Google Maps API V3 - 多邊形SMOOTHED邊緣

Question

是否可以平滑多邊形的線條/邊緣？它目前非常尖銳和有角度，如果這些角度實際上對他們有曲率，那將是非常好的。有任何想法嗎？

Answer 1

向您的多邊形中添加其他點。繪製的點越多，曲線越平緩。

Answer 2

這是基於B樣條平滑算法，通過https://johan.karlsteen.com/2011/07/30/improving-google-maps-polygons-with-b-splines/

public List<LatLng> bspline(List<LatLng> poly) { 

     if (poly.get(0).latitude != poly.get(poly.size()-1).latitude || poly.get(0).longitude != poly.get(poly.size()-1).longitude){ 
      poly.add(new LatLng(poly.get(0).latitude,poly.get(0).longitude)); 
     } 
     else{ 
      poly.remove(poly.size()-1); 
     } 
     poly.add(0,new LatLng(poly.get(poly.size()-1).latitude,poly.get(poly.size()-1).longitude)); 
     poly.add(new LatLng(poly.get(1).latitude,poly.get(1).longitude)); 

     Double[] lats = new Double[poly.size()]; 
     Double[] lons = new Double[poly.size()]; 

     for (int i=0;i<poly.size();i++){ 
      lats[i] = poly.get(i).latitude; 
      lons[i] = poly.get(i).longitude; 
     } 

     double ax, ay, bx, by, cx, cy, dx, dy, lat, lon; 
     float t; 
     int i; 
     List<LatLng> points = new ArrayList<>(); 
     // For every point 
     for (i = 2; i < lats.length - 2; i++) { 
      for (t = 0; t < 1; t += 0.2) { 
       ax = (-lats[i - 2] + 3 * lats[i - 1] - 3 * lats[i] + lats[i + 1])/6; 
       ay = (-lons[i - 2] + 3 * lons[i - 1] - 3 * lons[i] + lons[i + 1])/6; 
       bx = (lats[i - 2] - 2 * lats[i - 1] + lats[i])/2; 
       by = (lons[i - 2] - 2 * lons[i - 1] + lons[i])/2; 
       cx = (-lats[i - 2] + lats[i])/2; 
       cy = (-lons[i - 2] + lons[i])/2; 
       dx = (lats[i - 2] + 4 * lats[i - 1] + lats[i])/6; 
       dy = (lons[i - 2] + 4 * lons[i - 1] + lons[i])/6; 
       lat = ax * Math.pow(t + 0.1, 3) + bx * Math.pow(t + 0.1, 2) + cx * (t + 0.1) + dx; 
       lon = ay * Math.pow(t + 0.1, 3) + by * Math.pow(t + 0.1, 2) + cy * (t + 0.1) + dy; 
       points.add(new LatLng(lat, lon)); 
      } 
     } 
     return points; 

    }