答案 0 :(得分：13)
您可以使用REVClusterMap群集
答案 1 :(得分：8)
注意：这是我附属的商业产品，但它解决了这个问题。
我在一些应用程序中解决了这个问题，并决定将其解压缩到可重用的框架中。它被称为Superpin，它是一个（商业，许可证成本为149美元）iOS框架，内部使用四叉树进行注释存储并执行基于网格的群集。该算法非常快，包含的示例应用程序显示了世界上的机场（超过30k +注释），并且它在3G iPhone上运行得相当顺畅。
答案 2 :(得分：6)
这可能有点像使用电锯割草坪，但这里摘录自Algorithms in a Nutshell
创建KD树......
public class KDFactory {
// Known comparators for partitioning points along dimensional axes.
private static Comparator<IMultiPoint> comparators[ ] ;
// Recursively construct KDTree using median method on input points.
public static KDTree generate (IMultiPoint [ ] points) {
if (points. length == 0) { return null; }
// median will be the root.
int maxD = points[ 0] . dimensionality( );
KDTree tree = new KDTree(maxD) ;
// Make dimensional comparators that compare points by ith dimension
comparators = new Comparator[ maxD+1] ;
for (int i = 1; i <= maxD; i++) {
comparators[ i] = new DimensionalComparator(i) ;
}
tree. setRoot(generate (1, maxD, points, 0, points. length-1) ) ;
return tree;
}
// generate the node for the d-th dimension (1 <= d <= maxD)
// for points[ left, right]
private static DimensionalNode generate (int d, int maxD,
IMultiPoint points[ ] ,
int left, int right) {
// Handle the easy cases first
if (right < left) { return null; }
if (right == left) { return new DimensionalNode (d, points[ left] ) ; }
// Order the array[ left, right] so the mth element will be the median
// and the elements prior to it will all be <=, though they won' t
// necessarily be sorted; similarly, the elements after will all be >=
int m = 1+(right-left) /2;
Selection. select(points, m, left, right, comparators[ d] ) ;
// Median point on this dimension becomes the parent
DimensionalNode dm = new DimensionalNode (d, points[ left+m-1] ) ;
// update to the next dimension, or reset back to 1
if (++d > maxD) { d = 1; }
// recursively compute left and right sub-trees, which translate
// into ' below' and ' above' for n-dimensions.
dm. setBelow(maxD, generate (d, maxD, points, left, left+m-2) ) ;
dm. setAbove(maxD, generate (d, maxD, points, left+m, right) ) ;
return dm;
}
}
最佳找到最近邻居：O（log n）最差O（n）
// method in KDTree
public IMultiPoint nearest (IMultiPoint target) {
if (root == null) return null;
// find parent node to which target would have been inserted. This is our
// best shot at locating closest point; compute best distance guess so far
DimensionalNode parent = parent(target) ;
IMultiPoint result = parent. point;
double smallest = target. distance(result) ;
// now start back at the root, and check all rectangles that potentially
// overlap this smallest distance. If better one is found, return it.
double best[ ] = new double[ ] { smallest };
double raw[ ] = target. raw( );
IMultiPoint betterOne = root. nearest (raw, best) ;
if (betterOne ! = null) { return betterOne; }
return result;
}
// method in DimensionalNode. min[ 0] contains best computed shortest distance.
IMultiPoint nearest (double[ ] rawTarget, double min[ ] ) {
// Update minimum if we are closer.
IMultiPoint result = null;
// If shorter, update minimum
double d = shorter(rawTarget, min[ 0] ) ;
if (d >= 0 && d < min[ 0] ) {
min[ 0] = d;
result = point;
}
// determine if we must dive into the subtrees by computing direct
// perpendicular distance to the axis along which node separates
// the plane. If d is smaller than the current smallest distance,
// we could "bleed" over the plane so we must check both.
double dp = Math. abs(coord - rawTarget[ dimension-1] ) ;
IMultiPoint newResult = null;
if (dp < min[ 0] ) {
// must dive into both. Return closest one.
if (above ! = null) {
newResult = above. nearest (rawTarget, min) ;
if (newResult ! = null) { result = newResult; }
}
if (below ! = null) {
newResult = below. nearest(rawTarget, min) ;
if (newResult ! = null) { result = newResult; }
}
} else {
// only need to go in one! Determine which one now.
if (rawTarget[ dimension-1] < coord) {
if (below ! = null) {
newResult = below. nearest (rawTarget, min) ;
}
} else {
if (above ! = null) {
newResult = above. nearest (rawTarget, min) ;
}
}
// Use smaller result, if found.
if (newResult ! = null) { return newResult; }
}
return result;
}
答案 3 :(得分：6)
我尝试了其他建议，我也发现OCMapView效果最佳。
它是免费的，允许轻松分组注释，这是我需要的。它更新一点＆amp;比Revolver更新，对我来说更容易实现。
答案 4 :(得分：1)
概念验证是离线地图应用“OffMaps”;）
答案 5 :(得分：1)
我最近不得不使用MapKit实现注释聚类。根据您的使用情况，上述解决方案很好。我最终选择了FBAnnotationClustering（Objective-C）因为它是免费的，并且在github上有很多明星和几个问题：
https://github.com/infinum/FBAnnotationClustering
我正在处理的应用程序非常以地图为中心，因此将FBAnnotationClustering转换为Swift是有意义的。这是关于该方法的博客文章，其中包含github上示例项目的链接。
答案 6 :(得分：0)
受WWDC 2011视频的启发，此代码对我来说非常有用。也许不是这里提出的最快的，但它是免费的，它绝对是最简单的。
它基本上使用2张地图。一个是隐藏的并保存每个注释（我的代码中的allAnnotationMapView）。一个是可见的，只显示集群或注释，如果是单个（我的代码中的mapView）。
- (void)didZoom:(UIGestureRecognizer*)gestureRecognizer {
if (gestureRecognizer.state == UIGestureRecognizerStateEnded){
[self updateVisibleAnnotations];
}
}
- (void)updateVisibleAnnotations {
static float marginFactor = 2.0f;
static float bucketSize = 50.0f;
MKMapRect visibleMapRect = [self.mapView visibleMapRect];
MKMapRect adjustedVisibleMapRect = MKMapRectInset(visibleMapRect, -marginFactor * visibleMapRect.size.width, -marginFactor * visibleMapRect.size.height);
CLLocationCoordinate2D leftCoordinate = [self.mapView convertPoint:CGPointZero toCoordinateFromView:self.view];
CLLocationCoordinate2D rightCoordinate = [self.mapView convertPoint:CGPointMake(bucketSize, 0) toCoordinateFromView:self.view];
double gridSize = MKMapPointForCoordinate(rightCoordinate).x - MKMapPointForCoordinate(leftCoordinate).x;
MKMapRect gridMapRect = MKMapRectMake(0, 0, gridSize, gridSize);
double startX = floor(MKMapRectGetMinX(adjustedVisibleMapRect) / gridSize) * gridSize;
double startY = floor(MKMapRectGetMinY(adjustedVisibleMapRect) / gridSize) * gridSize;
double endX = floor(MKMapRectGetMaxX(adjustedVisibleMapRect) / gridSize) * gridSize;
double endY = floor(MKMapRectGetMaxY(adjustedVisibleMapRect) / gridSize) * gridSize;
gridMapRect.origin.y = startY;
while(MKMapRectGetMinY(gridMapRect) <= endY) {
gridMapRect.origin.x = startX;
while (MKMapRectGetMinX(gridMapRect) <= endX) {
NSSet *allAnnotationsInBucket = [self.allAnnotationMapView annotationsInMapRect:gridMapRect];
NSSet *visibleAnnotationsInBucket = [self.mapView annotationsInMapRect:gridMapRect];
NSMutableSet *filteredAnnotationsInBucket = [[allAnnotationsInBucket objectsPassingTest:^BOOL(id obj, BOOL *stop) {
BOOL isPointMapItem = [obj isKindOfClass:[PointMapItem class]];
BOOL shouldBeMerged = NO;
if (isPointMapItem) {
PointMapItem *pointItem = (PointMapItem *)obj;
shouldBeMerged = pointItem.shouldBeMerged;
}
return shouldBeMerged;
}] mutableCopy];
NSSet *notMergedAnnotationsInBucket = [allAnnotationsInBucket objectsPassingTest:^BOOL(id obj, BOOL *stop) {
BOOL isPointMapItem = [obj isKindOfClass:[PointMapItem class]];
BOOL shouldBeMerged = NO;
if (isPointMapItem) {
PointMapItem *pointItem = (PointMapItem *)obj;
shouldBeMerged = pointItem.shouldBeMerged;
}
return isPointMapItem && !shouldBeMerged;
}];
for (PointMapItem *item in notMergedAnnotationsInBucket) {
[self.mapView addAnnotation:item];
}
if(filteredAnnotationsInBucket.count > 0) {
PointMapItem *annotationForGrid = (PointMapItem *)[self annotationInGrid:gridMapRect usingAnnotations:filteredAnnotationsInBucket];
[filteredAnnotationsInBucket removeObject:annotationForGrid];
annotationForGrid.containedAnnotations = [filteredAnnotationsInBucket allObjects];
[self.mapView addAnnotation:annotationForGrid];
//force reload of the image because it's not done if annotationForGrid is already present in the bucket!!
MKAnnotationView* annotationView = [self.mapView viewForAnnotation:annotationForGrid];
NSString *imageName = [AnnotationsViewUtils imageNameForItem:annotationForGrid selected:NO];
UILabel *countLabel = [[UILabel alloc] initWithFrame:CGRectMake(15, 2, 8, 8)];
[countLabel setFont:[UIFont fontWithName:POINT_FONT_NAME size:10]];
[countLabel setTextColor:[UIColor whiteColor]];
[annotationView addSubview:countLabel];
imageName = [AnnotationsViewUtils imageNameForItem:annotationForGrid selected:NO];
annotationView.image = [UIImage imageNamed:imageName];
if (filteredAnnotationsInBucket.count > 0){
[self.mapView deselectAnnotation:annotationForGrid animated:NO];
}
for (PointMapItem *annotation in filteredAnnotationsInBucket) {
[self.mapView deselectAnnotation:annotation animated:NO];
annotation.clusterAnnotation = annotationForGrid;
annotation.containedAnnotations = nil;
if ([visibleAnnotationsInBucket containsObject:annotation]) {
CLLocationCoordinate2D actualCoordinate = annotation.coordinate;
[UIView animateWithDuration:0.3 animations:^{
annotation.coordinate = annotation.clusterAnnotation.coordinate;
} completion:^(BOOL finished) {
annotation.coordinate = actualCoordinate;
[self.mapView removeAnnotation:annotation];
}];
}
}
}
gridMapRect.origin.x += gridSize;
}
gridMapRect.origin.y += gridSize;
}
}
- (id<MKAnnotation>)annotationInGrid:(MKMapRect)gridMapRect usingAnnotations:(NSSet *)annotations {
NSSet *visibleAnnotationsInBucket = [self.mapView annotationsInMapRect:gridMapRect];
NSSet *annotationsForGridSet = [annotations objectsPassingTest:^BOOL(id obj, BOOL *stop) {
BOOL returnValue = ([visibleAnnotationsInBucket containsObject:obj]);
if (returnValue) {
*stop = YES;
}
return returnValue;
}];
if (annotationsForGridSet.count != 0) {
return [annotationsForGridSet anyObject];
}
MKMapPoint centerMapPoint = MKMapPointMake(MKMapRectGetMinX(gridMapRect), MKMapRectGetMidY(gridMapRect));
NSArray *sortedAnnotations = [[annotations allObjects] sortedArrayUsingComparator:^(id obj1, id obj2) {
MKMapPoint mapPoint1 = MKMapPointForCoordinate(((id<MKAnnotation>)obj1).coordinate);
MKMapPoint mapPoint2 = MKMapPointForCoordinate(((id<MKAnnotation>)obj2).coordinate);
CLLocationDistance distance1 = MKMetersBetweenMapPoints(mapPoint1, centerMapPoint);
CLLocationDistance distance2 = MKMetersBetweenMapPoints(mapPoint2, centerMapPoint);
if (distance1 < distance2) {
return NSOrderedAscending;
}
else if (distance1 > distance2) {
return NSOrderedDescending;
}
return NSOrderedSame;
}];
return [sortedAnnotations objectAtIndex:0];
}
答案 7 :(得分：-1)
我认为Foto Brisko（iTunes链接）就是这样做的 我不认为它有一个Cocoa Touch框架。