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Python3 QuadKey/Tiling
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from math import ( | |
pi, | |
cos, | |
sin, | |
log, | |
atan, | |
exp | |
) | |
__EARTH_RADIUS = 6378137 | |
__MIN_LAT = -85.05112878 | |
__MAX_LAT = +85.05112878 | |
__MIN_LON = -180.0 | |
__MAX_LON = +180.0 | |
def __clamp(n: float, min_value: float, max_value: float) -> float: | |
assert min_value <= max_value | |
return min(max(n, min_value), max_value) | |
def __map_size(level_of_detail: int) -> int: | |
return (256 << level_of_detail) | |
def ground_resolution(latitude: float, level_of_detail: int) -> float: | |
latitude = __clamp(latitude, __MIN_LAT, __MAX_LAT) | |
return (cos(latitude * pi / 180) | |
* 2 | |
* pi | |
* __EARTH_RADIUS | |
/ __map_size(level_of_detail)) | |
def map_scale( | |
latitude: float, | |
longitude: float, | |
level_of_detail: int, | |
screen_dpi: int) -> float: | |
return ground_resolution( | |
latitude, | |
level_of_detail) * screen_dpi / 0.254 | |
def pixel_xy_to_latlon( | |
pixel_x: int, | |
pixel_y: int, | |
level_of_detail: int) -> (int, int): | |
map_size = __map_size(level_of_detail) | |
x = (__clamp(pixel_x, 0, map_size - 1) / map_size) - 0.5 | |
y = 0.5 - (__clamp(pixel_y, 0, map_size - 1) / map_size) | |
return ( | |
90 - 360 * atan(exp(-y * 2 * pi)) / pi, | |
360 * x | |
) | |
def latlon_to_pixel_xy( | |
latitude: float, | |
longitude: float, | |
level_of_detail: int) -> (int, int): | |
latitude = __clamp(latitude, __MIN_LAT, __MAX_LAT) | |
longitude = __clamp(longitude, __MIN_LON, __MAX_LON) | |
x = (longitude + 180) / 360 | |
sin_latitude = sin(latitude * pi / 180) | |
y = 0.5 - log((1 + sin_latitude) | |
/ (1 - sin_latitude)) / (4 * pi) | |
map_size = __map_size(level_of_detail) | |
return ( | |
int(__clamp(x * map_size + 0.5, 0, map_size - 1)), | |
int(__clamp(y * map_size + 0.5, 0, map_size - 1)), | |
) | |
def pixel_xy_to_tile_xy( | |
pixel_x: int, | |
pixel_y: int) -> (int, int): | |
return ( | |
pixel_x / 256, | |
pixel_y / 256, | |
) | |
def tile_xy_to_pixel_xy( | |
tile_x: int, | |
tile_y: int) -> (int, int): | |
return ( | |
tile_x * 256, | |
tile_y * 256, | |
) | |
def tile_xy_to_quadkey( | |
tile_x: int, | |
tile_y: int, | |
level_of_detail: int) -> str: | |
quad_key = '' | |
for i in range(level_of_detail, 0, -1): | |
digit = 0 | |
mask = 1 << (i - 1) | |
if (tile_x & mask) != 0: | |
digit += 1 | |
if (tile_y & mask) != 0: | |
digit += 2 | |
quad_key += str(digit) | |
return quad_key | |
def quadkey_to_tile_xy(quad_key: str): | |
tile_x = 0 | |
tile_y = 0 | |
level_of_detail = len(quad_key) | |
for i in range(level_of_detail, 0, -1): | |
mask = 1 << (i - 1) | |
c = quad_key[level_of_detail - i] | |
if c == '0': | |
pass | |
elif c == '1': | |
tile_x |= mask | |
elif c == '2': | |
tile_y |= mask | |
elif c == '3': | |
tile_x |= mask | |
tile_y |= mask | |
else: | |
raise RuntimeError('Invalid quad key character: %s' % c) | |
return ( | |
tile_x, | |
tile_y, | |
level_of_detail, | |
) |
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