geocat.py 文件源码

def _get_extents(self, proj, res, lon_arr, lat_arr):
        p = Proj(proj)
        res = float(res)
        first_good = self._first_good_nav(lon_arr, lat_arr)
        one_x, one_y = p(lon_arr[first_good], lat_arr[first_good])
        left_x = one_x - res * first_good[1]
        right_x = left_x + res * lon_arr.shape[1]
        top_y = one_y + res * first_good[0]
        bot_y = top_y - res * lon_arr.shape[0]
        half_x = res / 2.
        half_y = res / 2.
        return (left_x - half_x,
                bot_y - half_y,
                right_x + half_x,
                top_y + half_y)