HOTA: Hierarchical Overlap-Tiling Aggregation for Large-Area 3D Flood Mapping

Fuente: arXiv
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Autori principali: Jia, Wenfeng, Liang, Bin, Lu, Yuxi, Wilaiwongsakul, Attavit, Khan, Muhammad Arif, Zheng, Lihong
Natura: Preprint
Pubblicazione: 2025
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author Jia, Wenfeng
Liang, Bin
Lu, Yuxi
Wilaiwongsakul, Attavit
Khan, Muhammad Arif
Zheng, Lihong
author_facet Jia, Wenfeng
Liang, Bin
Lu, Yuxi
Wilaiwongsakul, Attavit
Khan, Muhammad Arif
Zheng, Lihong
contents Floods are among the most frequent natural hazards and cause significant social and economic damage. Timely, large-scale information on flood extent and depth is essential for disaster response; however, existing products often trade spatial detail for coverage or ignore flood depth altogether. To bridge this gap, this work presents HOTA: Hierarchical Overlap-Tiling Aggregation, a plug-and-play, multi-scale inference strategy. When combined with SegFormer and a dual-constraint depth estimation module, this approach forms a complete 3D flood-mapping pipeline. HOTA applies overlapping tiles of different sizes to multispectral Sentinel-2 images only during inference, enabling the SegFormer model to capture both local features and kilometre-scale inundation without changing the network weights or retraining. The subsequent depth module is based on a digital elevation model (DEM) differencing method, which refines the 2D mask and estimates flood depth by enforcing (i) zero depth along the flood boundary and (ii) near-constant flood volume with respect to the DEM. A case study on the March 2021 Kempsey (Australia) flood shows that HOTA, when coupled with SegFormer, improves IoU from 73\% (U-Net baseline) to 84\%. The resulting 3D surface achieves a mean absolute boundary error of less than 0.5 m. These results demonstrate that HOTA can produce accurate, large-area 3D flood maps suitable for rapid disaster response.
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id arxiv_https___arxiv_org_abs_2507_07585
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle HOTA: Hierarchical Overlap-Tiling Aggregation for Large-Area 3D Flood Mapping
Jia, Wenfeng
Liang, Bin
Lu, Yuxi
Wilaiwongsakul, Attavit
Khan, Muhammad Arif
Zheng, Lihong
Computer Vision and Pattern Recognition
Image and Video Processing
Floods are among the most frequent natural hazards and cause significant social and economic damage. Timely, large-scale information on flood extent and depth is essential for disaster response; however, existing products often trade spatial detail for coverage or ignore flood depth altogether. To bridge this gap, this work presents HOTA: Hierarchical Overlap-Tiling Aggregation, a plug-and-play, multi-scale inference strategy. When combined with SegFormer and a dual-constraint depth estimation module, this approach forms a complete 3D flood-mapping pipeline. HOTA applies overlapping tiles of different sizes to multispectral Sentinel-2 images only during inference, enabling the SegFormer model to capture both local features and kilometre-scale inundation without changing the network weights or retraining. The subsequent depth module is based on a digital elevation model (DEM) differencing method, which refines the 2D mask and estimates flood depth by enforcing (i) zero depth along the flood boundary and (ii) near-constant flood volume with respect to the DEM. A case study on the March 2021 Kempsey (Australia) flood shows that HOTA, when coupled with SegFormer, improves IoU from 73\% (U-Net baseline) to 84\%. The resulting 3D surface achieves a mean absolute boundary error of less than 0.5 m. These results demonstrate that HOTA can produce accurate, large-area 3D flood maps suitable for rapid disaster response.
title HOTA: Hierarchical Overlap-Tiling Aggregation for Large-Area 3D Flood Mapping
topic Computer Vision and Pattern Recognition
Image and Video Processing
url https://arxiv.org/abs/2507.07585