the total areas. Consequently, terrain factors were also essential to affect the consolidation potential in mountainous and hilly areas. The model can be expected to better support the decision-making of land use planning, regional land remediation planning, and site selection in land remediation project.

       

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