determine current zoomscale for mapview

Question

How can I calculate the current zoomScale for an MKMapView?

Check this question http://stackoverflow.com/questions/1166444/mkmapview-zoom-and-region - may be it will help — Vladimir, May 11 '11 at 15:26
I am actually using TroyBrant's MKMapView category to get the zoomLevel, but I also need zoomScale. — Bryan Clark, May 11 '11 at 15:37

score 0 · Answer 1 · answered Jan 27 '14 at 12:42

Use the following code:

#define MERCATOR_RADIUS 85445659.44705395
#define MAX_GOOGLE_LEVELS 20

- (double)getZoomLevel {
    CLLocationDegrees longitudeDelta = self.mapView.region.span.longitudeDelta;
    CGFloat mapWidthInPixels = self.mapView.bounds.size.width;
    double zoomScale = longitudeDelta * MERCATOR_RADIUS * M_PI / (180.0 * mapWidthInPixels);
    double zoomer = MAX_GOOGLE_LEVELS - log2( zoomScale );
    if ( zoomer < 0 ) zoomer = 0;
    //  zoomer = round(zoomer);
    return zoomer;
}

The return value of the getZoomLevel method will be the current zoom level of your mapView property.

determine current zoomscale for mapview

1 Answers1