MKMapRectMake设置后如何缩小

Question

我用MKMapRectMake标记东北和西南来显示一个区域。我是这样做的：

routeRect = MKMapRectMake(southWestPoint.x, southWestPoint.y, northEastPoint.x - southWestPoint.x, northEastPoint.y - southWestPoint.y);
[self.mapView setVisibleMapRect:routeRect];

我设置了这个显示区域后，如何才能把地图缩小一点呢？做这个的最好方式是什么？

更新

这是我用来获取rect函数的代码setVisibleMapRect：

for(Path* p in ar)
    {
        self.routeLine = nil;
        self.routeLineView = nil;

        // while we create the route points, we will also be calculating the bounding box of our route
        // so we can easily zoom in on it.
        MKMapPoint northEastPoint;
        MKMapPoint southWestPoint;

        // create a c array of points.
        MKMapPoint* pointArr = malloc(sizeof(CLLocationCoordinate2D) * ar.count);

        for(int idx = 0; idx < ar.count; idx++)
        {
            Path *m_p = [ar objectAtIndex:idx];
            [NSCharacterSet characterSetWithCharactersInString:@","]];



            CLLocationDegrees latitude  = m_p.Latitude;
            CLLocationDegrees longitude = m_p.Longitude;

            // create our coordinate and add it to the correct spot in the array
            CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake(latitude, longitude);


            MKMapPoint point = MKMapPointForCoordinate(coordinate);

            // adjust the bounding box
            // if it is the first point, just use them, since we have nothing to compare to yet.
            if (idx == 0) {
                northEastPoint = point;
                southWestPoint = point;
            }
            else
            {
                if (point.x > northEastPoint.x)
                    northEastPoint.x = point.x;
                if(point.y > northEastPoint.y)
                    northEastPoint.y = point.y;
                if (point.x < southWestPoint.x)
                    southWestPoint.x = point.x;
                if (point.y < southWestPoint.y)
                    southWestPoint.y = point.y;
            }

            pointArr[idx] = point;
        }

        // create the polyline based on the array of points.
        self.routeLine = [MKPolyline polylineWithPoints:pointArr count:ar.count];

        _routeRect = MKMapRectMake(southWestPoint.x, southWestPoint.y, northEastPoint.x - southWestPoint.x, northEastPoint.y - southWestPoint.y);
        // clear the memory allocated earlier for the points
        free(pointArr);


        [self.mapView removeOverlays: self.mapView.overlays];
        // add the overlay to the map
        if (nil != self.routeLine) {
            [self.mapView addOverlay:self.routeLine];
        }

        // zoom in on the route.
        [self zoomInOnRoute];

    } 

Answer 1

试试这个：（编辑）

    MKCoordinateRegion region;
    MKCoordinateSpan span;
    span.latitudeDelta = 0.01;
    span.longitudeDelta = 0.01;
    CLLocationCoordinate2D zoomLocation = newLocation.coordinate;
    region.center = zoomLocation;
    region.span = span;
    region = [mapViewObject regionThatFits:region];
    [mapViewObject setRegion:region animated:NO];