iOS - Displaying all annotations - ios

I am currently working on a piece of functionality using the MapKit. I have ran into a slight problem. Currently I have all my annotations on my map and are displaying when you move the map around.
However, I am trying to get all my pins to be displayed at the same time. I know this isn't possible due to the below link and the limitations of the zoom - my pins can spread across the entire world.
Now I know this is outside of our control but in this scenario the map can sometimes centre between annotations. For example:
Pin in Antartica
Pin in Artic Ocean above Russia.
It will focus the centre of the map roughly on India - 1/2 point between the two pins.
Is there a way of forcing at least one or more pins to be visible if none are visible?
All Annotation is not visible to user in MKMapView

You can try this to zoom out and show all annotations
func zoomToFitMapAnnotations(aMapView:MKMapView)
{
if(aMapView.annotations.count == 0)
{
return
}
var topLeftCoord = CLLocationCoordinate2D.init(latitude: -90, longitude: 180)
var bottomRightCoord = CLLocationCoordinate2D.init(latitude: 90, longitude: -180)
for i in 0..<myMapView.annotations.count
{
let annotation = myMapView.annotations[i]
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);
}
let resd = CLLocationCoordinate2D.init(latitude: topLeftCoord.latitude - (topLeftCoord.latitude - bottomRightCoord.latitude) * 0.5, longitude: topLeftCoord.longitude + (bottomRightCoord.longitude - topLeftCoord.longitude) * 0.5)
let span = MKCoordinateSpan.init(latitudeDelta: fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.3, longitudeDelta: fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.3)
var region = MKCoordinateRegion.init(center: resd, span: span);
region = aMapView.regionThatFits(region)
aMapView.setRegion(region, animated: true)
}

Related

MKMapView zoom to show all annotations in frame

I have a full screen map, and I want to zoom to a level where all annotations are visible on the map, but only in the content area of the app, as specified by this image:
As you can see, the map fills the entire screen, however, there are rectangles overlayed on the top and bottom which cover the map. The content area is the part that's bright green. Given an array of annotations, I want to be able to zoom the map so that all are visible within that green content area, and not within the actual frame of the map.
I'm using this (category) method here which does the default task of zooming to fit in the frame of the map. But I'm getting stuck on how to modify this to factor in only the content area:
- (void)zoomToShowAnnotations:(NSArray *)annotations extraPaddingMultiplier:(CGFloat)multiplier
{
CLLocationCoordinate2D topLeftCoord;
topLeftCoord.latitude = -90;
topLeftCoord.longitude = 180;
CLLocationCoordinate2D bottomRightCoord;
bottomRightCoord.latitude = 90;
bottomRightCoord.longitude = -180;
for(id<MKAnnotation> annotation in annotations)
{
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);
}
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) * (multiplier != 0 ? multiplier : 1); // Add a little extra space on the sides
region.span.longitudeDelta = fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * (multiplier != 0 ? multiplier : 1); // Add a little extra space on the sides
[self setRegion:region animated:YES];
}
According to documentation this method should to the job.
// Position the map such that the provided array of annotations are all visible to the fullest extent possible.
#available(iOS 7.0, *)
open func showAnnotations(_ annotations: [MKAnnotation], animated: Bool)
You'll have to set an array of your annotations and put it in the function like this
let annotation = MKPointAnnotation()
annotation.coordinate = CLLocationCoordinate2D(latitude: 11.12, longitude: 12.11)
mapView.addAnnotation(annotation)
mapView.showAnnotations([annotation], animated: true)
This is just a list of steps, no actual code or anything.
Compute the aspect ratio of the region you have found.
If the aspect ratio is relatively wider than (or equal to) your desired ratio, go to step 5.
Construct a new region fitting your existing region and whose aspect ratio matches your desired ratio (expand the width).
Construct a new region fitting your expanded region within the screen (expand the height).
Party down.

MKMap zoom to include annotations and region

I am trying to set the zoom level of the map to include just the annotations, but also don't zoom below say a 3 mile radius, but I also don't the annotations touching the side of the screens. Further, I would also like the annotations once zoomed to be within the bottom half self.view (my map takes up the entire screen).
I tried the following two ways and neither works.
// #1 ///// Always zooms to show my annotation in Texas, zoomed out to far I can't even see US states
-(void)zoomToFitMapAnnotations:(MKMapView*)aMapView {
if([aMapView.annotations count] == 0) {
return;
}
CLLocationCoordinate2D topLeftCoord;
topLeftCoord.latitude = -90;
topLeftCoord.longitude = -180;
CLLocationCoordinate2D bottomRightCoord;
bottomRightCoord.latitude = 90;
bottomRightCoord.longitude = -180;
for (id <MKAnnotation> annotation in self.mapView.annotations){
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);
}
MKCoordinateRegion region;
region.center.latitude = topLeftCoord.latitude - (topLeftCoord.latitude - bottomRightCoord.latitude) * 0.5;
region.center.longitude = topLeftCoord.longitude + (bottomRightCoord.longitude - topLeftCoord.longitude) * 0.5;
//Add a little space on both sides
region.span.latitudeDelta = fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.1;
//Add a little extra space on bith sides
region.span.longitudeDelta = fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.1;
region = [aMapView regionThatFits:region];
[self.mapView setRegion:region animated:YES];
}
// #2 ///// This works best, but it zooms in to much; right on top of a house, if there is only one annotation, but I want to see the one annotation and a 4 mile radius. So I never want to zoom less than having 4 square miles shown, UNLESS the user manually zooms it.
MKMapRect zoomRect = MKMapRectNull;
for (id <MKAnnotation> annotation in self.mapView.annotations)
{
MKMapPoint annotationPoint = MKMapPointForCoordinate(annotation.coordinate);
MKMapRect pointRect = MKMapRectMake(annotationPoint.x, annotationPoint.y, 0.1, 0.1);
zoomRect = MKMapRectUnion(zoomRect, pointRect);
}
[self.mapView setVisibleMapRect:zoomRect edgePadding:UIEdgeInsetsMake(300, 300, 100, 300) animated:YES];
MKMapRect zoomRect = MKMapRectNull;
for (id <MKAnnotation> annotation in self.mapView.annotations) {
MKMapPoint annotationPoint = MKMapPointForCoordinate(annotation.coordinate);
MKMapRect pointRect = MKMapRectMake(annotationPoint.x, annotationPoint.y, 0.1, 0.1);
if (MKMapRectIsNull(zoomRect)) {
zoomRect = pointRect;
}else{
zoomRect = MKMapRectUnion(zoomRect, pointRect);
}
}
if (zoomRect.size.width == 0.10) /* for single annotation available in map */
{
zoomRect = MKMapRectMake(zoomRect.origin.x, zoomRect.origin.y, 100000, 100000);
}
[[self mapView] setVisibleMapRect:zoomRect edgePadding:UIEdgeInsetsMake(50, 50, 50, 50) animated:YES];

Zoom MKMapView to best fit distance zoom level based on list of locations

I have a center location I want my MKMapView to zoom to and also a list of locations (latitude/longitude). I would like to set the zoom level (distance) based on this list of locations so that as many of these locations are visible on the MKMapView at the same time, but with a minimum zoom level (or max distance) so that my MKMapView does not zoom out to much.
So lets say I have a list of 10 locations but one of those locations is so far away from my center location that if I show that one location on the MKMapView it will be zoomed out to much, how do I calculate the distance parameters for MKCoordinateRegionMakeWithDistance?
I hope I explained my problem well enough, I have difficulties explaining it I think.
Thank you
Søren
I got it working with the following solution.
I use the Great-circle distance formula to calculate the distance between my center point and all the found lat/long points, and if this distance is greater than my minimum distance and my maximum distance and larger than my "last found distance" I set this distance to be my zoom distance. It works like a charm and was actually quite simple.
Here is my distance calculation code:
-(double)distanceBetweenLocations:(CLLocationCoordinate2D)c1 :(CLLocationCoordinate2D)c2 {
int r = 6371 * 1000;//meters
double dLat = (c2.latitude - c1.latitude) * M_PI / 180;
double dLon = (c2.longitude - c1.longitude) * M_PI / 180;
double lat1 = c1.latitude * M_PI / 180;
double lat2 = c2.latitude * M_PI / 180;
double a = sin(dLat / 2) * sin(dLat / 2) + sin(dLon / 2) * sin(dLon / 2) * cos(lat1) * cos(lat2);
double c = 2 * atan2(sqrt(a), sqrt(1 - a));
double d = r * c;
return d;
}
And here is my code that zooms to my center point with the calculated distance:
-(void)zoomToLocation {
double MAX_DISTANCE = 10000.0;
double MIN_DISTANCE = 600.0;
double zoomDistance = MIN_DISTANCE;
CLLocationCoordinate2D center;
center.latitude = self.searchLocationLatitude;
center.longitude = self.searchLocationLongitude;
BOOL treaterVisible = NO;
for (Treater *treater in treaters) {
CLLocationCoordinate2D c2;
c2.latitude = treater.latitude;
c2.longitude = treater.longitude;
double distance = [self distanceBetweenLocations:center :c2];
if(distance > zoomDistance && distance < MAX_DISTANCE) {
zoomDistance = distance;
treaterVisible = YES;
}
}
if(!treaterVisible) {
zoomDistance = MAX_DISTANCE;
}
CLLocationCoordinate2D location;
location.latitude = self.searchLocationLatitude;
location.longitude = self.searchLocationLongitude;
MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(location, zoomDistance, zoomDistance);
MKCoordinateRegion adjustedRegion = [self.mapView regionThatFits:region];
[self.mapView setRegion:adjustedRegion];
}
Just if anybody should need something similar.
Best regards
Søren
Edit didAddAnnotationViews method. I hope this is what you are looking for,
-(void) mapView:(MKMapView *)mapView didAddAnnotationViews:(NSArray *)views
{
MKMapRect zoomRect = MKMapRectNull;
for (id <MKAnnotation> annotation in mapView.annotations)
{
MKMapPoint annotationPoint = MKMapPointForCoordinate(annotation.coordinate);
MKMapRect pointRect = MKMapRectMake(annotationPoint.x, annotationPoint.y, 0.1, 0.1);
if (MKMapRectIsNull(zoomRect)) {
zoomRect = pointRect;
} else {
zoomRect = MKMapRectUnion(zoomRect, pointRect);
}
}
[mapView setVisibleMapRect:zoomRect animated:YES];
}
DDAnnotation is custom class for display pin(PlaceMark)
-(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(DDAnnotation* annotation in mapView.annotations)
{
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];
}
Some days ago i have read a solution to your problem in a book, I think it is Preparata Shamos, Computational Geometry.
Unfortunatley the solution is komplex: it is the question: find the best/max subset of points that are visible withing a given radius.
if your point count is not to high, less than ten thousands, i would do it as follows
0) add all point to current selected subset.
1) iterate through all points insubset, calcualte gravity point, calc all distances to gravity point, does it fit the max zoom level desired distance? yes the ready.
2) No? the remove the point from subset, with highest distance, and do step 1 again.
Do that till all points are within the desired distance from the current subset center.
The gravity point is that point in the subset with average x (or longitude) and average y ( or latitude) coordinate.
(If you accept, please dont upvote)
For this we need to find the minimum and maximum latitude and longitude, after that we need make the region with average sum of these latitude and longitude. then assign the region to the mapview and fit the region on it. thats it.

What's the best way to zoom out and fit all annotations in MapKit

Quick background of what I have going on. UIMapView loads and shows a single annotation (Never more than one). On the menu bar, there is a Locate Me button, on tap the userLocation is found and displayed as a second annotation. I then I have MapView zoom out to fit both those annotations in range but I am unable to find a suitable way of doing so. Depending on where the first annotation is placed in relation to the user location, sometimes it doesn't zoom out enough.
For example, if the annotation is North West of the User, it zooms out fine. But if the annotation is South East of the User, it only zooms out enough that they are just getting cut off and you have to manually zoom out a bit more. Here's the code I am using, variation of some others I have found on SO.
CLLocation *whereIAm = mapView.userLocation.location;
float lat = whereIAm.coordinate.latitude;
float lon = whereIAm.coordinate.longitude;
CLLocationCoordinate2D southWest = {[currentLatitude floatValue], [currentLongitude floatValue]};
CLLocationCoordinate2D northEast = southWest;
southWest.latitude = MIN(southWest.latitude, lat);
southWest.longitude = MIN(southWest.longitude, lon);
northEast.latitude = MAX(northEast.latitude, lat);
northEast.longitude = MAX(northEast.longitude, lon);
CLLocation *locSouthWest = [[CLLocation alloc] initWithLatitude:southWest.latitude longitude:southWest.longitude];
CLLocation *locNorthEast = [[CLLocation alloc] initWithLatitude:northEast.latitude longitude:northEast.longitude];
CLLocationDistance meters = [locSouthWest distanceFromLocation:locNorthEast];
MKCoordinateRegion region;
region.center.latitude = (southWest.latitude + northEast.latitude) / 2.0;
region.center.longitude = (southWest.longitude + northEast.longitude) / 2.0;
region.span.latitudeDelta = meters / 111319.5
region.span.longitudeDelta = 7.0;
MKCoordinateRegion savedRegion = [mapView regionThatFits:region];
[mapView setRegion:savedRegion animated:YES];
[locSouthWest release];
[locNorthEast release];
Is there a better way built into MapKit to just zoom out so that both annotations have, lets say half an inch between them at the outer frame? I don't really care if the user has to zoom in after, I just want it to zoom out properly.
-(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(MapAnnotation* annotation in mapView.annotations)
{
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);
}
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; // Add a little extra space on the sides
region.span.longitudeDelta = fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.1; // Add a little extra space on the sides
region = [mapView regionThatFits:region];
[mapView setRegion:region animated:YES];
}
Taken from: http://codisllc.com/blog/zoom-mkmapview-to-fit-annotations/
(Use it all the time.)
In iOS7 there's a method that does just that. Just call:
[yourMapView showAnnotations:yourAnnotationsArray animated:YES];
Those who do the monotouch c# coding
BasicMapAnnotation is inherit class from MKAnnotation
private void GetRegion(MKMapView mapView)
{
var userWasVisible = mapView.ShowsUserLocation;
mapView.ShowsUserLocation = false; // ignoring the blue blip
// start with the widest possible viewport
var tl = new CLLocationCoordinate2D(-90, 180); // top left
var br = new CLLocationCoordinate2D(90, -180); // bottom right
foreach (var an in mapView.Annotations)
{
// narrow the viewport bit-by-bit
CLLocationCoordinate2D coordinate = ((BasicMapAnnotation) an).Coordinate;
tl.Longitude = Math.Min(tl.Longitude, coordinate.Longitude);
tl.Latitude = Math.Max(tl.Latitude, coordinate.Latitude);
br.Longitude = Math.Max(br.Longitude, coordinate.Longitude);
br.Latitude = Math.Min(br.Latitude, coordinate.Latitude);
}
var center = new CLLocationCoordinate2D
{
// divide the range by two to get the center
Latitude = tl.Latitude - (tl.Latitude - br.Latitude)*0.5,Longitude = tl.Longitude + (br.Longitude - tl.Longitude)*0.5
};
var span = new MKCoordinateSpan
{
// calculate the span, with 20% margin so pins aren’t on the edge
LatitudeDelta = Math.Abs(tl.Latitude - br.Latitude)*1.2,LongitudeDelta = Math.Abs(br.Longitude - tl.Longitude)*1.2
};
var region = new MKCoordinateRegion {Center = center, Span = span};
region = mapView.RegionThatFits(region); // adjusts zoom level too
mapView.SetRegion(region, true); // animated transition
mapView.ShowsUserLocation =
userWasVisible;
}
You can use this code to show all annotations
MKMapRect zoomRect = MKMapRectNull;
for (id <MKAnnotation> annotation in mapView.annotations)
{
MKMapPoint annotationPoint = MKMapPointForCoordinate(annotation.coordinate);
MKMapRect pointRect = MKMapRectMake(annotationPoint.x, annotationPoint.y, 0.1, 0.1);
zoomRect = MKMapRectUnion(zoomRect, pointRect);
}
[mapView setVisibleMapRect:zoomRect animated:YES];
if you want to include user location just replace two lines below with the first line of above code
MKMapPoint annotationPoint = MKMapPointForCoordinate(mapView.userLocation.coordinate);
MKMapRect zoomRect = MKMapRectMake(annotationPoint.x, annotationPoint.y, 0.1, 0.1);

iPhone Map Region Weirdness

The attached image is what happens sometimes when I try to size a MKMapView to fit one or more placemarks. It's intermittent, but the display is always in exactly the same position.
Here is the code:
// loc1 is always non-null, and is equal to one of the annotation locations
CLLocationCoordinate2D topLeftCoord = loc1.coordinate;
CLLocationCoordinate2D bottomRightCoord = loc1.coordinate;
for(UserPlacemark* annotation in self.mapView.annotations)
{
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);
}
MKCoordinateRegion region;
double k = 0.01;
region.center.latitude = topLeftCoord.latitude - (topLeftCoord.latitude - bottomRightCoord.latitude) * 0.25;
region.center.longitude = topLeftCoord.longitude + (bottomRightCoord.longitude - topLeftCoord.longitude) * 0.5;
region.span.latitudeDelta = k + fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.25; // Add a little extra space on the sides
region.span.longitudeDelta = k + fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.5; // Add a little extra space on the sides
// only zoom if region doesn't fit, or too small
CGRect newRect = [mapView convertRegion:region toRectToView:mapView];
double MIN_SIZE_PIXELS = 50.0;
double rectSizePixels = newRect.size.width+newRect.size.height;
if (!CGRectContainsRect(mapView.bounds, newRect) || rectSizePixels < MIN_SIZE_PIXELS)
{
region = [mapView regionThatFits:region];
[mapView setRegion:region animated:TRUE];
}
The problem in the above code is that a MKUserAnnotation instance is placed in the placemark list by the Map framework. This does not always correspond with the user's actual position, at least in the simulator.
It's better to avoid iterating over the annotations list and instead compute the min/max boundaries of your placemark using your objects directly.

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