/**
 * A d3-geo path made fit for a thick line: simpler to within `toleranceMm`, loops whose longest side is under `minLoopMm` left out, corners rounded.
 * @param d - The path as d3-geo's `geoPath` writes it, in millimetres.
 * @param toleranceMm - How far the simpler line may stray from the real one.
 * @param minLoopMm - The smallest island, by its longest side, that is kept.
 * @returns The path.
 *
 * @example
 * ```ts
 * import { thickPath } from "@johnmorrisdotca/chikyu-earth/sheets";
 *
 * console.log(thickPath("M0,0L5,0.1L10,0L20,0", 0.5, 0));
 * ```
 */
export declare function thickPath(d: string, toleranceMm: number, minLoopMm: number): string;