MMATWidth: Detection of River Centerlines Extraction and Width Estimation Using Modified Medial Axis Transform

Detecting River centerlines and estimating river widths are crucial in fluvial geomorphology. Extracting such information from satellite images enables an understanding of river network dynamics. The Medial Axis Transform (MAT) has several advantages over other centerline and width extraction methods. For example, it provides a compact geometrical representation of the shape and preserves topological properties, which benefits large datasets and complex river networks. This paper presents a practical approach that applies a Modified Medial Axis Transform (MMAT) to detect the centerline and width of the river. This method identifies the midpoints of the river's width, forming the centerline, and calculates the distance from this centerline to the river's edge, accurately measuring the river's width. The approach is effective and highly practical, as demonstrated by intensive experiments and case studies in the Sipsey River. It was tested using the reach scale of the Sipsey River with Sentinel-1A and validated with a higher-resolution satellite image from PlanetScope.