Keep Map Target While Zooming To Show All Markers

13 Dec 2014

Recently an app I develop needed to keep the map center while zooming in/out to show all markers dropped on the map. It’s not a particularly difficult thing to do, but it took a moments thought. The example is for Android, but it works the same way on iOS etc.

LatLngBounds.Builder builder = new LatLngBounds.Builder(); for (Marker marker : markers) { builder.include(marker.getPosition()); } LatLngBounds bounds = builder.build(); LatLng currentLoc = _googleMapView.getCameraPosition().target; //make sure that centre location doesn't change double deltaLat = Math.max(Math.abs(bounds.southwest.latitude - currentLoc.latitude), Math.abs(bounds.northeast.latitude - currentLoc.latitude)); double deltaLon = Math.max(Math.abs(bounds.southwest.longitude - currentLoc.longitude), Math.abs(bounds.northeast.longitude - currentLoc.longitude)); LatLngBounds.Builder displayBuilder = new LatLngBounds.Builder(); displayBuilder.include(currentLoc); //not necessary but hey displayBuilder.include(new LatLng(currentLoc.latitude + deltaLat, currentLoc.longitude + deltaLon)); displayBuilder.include(new LatLng(currentLoc.latitude - deltaLat, currentLoc.longitude - deltaLon)); _googleMapView.moveCamera(CameraUpdateFactory.newLatLngBounds(displayBuilder.build(), 0));