OtsuSeg: an R package implementing Otsu’s thresholding technique for mapping forest fire scars with integrated accuracy assessment
摘要
Although R offers a powerful environment for remote sensing analysis, it still lacks dedicated tools for the automated mapping of forest fire scars. To address this gap, we introduce OtsuSeg, an open-source R package that implements Otsu’s global thresholding algorithm for unsupervised burn scar segmentation and includes routines to assess classification accuracy using standard performance metrics. The package is designed to process pre- and post-fire optical imagery (Landsat, Sentinel-2) and streamline the extraction and evaluation of fire-affected areas. We applied OtsuSeg to four recent wildfire events in Tunisia and Algeria, validating the outputs against high-resolution reference perimeters from the Copernicus Emergency Management Service (EMS) Rapid Mapping. The results demonstrate that OtsuSeg consistently achieves high performance, with F1-scores exceeding 0.85 across all test cases. Moreover, a direct comparison with the binary thresholding tool in ArcGIS Pro—also based on Otsu’s method—revealed comparable accuracy, while highlighting OtsuSeg’s advantages in transparency, reproducibility, and accessibility. Beyond its practical utility for operational fire mapping, OtsuSeg also serves as an educational and research-oriented tool, offering a cost-effective solution for environmental monitoring and spatial data analysis.