GPS定位坐标计算距离

 //算距离
           
CLLocation *currentLocation = [[[CLLocation
alloc] initWithLatitude:_nowLocation.latitude
longitude:_nowLocation.longitude]
autorelease];
           
CGFloat position_x = [[pBuinessDic
objectForKey:@"position_x"]
floatValue];
           
CGFloat position_y = [[pBuinessDic
objectForKey:@"position_y"]
floatValue];

            CLLocationCoordinate2D coor;
            coor.latitude = position_x;
            coor.longitude = position_y;
           
CLLocation *Location = [[[CLLocation
alloc] initWithLatitude:coor.latitude
longitude:coor.longitude]
autorelease];
           
CLLocationDistance distance = [currentLocation
distanceFromLocation:Location];
           
NSString *pDistanceStr =
@"";
           
if (distance<10)
            {
                pDistanceStr =
@"<10m";
            }
           
else if (distance<50)
            {
                pDistanceStr =
@"<50m";
            }
           
else if(distance<1000)
            {
                pDistanceStr = [NSString
stringWithFormat:@"%.0fm",distance];
            }
           
else if(distance>1000)
            {
                pDistanceStr = [NSString
stringWithFormat:@"%.1fkm",distance/1000];
            }