如何在地图上的两点之间绘制箭头？地图套件

Question

如何在地图上的两点之间绘制箭头？
我尝试计算纬度和经度，但出了问题。

最诚挚的问候，麦克斯

这是我的代码和结果图

        int currpoints1 = 2;
    NSLog(@"!!!!!!!!%d ",numPoints);
    while(currpoints1 < numPoints)
    {

        TrackPoint* current = nil;
        CLLocationCoordinate2D* coordsArrrow = malloc((3) * sizeof(CLLocationCoordinate2D));
        for (int i =currpoints1, j=0; i < numPoints; i=i+1, j++)
        {
            current = [cashpoints objectAtIndex:i];
            coordsArrrow[j] = current.coordinate;
            if (i % 2 !=0) {
                int Gug = 30;

                int ug;
                float bx, by, ex, ey;
                bx = coordsArrrow[0].latitude;by = coordsArrrow[0].longitude;
                ex = coordsArrrow[1].latitude;ey = coordsArrrow[1].longitude;
                float Lstr = sqrt((ex-ey)*(ex-ey)+(bx-by)*(bx-by));
                ug = [self RetGradW:(abs(coordsArrrow[1].latitude-coordsArrrow[0].latitude)) height:abs(coordsArrrow[1].longitude-coordsArrrow[0].longitude)];
                ug = ug - Gug;
                coordsArrrow[0].latitude  = ex;
                coordsArrrow[0].longitude = ey;
                coordsArrrow[1].latitude  = ex+Lstr*cos(ug*M_PI/180);
                coordsArrrow[1].longitude = ey+Lstr*sin(ug*M_PI/180);
                ug=ug+2*Gug;
                coordsArrrow[2].latitude  = ex+Lstr*cos(ug*M_PI/180);
                coordsArrrow[2].longitude = ey+Lstr*sin(ug*M_PI/180);

                MKPolyline *points = [MKPolyline polylineWithCoordinates:coordsArrrow count:3];
                points.subtitle = @"arrow";
                [map addOverlay:points];
                break;
            }
        }
        free(coordsArrrow);
        currpoints1 = currpoints1 +14;
    }

enter image description here

Answer 1

您的箭头会改变角度，因为您没有在 viewForAnnotation 中正确重用它们。

只需为每个箭头创建一些唯一的 id，如下所示

viewForAnnotation

:

routeAnnotationView = (MKAnnotationView *)[lmapView dequeueReusableAnnotationViewWithIdentifier:[NSString stringWithFormat:@"%f%f",annotation.coordinate.latitude, annotation.coordinate.longitude]];

if (!routeAnnotationView)
{
    routeAnnotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:[NSString stringWithFormat:@"%f%f",annotation.coordinate.latitude, annotation.coordinate.longitude]];
    UIImage *image = [self rotateImage:[UIImage imageNamed:@"arrpix11.png"] onDegrees:RADIANS_TO_DEGREES(curAngle)+90];
    routeAnnotationView.image = image;
}
else
{
    routeAnnotationView.annotation = annotation;
}
routeAnnotationView.canShowCallout = NO;

Answer 2

我用其他方式改变了它。进行注释并在两点之间按方向旋转。

方法：

calculateDirection

：

int currpoints1 = 2;
NSLog(@"!!!!!!!!%d ",numPoints);
while(currpoints1 < numPoints)
{
    TrackPoint* current = nil;
    CLLocationCoordinate2D* coordsArrrow = malloc((2) * sizeof(CLLocationCoordinate2D));
    for (int i =currpoints1, j=0; i < numPoints; i=i+1, j++) {
        current = [cashpoints objectAtIndex:i];
        coordsArrrow[j] = current.coordinate;
        if (i % 2 !=0) {
            DirectAnnotation *placemark=[[DirectAnnotation alloc] initWithCoordinate: coordsArrrow[0]];
            
            CLLocationCoordinate2D coord1 = coordsArrrow[0];
            CLLocationCoordinate2D coord2 = coordsArrrow[1];
            
            CLLocationDegrees deltaLong = coord2.longitude - coord1.longitude;
            CLLocationDegrees yComponent = sin(deltaLong) * cos(coord2.latitude);
            CLLocationDegrees xComponent = (cos(coord1.latitude) * sin(coord2.latitude)) - (sin(coord1.latitude) * cos(coord2.latitude) * cos(deltaLong));
            
            CLLocationDegrees radians = atan2(yComponent, xComponent);
            CLLocationDegrees degrees = radiansToDegrees(radians) + 360;
            
            self.dir =  fmod(degrees, 360);
            
            NSLog(@"%f,%f %f,%f",coordsArrrow[0].latitude,coordsArrrow[0].longitude,coordsArrrow[1].latitude,coordsArrrow[1].longitude);
            [self.map addAnnotation:placemark];
            break;
        }
    }
    free(coordsArrrow);
    currpoints1 = currpoints1 +14;
}

和

annotation

：

- (MKAnnotationView *)mapView:(MKMapView *)mV viewForAnnotation:(id <MKAnnotation>)annotation{
    if ([annotation isKindOfClass:[DirectAnnotation class]]) {
        arrow=[[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"parkingloc"];
        arrow.image = [UIImage imageNamed:@"userLocationCompass.png"];
        CGAffineTransform transform = CGAffineTransformMakeRotation(degreesToRadians(dir));
        arrow.transform = transform;
        return arrow;
    }else {
        return nil;
    }
}

但是我仍然面临一些问题，

缩放前：

enter image description here