Google Maps for iOS - How can you tell if a marker is within the bounds of the screen?

Question

I'm trying to figure out a straightforward way to determine in Google Maps for iOS if a given GMSMarker is within the bounds of the visible map. There seems to be solutions for this in the Javascript API but other than perhaps doing some complex reasoning based on this post there doesn't seem to be a way.

score 17 · Answer 1 · answered May 06 '15 at 16:49

17

A code example based on Andy's helpful response:

- (void)snapToMarkerIfItIsOutsideViewport:(GMSMarker *)m{
    GMSVisibleRegion region = _mapView.projection.visibleRegion;
    GMSCoordinateBounds *bounds = [[GMSCoordinateBounds alloc] initWithRegion:region];
    if (![bounds containsCoordinate:m.position]){
        GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:m.position.latitude
                                              longitude:m.position.longitude
                                                   zoom:_mapView.camera.zoom];
        [self.mapView animateToCameraPosition: camera];
    }
}

answered May 06 '15 at 16:49

Dave Cole

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Thanks a lot! it works perfectly! saves me a lot of time – youssman Dec 29 '15 at 19:31
What will it return if my marker is half inside the region and half is outside? Actually I want to check if my marker is fully inside the region or not. How can I check that? – Nimisha Patel Apr 04 '18 at 16:47
Well, strictly speaking, your marker is a point, so it doesn't have dimensions. If your aim is to make sure that the graphic image you've associated with your marker is fully visible, I recommend iterating on this conditional, zooming out until it's satisfied, then zooming out one level more from that. – Dave Cole Apr 04 '18 at 17:15

score 14 · Accepted Answer · answered May 06 '15 at 15:50

14

Retrieve the bounds of your viewport with GMSVisibleRegion and create a GMSCoordinateBounds with it. Call containsCoordinate, passing in the marker's position. It should return true if the marker is within the viewport and false if not.

answered May 06 '15 at 15:50

Andy

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Gabriel Wamunyu · Answer 3 · 2019-10-03T17:08:20.573

10

The swift 4 version of the answer. Returning a boolean if marker is within the screen region or not

func isMarkerWithinScreen(marker: GMSMarker) -> Bool {
    let region = self.mapView.projection.visibleRegion()
    let bounds = GMSCoordinateBounds(region: region)
    return bounds.contains(marker.position)
}

edited Oct 03 '19 at 17:08

answered Feb 18 '18 at 02:00

Gabriel Wamunyu

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score 1 · Answer 4 · answered Nov 02 '17 at 06:20

I have written on method to find GMSMarker is in particular frame. Set your rectangle frame (x,y,maxX,maxY). You can set any frame from screen it tell find marker is in that frame or not..

- (BOOL)isGoogleMapMarkerVisible:(GMSMarker*)marker {

    //Marker point
    CGPoint markerpoint = [self.mapview.projection pointForCoordinate:marker.position];

    //Maximum visible region from x and y axis
    float x = 0.0;
    float y = o.o;
    float maxX = self.mapview.frame.size.width;
    float maxY = self.mapview.frame.size.height;

    //If marker point is on visible region return true else return false
    if (markerpoint.x > x && markerpoint.y > y && markerpoint.x < maxX && markerpoint.y < maxY) {
        return YES;
    }
    else {
            return NO;
    }
}

score 0 · Answer 5 · answered Aug 08 '16 at 10:07

Hope this code may help to code hunters.

NSMutableArray *mutArrMarkers; //Have all markers added on Map
.
.
.
.

NSMutableArray *mutArrMarkersInPath = [NSMutableArray array];
[mutArrMarkers enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
   GMSMarker *marker = obj;
   if(GMSGeometryContainsLocation(currentCoordinates, pathToCheck, YES)){
        [mutArrMarkersInPath addObject:marker];
   }
}];

Google Maps for iOS - How can you tell if a marker is within the bounds of the screen?

5 Answers5

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