Question

I have an array of latitude and longitude points. I use them to make markers on the map. What can I do to show all of the markers on the map at the same time. eg make a good fit so that if the markers are within a city I zoom it in to only show the city and not the whole state, country etc…

Thanks

Answer 1

something like this might help

private void centerGroup(int groupId){
    if(groupId>0){
        int minLat = Integer.MAX_VALUE;
        int maxLat = Integer.MIN_VALUE;
        int minLon = Integer.MAX_VALUE;
        int maxLon = Integer.MIN_VALUE;


        Cursor cursor = getYourLantLongs(groupId);

        if (cursor.moveToFirst()){
            final int LAT_INDEX = cursor.getColumnIndex(T.Waypoints.LATITUDE);
            final int LON_INDEX = cursor.getColumnIndex(T.Waypoints.LONGITUDE);

            do {
                final int lat = (int) (cursor.getFloat(LAT_INDEX)*1E6);
                final int lon = (int) (cursor.getFloat(LON_INDEX)*1E6);

                maxLat = Math.max(lat, maxLat);
                minLat = Math.min(lat, minLat);
                maxLon = Math.max(lon, maxLon);
                minLon = Math.min(lon, minLon);

            } while(cursor.moveToNext());


            mapController.zoomToSpan(Math.abs(maxLat - minLat), Math.abs(maxLon - minLon));
            mapController.animateTo(new GeoPoint((maxLat + minLat)/2, (maxLon + minLon)/2 ));

            /*
            final int cLat =  (int)((maxLat*1E6 + minLat*1E6)/2);
            final int cLon =  (int)((maxLon*1E6 + minLon*1E6)/2);

            final int zLat =  (int)Math.abs(maxLat - minLat);
            final int zLon =  (int)Math.abs(maxLon - minLon);

            //mapController.zoomToSpan(zLat, zLon);
            mapController.animateTo(new GeoPoint(cLat, cLon));
             */
        }
    }           
}

in short you make a square and zoom in.