在Google静态地图API中获取矩形的图像

Question

我有两个LatLong点：矩形的左上角和右下角，我希望使用Google Maps API检索此矩形的卫星图像。

据我所知，由于缩放级别是一个整数，我可能无法得到这个确切的矩形，但如果我能得到一个更大的像素图，没有问题，只要我能够在latlong中计算像素图的边界框坐标。

由于像素大小是固定的（比如说640x640），而且我有它的中心，所以如何找到合适的缩放级别并计算像素图的边界框？

Answer 1

在旧版Google Maps API博客中找到一个提供函数CalculateBoundsZoomLevel的python引用。

源文件是here。

def CalculateBoundsZoomLevel(self, bounds, view_size): 
    """Given lat/lng bounds, returns map zoom level. 

    This method is used to take in a bounding box (southwest and northeast 
    bounds of the map view we want) and a map size and it will return us a zoom 
    level for our map. We use this because if we take the bottom left and 
    upper right on the map we want to show, and calculate what pixels they 
    would be on the map for a given zoom level, then we can see how many pixels 
    it will take to display the map at this zoom level. If our map size is 
    within this many pixels, then we have the right zoom level. 

    Args: 
     bounds: A list of length 2, each holding a list of length 2. It holds 
     the southwest and northeast lat/lng bounds of a map. It should look 
     like this: [[southwestLat, southwestLat], [northeastLat, northeastLng]] 
     view_size: A list containing the width/height in pixels of the map. 

    Returns: 
     An int zoom level. 
    """ 
    zmax = 18 
    zmin = 0 
    bottom_left = bounds[0] 
    top_right = bounds[1] 
    backwards_range = range(zmin, zmax) 
    backwards_range.reverse() 
    for z in backwards_range: 
     bottom_left_pixel = self.FromLatLngToPixel(bottom_left, z) 
     top_right_pixel = self.FromLatLngToPixel(top_right, z) 
     if bottom_left_pixel.x > top_right_pixel.x : 
     bottom_left_pixel.x -= self.CalcWrapWidth(z) 
     if abs(top_right_pixel.x - bottom_left_pixel.x) <= view_size[0] \ 
      and abs(top_right_pixel.y - bottom_left_pixel.y) <= view_size[1] : 
     return z 
    return 0