MKMapView：如何根据Accuracy设置区域跨度？

发布于 2024-08-21 09:05:29 字数 786 浏览 4 评论 0原文

我正在 iPhone 上实现一个地图应用程序。我希望地图放大用户当前的位置。我想根据准确性进行放大（模拟地图应用程序的工作方式）。

我正在实现这个方法：

    - (void)locationManager:(CLLocationManager *)manager 
didUpdateToLocation:(CLLocation *)newLocation 
fromLocation:(CLLocation *)oldLocation {

我面临的问题是 CLLocation 为我提供了 HorizontalAccuracy 和 VerticalAccuracy 属性的精度，最终意味着米。但是，为了使地图居中，我使用以下方法：

MKCoordinateRegion region;
MKCoordinateSpan span;
region.center = newLocation.coordinate; 
span.latitudeDelta=.005;  //THIS IS HARDCODED
span.longitudeDelta=.005; //THIS IS HARDCODED   
region.span = span;

[mapView setRegion:region animated:YES];

我正在寻找一种基于水平精度（以米表示）计算 latitudeDelta （以度表示）的方法。

它不需要是精确的转换（我不期待转换公式，这将需要相当多的计算，包括当前位置），只需一些近似值。

有什么想法吗？

谢谢。贡索

原文

Im implementing a map application on iPhone. I want the map to zoom in on the user's current location.
I'd like to zoom closer based on the accuracy (emulating how the Maps app works).

Im implementing this method:

    - (void)locationManager:(CLLocationManager *)manager 
didUpdateToLocation:(CLLocation *)newLocation 
fromLocation:(CLLocation *)oldLocation {

The problem I face is that CLLocation provides me the accuracy with the properties horizontalAccuracy and verticalAccuracy, that in the end means meters. However, to center the map I using this:

MKCoordinateRegion region;
MKCoordinateSpan span;
region.center = newLocation.coordinate; 
span.latitudeDelta=.005;  //THIS IS HARDCODED
span.longitudeDelta=.005; //THIS IS HARDCODED   
region.span = span;

[mapView setRegion:region animated:YES];

Im looking for a way to calculate the latitudeDelta (represented in degrees) based on the horizontalAccuracy (represented in meters).

It doesn't need to be a exact conversion (Im not looking forward a conversion formula, that will require quite some calculation, including the current location), just some aprox values.

Any ideas?

Thanks.
Gonso

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[旋木] 2024-08-28 09:05:29

无需进行计算。只需使用 MKCooperativeRegionMakeWithDistance() 即可。

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通知家属抬走 2024-08-28 09:05:29

我使用以下代码设置要在 MapView 中显示的中心和跨度。它应该有效。

MKCoordinateRegion region = {{0,0},{.5,.5}}; 
region.center.latitude = doubleLattitude; //user defined
region.center.longitude = doubleLongitude;//user defined
[mapView setRegion:region animated:YES];

I use the following code to set center and span to be shown in MapView. It should work.

MKCoordinateRegion region = {{0,0},{.5,.5}}; 
region.center.latitude = doubleLattitude; //user defined
region.center.longitude = doubleLongitude;//user defined
[mapView setRegion:region animated:YES];

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