Simplify, smooth and dissolve

• Set simplify tolerance in coordinate units, where 0.001 degrees is roughly 100 meters.
• Enable highQuality: true on turf.simplify for display lines that must not self-intersect.
• Call turf.dissolve(fc, { propertyName: 'zone' }) to merge adjacent polygons sharing that value.

var track = turf.lineString([/* 几千个顶点 */]);

console.log('原始顶点', track.geometry.coordinates.length);

var coarse = turf.simplify(track, {
  tolerance: 0.001,        // 约 100 米
  highQuality: true        // 更接近原始形状，代价是更慢
});

console.log('简化后', coarse.geometry.coordinates.length);

var rough = turf.simplify(track, { tolerance: 0.01 });
console.log('更粗', rough.geometry.coordinates.length);

var smooth = turf.bezierSpline(track, {
  resolution: 20000,       // 采样间隔，值越小点越密
  sharpness: 0.85          // 0 到 1，越大越贴近原折线
});

console.log(turf.length(smooth, { units: 'kilometers' }).toFixed(3));

• Computing area after simplify reports a changed value, so measure before simplifying.
• Faces that only look adjacent fail to dissolve until cleanCoords or snapping removes the gaps.