iosswiftcllocationmanagercatransaction

Move and Rotate GMSMarker smoothly along last updated GPS coordinates Swift iOS


I'm using GMSMapView. So I added custom GMSMarker and set the image(Ex. Bike image) and animating that marker when user starts moving and changing the angle of the marker in locationManager .

Currently I'm just updating position attribute of GMSMarker. But it gives the GMSMarker jump effect. Instead of this I want to move and rotate the GMSMarker smoothly/properly into the GMSMapView.

How can i achieve this in Swift? Thanks.

   (void)updateLocationoordinates(CLLocationCoordinate2D) coordinates
    { 
     if (marker == nil) {
      marker = [GMSMarker markerWithPosition:coordinates];
      marker.icon = [UIImage imageNamed:IMAGE];
      marker.map = mapView;
    } else{
     marker.position = coordinates; 
          }
    }  

Solution

  • I've faced the same problem and tried many ways. At last I've came up with a solution - to take angle between previous location point and present location point and I've used an UIImageView instead of GMSMarker.

    //in location update method
    CGPoint anglepoint = [myMapView.projection pointForCoordinate:currLocation.coordinate];
    CGFloat angle = [self getAngle:anglepoint];
    if(!isnan(angle)){
         [UIView beginAnimations:nil context:nil];
         [UIView setAnimationDuration:0.8f];
         sampleImgView.transform = CGAffineTransformMakeRotation(angle);
         [sampleImgView setCenter:[myMapView.projection pointForCoordinate:CLLocationCoordinate2DMake(currLocation.coordinate.latitude, currLocation.coordinate.longitude)]];
         [UIView commitAnimations];
         prevCurrLocation = currLocation;
    }
    
    
    -(CGFloat) getAngle: (CGPoint) touchedPoints
    {
        CGPoint previousLocationPoint = [myMapView.projection pointForCoordinate:prevCurrLocation.coordinate];
    
        CGFloat x1 = previousLocationPoint.x;
        CGFloat y1 = previousLocationPoint.y;
    
        CGFloat x2 = touchedPoints.x;
        CGFloat y2 = touchedPoints.y;
    
        CGFloat x3 = x1;
        CGFloat y3 = y2;
    
        CGFloat oppSide = sqrtf(((x2-x3)*(x2-x3)) + ((y2-y3)*(y2-y3)));
        CGFloat adjSide = sqrtf(((x1-x3)*(x1-x3)) + ((y1-y3)*(y1-y3)));
    
        CGFloat angle = atanf(oppSide/adjSide);
        // Quadrant Identifiaction
        if(x2 < previousLocationPoint.x)
        {
            angle = 0-angle;
        }
    
    
        if(y2 > previousLocationPoint.y)
        {
            angle = M_PI/2 + (M_PI/2 -angle);
        }
        return angle;
    }
    

    Use this for animation:

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.5f];
    sampleImgView.transform = CGAffineTransformMakeRotation(angle);
    [sampleImgView setCenter:[myMapView.projection pointForCoordinate:CLLocationCoordinate2DMake(currLocation.coordinate.latitude, currLocation.coordinate.longitude)]];
    [UIView commitAnimations];
    

    Here is the sample Imageview:

    sampleImgView = [[UIImageView alloc]init];
    sampleImgView.center = myMapView.center;
    sampleImgView.frame = CGRectMake(0,0, 25, 50);
    sampleImgView.backgroundColor = [UIColor clearColor];
    [myMapView addSubview:sampleImgView];
    

    Hope this helps.