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我有以下代码来计算 MKCoordinateRegion 以显示包含两个定义点的地图。问题是当经度超过 180 或 -180 度时它不起作用。

CLLocationCoordinate2D tempPoint1 = CLLocationCoordinate2DMake(startLat,startLong);
CLLocationCoordinate2D tempPoint2 = CLLocationCoordinate2DMake(nextLat,nextLong);

if (lineType == 1) {
    [self createGreatCircleMKPolylineFromPoint: tempPoint1 toPoint: tempPoint2 forMapView:mapView];
}
else  {
    CLLocationCoordinate2D *coords = malloc(sizeof(CLLocationCoordinate2D) * 2);
    coords[0] = tempPoint1;
    coords[1] = tempPoint2;

    MKPolyline *polyline = [MKPolyline polylineWithCoordinates:coords count:2];
    free(coords);
    [mapView addOverlay:polyline];

}

double lon1 = tempPoint1.longitude * M_PI / 180;
double lon2 = tempPoint2.longitude * M_PI / 180;

double lat1 = tempPoint1.latitude * M_PI / 180;
double lat2 = tempPoint2.latitude * M_PI / 180;

double dLon = lon2 - lon1;

double x = cos(lat2) * cos(dLon);
double y = cos(lat2) * sin(dLon);

double lat3 = atan2( sin(lat1) + sin(lat2), sqrt((cos(lat1) + x) * (cos(lat1) + x) + y * y) );
double lon3 = lon1 + atan2(y, cos(lat1) + x);

CLLocationCoordinate2D center;

center.latitude  = lat3 * 180 / M_PI;
center.longitude = lon3 * 180 / M_PI;


MKCoordinateSpan locationSpan;
locationSpan.latitudeDelta = fabs(tempPoint1.latitude - tempPoint2.latitude) * 1.2;
locationSpan.longitudeDelta = fabs(tempPoint1.longitude - tempPoint2.longitude) * 1.2;
MKCoordinateRegion region = {center, locationSpan};

[mapView setRegion:region];

任何想法我可以如何更改此代码以确保它可以处理 startLong 为正即 174 和 nextLong 为负即 -127，反之亦然

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1 回答 1

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和是经度的度数startLong，nextLong所以从 0° 到 360°，您可以确保它们都是正数和nextLong>= startLong：

while( startLong < 0.0 ) startLong += 360.0f;
while( startLong >= 360.0 ) startLong -= 360.0f;
while( nextLong < startLong ) nextLong += 360.0f;
while( nextLong - startLong > 360.0 ) nextLong -= 360.0;

有了这个，你确定：

  • startLong介于 0.0 和 360.0 之间（后者除外）
  • nextLong介于startLong和startLong+ 360.0之间
于 2015-05-06T13:30:55.627 回答