Thota Sai Durga Malleswarさんの研究成果がJournal of Geovisualization and Spatial Analysisに掲載されました

2025.02.21

SyDE院生のThota Sai Durga Malleswarさん（理学研究科・地学専攻・D3）の研究成果がJournal of Geovisualization and Spatial Analysisに掲載されました。

【論文概要】

The box-counting method is the predominant technique for calculating fractal dimensions (FD) for raster data. While fields like image analysis have advanced with methods such as differential box-counting (DBC) to measure the FD of 3D surfaces, this approach has yet to be applied to geographical raster data. In this study, we particularly focus on selecting an appropriate box height, a methodological issue even for images. The difficulties in DBC, such as box height problems that appear in the log-log plots, were explained. We proposed key modifications to the conventional DBC method theoretically to reduce the number of inappropriate scales due to the difficulties in DBC. To identify the effective scales in log-log plots, we introduced a novel visualization technique that can detect subtle variations in log-log plots by visual inspection, aiding in identifying box height problems and related difficulties. We applied and compared the conventional and modified DBC method to two empirical datasets, population data and digital elevation model data, across the USA. Our results demonstrate that the log-log plots display greater consistency, and the FD values converge to a larger value as the box height decreases. Based on the empirical results, we proposed a derived method that eliminates the need to select a specific box height, addressing all three DBC difficulties identified in this study. Since the derived method no longer uses the ceiling function and does not count boxes, the acronym DBC should now stand for differential bar accumulation. This work attempts to serve as a tool for analysing geographical phenomena primarily using affordable raster data.

ジャーナル名：Journal of Geovisualization and Spatial Analysis

論文タイトル：Box Height-Independent Differential Bar Cumulation (DBC) for 3D Raster Surface Fractal Dimension Analysis

掲載日：2025/2/18

著者：S. D. Malleswar, Yuzuru Isoda, Tomoki Nakaya

DOI： https://doi.org/10.1007/s41651-025-00216-5