How to find zoom level based on circle draw on map

Question

I am drawing the circle on map with specifying the radius and it'll draw the circle successfully. But when I change the size of circle using seekbar I need to feet the circle in screen and zoom the map of that level, I have not idea about this, need your guideline thank you.

If it was the Javascript API you could do map.fitBounds(myCircle.getBounds()); but I don't know if the same functionality is available in Android. — Marcelo, Jul 03 '12 at 11:42
It's android I have specify the tag here, and I know about that and also know the spantozoom() available in android. but I have single point this method not usable, if I find the latlng from center point to radius distance any latlng then this method is useful — Pratik, Jul 03 '12 at 12:10
Pls find my solution on it. I did the same in one of my project. thanks — Rajneesh Shukla, Mar 26 '19 at 02:24

score 24 · Answer 1 · answered Dec 26 '14 at 08:16

24

We can also get the zoom level for map from the drawn circle

Circle circle = googleMap.addCircle(circleOptions);

googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
                        circleOptions.getCenter(), getZoomLevel(circle)

// Methode for zoomlevel

public int getZoomLevel(Circle circle) {
    int zoomLevel = 11;
    if (circle != null) {
        double radius = circle.getRadius() + circle.getRadius() / 2;
        double scale = radius / 500;
        zoomLevel = (int) (16 - Math.log(scale) / Math.log(2));
    }
    return zoomLevel;
}

answered Dec 26 '14 at 08:16

Anand Tiwari

1,583
10
22

Perfect solution! Thank you @Anand Tiwari – Matan Dahan Apr 09 '17 at 14:46
6

@AnandTiwari Works almost perfect, for some values I get 90% of the circle in. Can you explain the `/ 500` and the `16 -`? – ilomambo Oct 05 '17 at 06:22
Works perfect! Thanks a lot for the solution. – Abhi Apr 30 '18 at 10:03
do you know what the 500 stands for ? what does it mean to scale by 500 ? – j2emanue Sep 02 '19 at 08:30
This function is on the path towards the right answer, but it's composed onto magic numbers. There must be a mathematical explanation. This worked for me but I had to (obviously) change `zoomLevel` and `scale` accordingly. – venir Mar 02 '23 at 14:58

score 3 · Answer 2 · answered Jul 15 '18 at 13:58

build.gradle:

dependencies {
    compile 'com.google.maps.android:android-maps-utils:0.4+'
}

public static LatLngBounds getLatLngBoundsFromCircle(Circle circle){
    if(circle != null){
        return new LatLngBounds.Builder()
                .include(SphericalUtil.computeOffset(circle.getCenter(), circle.getRadius() * Math.sqrt(2), 45))
                .include(SphericalUtil.computeOffset(circle.getCenter(), circle.getRadius() * Math.sqrt(2), 225))
                .build();
    }
    return null;
}

map.animateCamera( CameraUpdateFactory
    .newLatLngBounds(MapUtils.getLatLngBoundsFromCircle(mapCircle),20) );

score 1 · Accepted Answer · answered Aug 03 '12 at 11:32

After long time I found the solution from somewhere.

here is the method which was giving me the min lat/lng and max lat/lng. Based on this I have getting the latspan and longspan.

public void boundingCoordinates(double distance, double radius) {

    if (radius < 0d || distance < 0d)
        throw new IllegalArgumentException();

    // angular distance in radians on a great circle
    double radDist = distance / radius;

    double radLat = Math.toRadians(gp.getLatitudeE6()/1e6); // here is your single point latitude gp.getLatitude
    double radLon = Math.toRadians(gp.getLongitudeE6()/1e6); // here is your single point longitude gp.getlongitude

    double minLat = radLat - radDist;
    double maxLat = radLat + radDist;

    double minLon, maxLon;
    if (minLat > MIN_LAT && maxLat < MAX_LAT) {
        double deltaLon = Math.asin(Math.sin(radDist) /Math.cos(radLat));
        minLon = radLon - deltaLon;

        if (minLon < MIN_LON) 
            minLon += 2d * Math.PI;

        maxLon = radLon + deltaLon;

        if (maxLon > MAX_LON) 
            maxLon -= 2d * Math.PI;
    } else {
        // a pole is within the distance
        minLat = Math.max(minLat, MIN_LAT);
        maxLat = Math.min(maxLat, MAX_LAT);
        minLon = MIN_LON;
        maxLon = MAX_LON;
    }

    minLat = Math.toDegrees(minLat);
    minLon = Math.toDegrees(minLon);
    maxLat = Math.toDegrees(maxLat);
    maxLon = Math.toDegrees(maxLon);

    minGeo = new GeoPoint((int)(minLat*1e6),(int)(minLon*1e6));
    maxGeo = new GeoPoint((int)(maxLat*1e6),(int)(maxLon*1e6));
}

now you pass the distance in any unit as per that you have to pass the radius of earth for example if you pass 2 km then the radius of earth is in km say 6370.997.

you can try it, its cool thing

Thanks for the code. but what is the use of minGeo and maxGeo? how may i zoom map view and fit circle — Asanka Senavirathna, Jan 30 '13 at 09:53
minGeo and maxGeo was used for minimum/maximum latitude and longitude value through this you can get the span latitude and longitude value for passing in zoomToSpan method using mapControl object — Pratik, Jan 30 '13 at 10:02

score 0 · Answer 4 · answered Mar 26 '19 at 02:23

In my code I am adding a transparent circle around a marker which has dynamic radius and zooming the map camera so it fit to screen.

it is working 100% fine in my project.

@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    mMap.setOnMarkerClickListener(this);

    MapsInitializer.initialize(Objects.requireNonNull(getContext()));

    // Add a marker on Property location
    LatLng propertyLatlng = new LatLng(getLatitude(), getLongitude());

    //  draw transparent blue circle around marker
    try {
        CircleOptions circleOptions = new CircleOptions()
                .center(propertyLatlng)
                .radius(Double.parseDouble(radius) / 0.00062137)
                .strokeColor(BLUE_TRANSPARENT)
                .strokeWidth(0)
                .fillColor(BLUE_TRANSPARENT);
        Circle circle = mMap.addCircle(circleOptions);
        googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(
                circleOptions.getCenter(), getZoomLevel(circle)));
    } catch (Exception e) {
        AppLogger.logError(TAG, e.getMessage());
    }

}

/**
 * @param circle : circle
 * @return : return zoom level according to circle radius
 */
public float getZoomLevel(Circle circle) {
    int zoomLevel = 11;
    if (circle != null) {
        double radius = circle.getRadius() + circle.getRadius() / 2;
        double scale = radius / 500;
        zoomLevel = (int) (16 - Math.log(scale) / Math.log(2));
    }
    return zoomLevel+.4f;
}

score 0 · Answer 5 · answered Jul 03 '21 at 12:30

  double getZoomLevel() {
    double zoomLevel = 0.0;
    double newRadius = radiusOfCircle + radiusOfCircle / 2;
    double scale = newRadius / 500;
    zoomLevel = (6 - log(scale) / log(2));
    return zoomLevel;
  }

This worked for me

Thanks to @Anand Tiwari

How to find zoom level based on circle draw on map

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