public static List <MBR> ExtractRegions(List <GeoPoint> points)
{
List <MBR> regions = new List <MBR>();
// if (lat > 392600000 && lat < 410300000 && lng > 1152500000 && lng < 1173000000)
MBR mbr = new MBR(115.25, 39.26, 117.3, 41.03);
double cellSize = 500 * TrjTools.Constants.D_PER_M;
int minCount = 20;
GridPoint index = new GridPoint(points, mbr, cellSize);
regions = index.GetHotRegions(minCount);
return(regions);
}