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我試圖計算Oracle數據庫中的兩個點之間的距離,如何使用Oracle的sdo_distance
Point A is 40.716715, -74.033907
Point B is 40.716300, -74.033900
使用這個SQL語句:
SELECT sdo_geom.sdo_distance(sdo_geom.sdo_geometry(2001 ,8307 ,sdo_geom.sdo_point_type(40.716715, -74.033907 , NULL) ,NULL ,NULL)
,sdo_geom.sdo_geometry(2001 ,8307 ,sdo_point_type(40.716300,-74.033901, NULL) ,NULL ,NULL) ,0.0001 ,'unit=M') distance_in_m
from DUAL;
結果是12.7646185977151
在使用Apple CoreLocation API時:
CLLocation* pa = [[CLLocation alloc] initWithLatitude:40.716715 longitude:-74.033907];
CLLocation* pa2 = [[CLLocation alloc] initWithLatitude:40.716300 longitude:-74.033900];
CLLocationDistance dist = [pa distanceFromLocation:pa2];
結果是46.0888946842423
自己實現
double dinstance_m(double lat1, double long1, double lat2, double long2){
double dlong = (long2 - long1) * d2r;
double dlat = (lat2 - lat1) * d2r;
double a = pow(sin(dlat/2.0), 2) + cos(lat1*d2r) * cos(lat2*d2r) * pow(sin(dlong/2.0), 2);
double c = 2 * atan2(sqrt(a), sqrt(1-a));
double d = 6367 * c;
return d * 1000.;
}
結果是46.120690774231
Oracle的實現顯然是關閉的,但我不明白爲什麼。任何幫助將不勝感激。