A step-by-step illustrated guide documents the painstaking process of correcting the coastline of the Rann of Kutch in OpenStreetMap, where low-resolution satellite-derived data mistakenly rendered a seasonal salt marsh as ocean. The screenshots and code excerpts show how to edit connected `natural=coastline` ways in JOSM, ensuring proper segment direction and end-to-end linking to prevent catastrophic rendering errors that could invert entire continents. The example highlights the use of OpenStreetMap’s API, the Geofabrik OSMI coastline QA tool, and JOSM’s editing interface, alongside reference Landsat imagery for tidal line placement.