Evaluation of Lot Shape for Automated System of Land Appraisal with Neural Networks

本研究的目的是开发一种评估过程中土地形状的方法：利用神经网络等方法开发评估函数，分析土地形状评估机制，开发土地评估的局部系统。今年作为项目的最后一年，我利用东京世田谷地区的地价详细数据库，对地价的评价函数进行了细化，得到了两个主要的结果。其中一组结果是基于地块形状、区位因素和环境因素的详细数据，估算出一个非常精确的享乐地价模型。该模型的意义在于它纳入了微观层面的居住环境，使我们能够从货币角度评估地块细分和公园配置的外部影响。特别是，根据地块的大小，绿化和混合使用的效果有不同的影响。土地面积越大，绿地效应越小，土地混合利用效应越大。该模型可用于区域规划中的城市规划/权利调整支持系统，并可用于求解最优街区划分问题。另一组结果涉及在评估过程中适当选择参考地段。实证结果表明，相对于享乐回归，合理选择参考地块能更准确地评估地价。这一结果证明了在评估过程中采用销售比较法是合理的。此外，研究结果还揭示了在评价中，参考地块应符合哪些因素：距离最近的火车站的距离、到中心城市的时间以及地块的形状（如转角地块和旗形）应尽可能均衡，以准确评价。

The aim of this research is to develop a method to evaluate the shape of lots in appraisal process: developing appraisal function using such as neural networks, analyzing the shape evaluation mechanism, and developing a partial system of land appraisal. This year as the final year of the project I refined evaluation function of land price using detailed database of land prices in Setagaya-ku in Tokyo, through which two major results have been obtained. One set of results is to estimate a very precise hedonic land price model of detailed data on lot shape, locational factors and environmental factors. Significance of the model lies in its incorporation of micro-level residential environment that enabled us to evaluate in monetary terms the external effects of subdivision of land parcels as well as allocation of parks. In particular, the effects of greenery and lend-use mixture have different influence depending on the size of the lot. For larger lots, the greenery effect is smaller, and the land-use mixture effect is larger. This model can be used to city planning/right adjustment supporting system in district planning, and can be applied to obtain optimal block division problems. The other set of results concerns the appropriate choice of reference lots in appraisal process. It was empirically shown that appropriate choice of reference lots enables us to evaluate the land price more precisely than a hedonic regression. This result justifies the sales comparative method in appraisal process. Moreover, the results revealed what kind of factors of reference lots should be conformed to the lot in evaluation: Distance to the nearest railway station, time to the central city, and shape of lots such as corner lot and flag shape should be equalized as much as possible for the precise appraisal.