Digital maps often use a sharp line to show the edge of a wetland. On the ground, however, the boundary may shift with rainfall and season. A precise-looking border can encourage a builder to treat land just outside it as permanently dry. The mapmaker faces a choice. Drawing a wider band may seem less exact, but it can represent the range within which the boundary moves. The band does not mean that every point inside it is wet at every moment. It communicates variation that a single line conceals. Precision in appearance and faithfulness to a changing reality are therefore not identical. A responsible representation makes uncertainty legible without surrendering useful distinctions. The aim is not to avoid drawing boundaries but to prevent the neatness of a symbol from being mistaken for the stability of the thing it describes.