我有一个由一组地理位置定义的区域,我需要知道一个坐标是否在这个区域内
public class Region{
List<Coordinate> boundary;
}
public class Coordinate{
private double latitude;
private double longitude;
}
public static boolean isInsideRegion(Region region,Coordinate coordinate){
}
解决方法
您可以应用
Computational Geometry问题中的
Point in polygon算法.
Paul Bourke用C语言编写了四种算法,你可以看到代码here.在Processing Forum中有一个对Java的改编,以防万一你不能使用Java7：
public class RegionUtil {
boolean coordinateInRegion(Region region,Coordinate coord) {
int i,j;
boolean isInside = false;
//create an array of coordinates from the region boundary list
Coordinate[] verts = (Coordinate)region.getBoundary().toArray(new Coordinate[region.size()]);
int sides = verts.length;
for (i = 0,j = sides - 1; i < sides; j = i++) {
//verifying if your coordinate is inside your region
if (
(
(
(verts[i].getLongitude() <= coord.getLongitude()) && (coord.getLongitude() < verts[j].getLongitude())
) || (
(verts[j].getLongitude() <= coord.getLongitude()) && (coord.getLongitude() < verts[i].getLongitude())
)
) &&
(coord.getLatitude() < (verts[j].getLatitude() - verts[i].getLatitude()) * (coord.getLongitude() - verts[i].getLongitude()) / (verts[j].getLongitude() - verts[i].getLongitude()) + verts[i].getLatitude())
) {
isInside = !isInside;
}
}
return isInside;
}
}
