Setting region in MKMapView - iphone

Question

I have 10 - 15 lat long to show in map at a time. How should I set region so that I can see all the annotations on the map.

Answer 1

create class as below. create two class: ViewController is class of UIViewController and MapViewAnnotation is class of NSObject. I have created that two class as below. bind mapview in XIB of ViewController and set delegate.
#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#import "MapViewAnnotation.h"
#interface ViewController : UIViewController<MKMapViewDelegate>{
IBOutlet MKMapView* mapView;
NSMutableArray *arrayLocation;
}
#end
#import "ViewController.h"
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
arrayLocation = [[NSMutableArray alloc]init];
NSMutableArray *arrAnnotations = [[NSMutableArray alloc]init];
NSMutableDictionary *dict = [[NSMutableDictionary alloc]init];
[dict setValue:#"32.774125" forKey:#"latitude"];
[dict setValue:#"-117.240658" forKey:#"longitude"];
[dict setValue:#"Bars & Restaurants 1" forKey:#"title"];
[arrayLocation addObject:dict];
dict = nil;
dict = [[NSMutableDictionary alloc]init];
[dict setValue:#"32.784526" forKey:#"latitude"];
[dict setValue:#"-117.240985" forKey:#"longitude"];
[dict setValue:#"Bars & Restaurants 2" forKey:#"title"];
[arrayLocation addObject:dict];
dict = nil;
dict = [[NSMutableDictionary alloc]init];
[dict setValue:#"32.773477" forKey:#"latitude"];
[dict setValue:#"-117.241144" forKey:#"longitude"];
[dict setValue:#"Bars & Restaurants 3" forKey:#"title"];
[arrayLocation addObject:dict];
dict = nil;
dict = [[NSMutableDictionary alloc]init];
[dict setValue:#"32.775301" forKey:#"latitude"];
[dict setValue:#"-117.238893" forKey:#"longitude"];
[dict setValue:#"Bars & Restaurants 4" forKey:#"title"];
[arrayLocation addObject:dict];
dict = nil;
for(int i=0;i<[arrayLocation count];i++)
{
CLLocationCoordinate2D location;
location.latitude = [[[arrayLocation objectAtIndex:i] objectForKey:#"latitude"] doubleValue];
location.longitude = [[[arrayLocation objectAtIndex:i] objectForKey:#"longitude"] doubleValue];
MapViewAnnotation *newAnnotation = [[MapViewAnnotation alloc] initWithTitle:[[arrayLocation objectAtIndex:i] objectForKey:#"title"] Coordinate:location andIndex:i];
[arrAnnotations addObject:newAnnotation];
}
[mapView addAnnotations:arrAnnotations];
mapView.region = [MapViewAnnotation regionForAnnotations:arrAnnotations];
}
- (MKAnnotationView *)mapView:(MKMapView *)map viewForAnnotation:(id <MKAnnotation>)annotation
{
if (annotation == mapView.userLocation)
{
return nil;
}
MKPinAnnotationView *pin = (MKPinAnnotationView *) [mapView dequeueReusableAnnotationViewWithIdentifier: #"restMap"];
if (pin == nil)
{
pin = [[MKPinAnnotationView alloc] initWithAnnotation: annotation reuseIdentifier: #"restMap"];
}
else
{
pin.annotation = annotation;
}
pin.pinColor = MKPinAnnotationColorRed;
pin.animatesDrop = NO;
pin.canShowCallout=TRUE;
UIButton *btn=[UIButton buttonWithType:UIButtonTypeDetailDisclosure];
MapViewAnnotation *temp = (MapViewAnnotation *)pin.annotation;
btn.tag=temp.index;
pin.rightCalloutAccessoryView=btn;
[btn addTarget:self action:#selector(openDetail:) forControlEvents:UIControlEventTouchUpInside];
return pin;
}
#end
Implementation of MapViewAnnotation class
#import <MapKit/MapKit.h>
#interface MapViewAnnotation : NSObject <MKAnnotation , MKMapViewDelegate>{
NSString *title;
int index;
CLLocationCoordinate2D coordinate;
}
#property (nonatomic, copy) NSString *title;
#property (nonatomic, readwrite) int index;
#property (nonatomic, readonly) CLLocationCoordinate2D coordinate;
- (id)initWithTitle:(NSString *)ttl andCoordinate:(CLLocationCoordinate2D)c2d;
- (id)initWithTitle:(NSString *)ttl Coordinate:(CLLocationCoordinate2D)c2d andIndex:(int)intIndex;
+(MKCoordinateRegion) regionForAnnotations:(NSArray*) annotations ;
#end
#import "MapViewAnnotation.h"
#implementation MapViewAnnotation
#synthesize title, coordinate,index;
- (id)initWithTitle:(NSString *)ttl andCoordinate:(CLLocationCoordinate2D)c2d {
self = [super init];
title = ttl;
coordinate = c2d;
return self;
}
- (id)initWithTitle:(NSString *)ttl Coordinate:(CLLocationCoordinate2D)c2d andIndex:(int)intIndex
{
self = [super init];
title = ttl;
coordinate = c2d;
index = intIndex;
return self;
}
+(MKCoordinateRegion) regionForAnnotations:(NSArray*) annotations
{
NSAssert(annotations!=nil, #"annotations was nil");
NSAssert([annotations count]!=0, #"annotations was empty");
double minLat=360.0f, maxLat=-360.0f;
double minLon=360.0f, maxLon=-360.0f;
for (id<MKAnnotation> vu in annotations) {
if ( vu.coordinate.latitude < minLat ) minLat = vu.coordinate.latitude;
if ( vu.coordinate.latitude > maxLat ) maxLat = vu.coordinate.latitude;
if ( vu.coordinate.longitude < minLon ) minLon = vu.coordinate.longitude;
if ( vu.coordinate.longitude > maxLon ) maxLon = vu.coordinate.longitude;
}
CLLocationCoordinate2D center = CLLocationCoordinate2DMake((minLat+maxLat)/2.0, (minLon+maxLon)/2.0);
MKCoordinateSpan span = MKCoordinateSpanMake(maxLat-minLat, maxLon-minLon);
MKCoordinateRegion region = MKCoordinateRegionMake (center, span);
return region;
}
#end

Answer 2

If anyone is looking for a Swift 3 solution, I've written this quick extension that works very well for me :)
public extension MKMapView {
public static func visibleRect(for coords: [CLLocationCoordinate2D]) -> MKMapRect {
return coords.reduce(MKMapRectNull) { outRect, coord in
let point = MKMapPointForCoordinate(coord)
let rect = MKMapRectMake(point.x, point.y, 0.1, 0.1)
let union = MKMapRectUnion(rect, outRect)
return union
}
}
public func fitCoordinates(_ coords: [CLLocationCoordinate2D],
animated: Bool = true,
insets: UIEdgeInsets = UIEdgeInsets(top: 25, left: 25, bottom: 25, right: 25)) {
let rect = MKMapView.visibleRect(for: coords)
self.setVisibleMapRect(rect, edgePadding: insets, animated: animated)
}
}
Which allows to quickly do:
map.fitCoordinates([userLocation, location1, location2])
Hope this helps anyone!
Gist here: https://gist.github.com/freak4pc/1748322a1b8bba23b6de3f47cb00c3ea

Answer 3

try like this may be it helps you,
MKCoordinateSpan span = MKCoordinateSpanMake(52.0f,80.0001f);
CLLocationCoordinate2D coordinate = {8.9999, 18.2812};
MKCoordinateRegion region = {coordinate, span};
MKCoordinateRegion regionThatFits = [self.mapView regionThatFits:region];
NSLog(#"Fit Region %f %f", regionThatFits.center.latitude, regionThatFits.center.longitude);
[self.mapView setRegion:regionThatFits animated:YES];
replace your coordinates and all the values respectively.

Answer 4

For Show All Annotation use this method, i Used this Method in same issue as your. it worked for me.
-(void)zoomToFitMapAnnotations:(MKMapView*)mapView
{
if([mapView.annotations count] == 0)
return;
CLLocationCoordinate2D topLeftCoord;
topLeftCoord.latitude = -90;
topLeftCoord.longitude = 180;
CLLocationCoordinate2D bottomRightCoord;
bottomRightCoord.latitude = 90;
bottomRightCoord.longitude = -180;
for(MYAnnotation* annotation in mapView.annotations)// here MYAnnotation is custom annotation call.
{
topLeftCoord.longitude = fmin(topLeftCoord.longitude, annotation.coordinate.longitude);
topLeftCoord.latitude = fmax(topLeftCoord.latitude, annotation.coordinate.latitude);
bottomRightCoord.longitude = fmax(bottomRightCoord.longitude, annotation.coordinate.longitude);
bottomRightCoord.latitude = fmin(bottomRightCoord.latitude, annotation.coordinate.latitude);
}
NSLog(#"A%f, B%f, C%f, D%f,", topLeftCoord.latitude, topLeftCoord.longitude, bottomRightCoord.latitude, bottomRightCoord.longitude);
MKCoordinateRegion region;
region.center.latitude = topLeftCoord.latitude - (topLeftCoord.latitude - bottomRightCoord.latitude) * 0.5;
region.center.longitude = topLeftCoord.longitude + (bottomRightCoord.longitude - topLeftCoord.longitude) * 0.5;
region.span.latitudeDelta = fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.1;
region.span.longitudeDelta = fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.1;
region = [mapView regionThatFits:region];
[mapView setRegion:region animated:YES];
}
call this method after set all Place(Annotation) on Map View, such like..
[self zoomToFitMapAnnotations:self.mapView];