纬度、经度及其 delat 值之间有什么区别

发布于 2024-08-30 05:05:03 字数 192 浏览 0 评论 0原文

我是 MKMapView (iPhone) 的新手。我想向哥本哈根（丹麦）地图添加几个注释。我有城市不同位置的纬度和经度值。但我不知道如何获取这些位置的 longitudeDelta 和 latitudeDelta 。我正在使用 Google 地图 API 来计算城市地图中每个位置的纬度和经度值（通过网络服务）。我需要有关如何计算增量值的帮助，

谢谢

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滥情空心 2024-09-06 05:05:03

从你的问题中我不确定你要计算纬度和经度增量的目的是什么，但我在 MKMapView 中看到的唯一参考是在 MKCooperativeSpan 的规范中建立要显示的 MapView 的缩放级别。

我在网上找到了这段代码，它将采用将注释添加到注释层的 MapView，并计算和设置要显示的区域，以使所有注释在 MapView 中可见。也许这会有所帮助

CLLocationCoordinate2D topLeftCoord;
topLeftCoord.latitude = -90;
topLeftCoord.longitude = 180;

CLLocationCoordinate2D bottomRightCoord;
bottomRightCoord.latitude = 90;
bottomRightCoord.longitude = -180;

for(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;
region.span.latitudeDelta = fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.8; // Add a little extra space on the sides
region.span.longitudeDelta = fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.8; // Add a little extra space on the sides

region = [self.mapView regionThatFits:region];
[self.mapView setRegion:region animated:NO];

I'm not certain from your question what purpose you are looking to calculate lat and long deltas, but the only reference I have seen int he MKMapView is in the specification of the MKCoordinateSpan to establish the zoom level of the MapView to display.

I found this code on the Net somewhere that will take a MapView with annotations added to the annotation layer, and calculate and set the region to display to make all annotations visible in the MapView. Perhaps this will help

CLLocationCoordinate2D topLeftCoord;
topLeftCoord.latitude = -90;
topLeftCoord.longitude = 180;

CLLocationCoordinate2D bottomRightCoord;
bottomRightCoord.latitude = 90;
bottomRightCoord.longitude = -180;

for(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;
region.span.latitudeDelta = fabs(topLeftCoord.latitude - bottomRightCoord.latitude) * 1.8; // Add a little extra space on the sides
region.span.longitudeDelta = fabs(bottomRightCoord.longitude - topLeftCoord.longitude) * 1.8; // Add a little extra space on the sides

region = [self.mapView regionThatFits:region];
[self.mapView setRegion:region animated:NO];

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