zoom.py 文件源码

def pixel_to_lonlat(self, px, zoom):
        "Converts a pixel to a longitude, latitude pair at the given zoom level."
        if len(px) != 2:
            raise TypeError('Pixel should be a sequence of two elements.')

        # Getting the number of pixels for the given zoom level.
        npix = self._npix[zoom]

        # Calculating the longitude value, using the degrees per pixel.
        lon = (px[0] - npix) / self._degpp[zoom]

        # Calculating the latitude value.
        lat = RTOD * (2 * atan(exp((px[1] - npix) / (-1.0 * self._radpp[zoom]))) - 0.5 * pi)

        # Returning the longitude, latitude coordinate pair.
        return (lon, lat)