根据圆心经纬度和半径计算地图zoom level

最新推荐文章于 2025-07-21 13:47:08 发布

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最新推荐文章于 2025-07-21 13:47:08 发布

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分类专栏： Android 文章标签： zoom radius cen coordinate 地图

本文链接：https://blog.youkuaiyun.com/yinyignfenlei/article/details/54972557

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本文介绍了两种基于地理位置和精度范围来确定地图合理缩放级别的计算方法。方法一通过计算经度差值来推导出适合的地图显示比例，而方法二则通过所需的像素间距来计算出合适的缩放级别。

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方法一：

private double calZoomLevel(LatLng latLng, float radius) {

        double equatorLength = 40075004.0;
        double earthRadius = 6371229;

        double numerator = 1 + Math.pow((float)mMapView.getHeight()/(float)mMapView.getWidth(), 2);
        double denominator =  Math.pow(radius, 2);
        double distance = Math.sqrt(denominator/numerator);

        double longitudeDelta = (180 * distance)/(Math.PI * earthRadius * Math.cos(latLng.latitude * Math.PI/180));

        int width = DisplayUtil.dpFromPx(this, mMapView.getWidth());

        double tt = longitudeDelta * equatorLength * Math.PI / (180.0 * width);
        double zoom = 21 - Math.log(tt)/Math.log(2.0);
        return zoom;
    }

方法二：

private double calZoomLevel2(LatLng latLng, float radius) {

        // Equators length
        double equatorLength = 40075004.0;

        double distance = radius * 2;

        DisplayMetrics metrics = new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metrics);
        // Use min(width, height) (to properly fit the screen
        int screenSize = Math.min(metrics.widthPixels, metrics.heightPixels);

        // The meters per pixel required to show the whole area the user might be located in
        double requiredMpp = distance/screenSize;

        // Calculate the zoom level
        double zoomLevel = ((Math.log(equatorLength / (256 * requiredMpp))) / Math.log(2)) + 1;
        return zoomLevel;
    }