s2sphere Python Module
Lat and Long
Precision
Convert a latitude and longitude from their integer forms (we prefer integers to floating points because the latter results in too large a loss of precision) to a level 30 cell ID. This conversion will result in a loss of precision by a few centimeters.
1
2
3
4
5
6
|
lat = 37791541
lng = -122390014
cellid = s2sphere.CellId.from_lat_lng(s2sphere.LatLng.from_degrees(lat/1e6,lng/1e6))
print(f"LatLong: {cellid.to_lat_lng()}")
|
LatLong: LatLng: 37.79154098519877,-122.39001395963571
The average size of a level 30 S2 cell is 0.74 cm2, level 20 S2 cell is 77.32 m2, and level 10 S2 cell is 81.07 km2.
Representation
Cell IDs can be represented as an integer or a compressed hexadecimal value that is referred to as a token.
1
|
print(f"Cell ID:{cellid.id()} Token:{cellid.to_token()}")
|
Cell ID:9260949427115031679 Token:8085806ff60c7c7f
The parent() function returns the parent cell for a given cellid. The smaller the cell level the larger the area covered by the cell.
1
2
3
4
5
6
7
8
|
def iterate_over_cells(cell):
while cell.level() >= 1:
yield cell
cell = cell.parent()
for x in iterate_over_cells(cellid):
print(f"Level: {x.level()} Cell ID: {x.id()} Min: {x.range_min().id()} Max: {x.range_max().id()} Token: {x.to_token()}")
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
Level: 30 Cell ID: 9260949427115031679 Min: 9260949427115031679 Max: 9260949427115031679 Token: 8085806ff60c7c7f
Level: 29 Cell ID: 9260949427115031676 Min: 9260949427115031673 Max: 9260949427115031679 Token: 8085806ff60c7c7c
Level: 28 Cell ID: 9260949427115031664 Min: 9260949427115031649 Max: 9260949427115031679 Token: 8085806ff60c7c7
Level: 27 Cell ID: 9260949427115031616 Min: 9260949427115031553 Max: 9260949427115031679 Token: 8085806ff60c7c4
Level: 26 Cell ID: 9260949427115031808 Min: 9260949427115031553 Max: 9260949427115032063 Token: 8085806ff60c7d
Level: 25 Cell ID: 9260949427115031552 Min: 9260949427115030529 Max: 9260949427115032575 Token: 8085806ff60c7c
Level: 24 Cell ID: 9260949427115028480 Min: 9260949427115024385 Max: 9260949427115032575 Token: 8085806ff60c7
Level: 23 Cell ID: 9260949427115016192 Min: 9260949427114999809 Max: 9260949427115032575 Token: 8085806ff60c4
Level: 22 Cell ID: 9260949427115065344 Min: 9260949427114999809 Max: 9260949427115130879 Token: 8085806ff60d
Level: 21 Cell ID: 9260949427114999808 Min: 9260949427114737665 Max: 9260949427115261951 Token: 8085806ff60c
Level: 20 Cell ID: 9260949427115261952 Min: 9260949427114213377 Max: 9260949427116310527 Token: 8085806ff61
Level: 19 Cell ID: 9260949427118407680 Min: 9260949427114213377 Max: 9260949427122601983 Token: 8085806ff64
Level: 18 Cell ID: 9260949427130990592 Min: 9260949427114213377 Max: 9260949427147767807 Token: 8085806ff7
Level: 17 Cell ID: 9260949427080658944 Min: 9260949427013550081 Max: 9260949427147767807 Token: 8085806ff4
Level: 16 Cell ID: 9260949427013550080 Min: 9260949426745114625 Max: 9260949427281985535 Token: 8085806ff
Level: 15 Cell ID: 9260949426208243712 Min: 9260949425134501889 Max: 9260949427281985535 Token: 8085806fc
Level: 14 Cell ID: 9260949422987018240 Min: 9260949418692050945 Max: 9260949427281985535 Token: 8085806f
Level: 13 Cell ID: 9260949410102116352 Min: 9260949392922247169 Max: 9260949427281985535 Token: 8085806c
Level: 12 Cell ID: 9260949427281985536 Min: 9260949358562508801 Max: 9260949496001462271 Token: 8085807
Level: 11 Cell ID: 9260949221123555328 Min: 9260948946245648385 Max: 9260949496001462271 Token: 8085804
Level: 10 Cell ID: 9260950045757276160 Min: 9260948946245648385 Max: 9260951145268903935 Token: 808581
Level: 9 Cell ID: 9260953344292159488 Min: 9260948946245648385 Max: 9260957742338670591 Token: 808584
Level: 8 Cell ID: 9260966538431692800 Min: 9260948946245648385 Max: 9260984130617737215 Token: 80859
Level: 7 Cell ID: 9261019314989826048 Min: 9260948946245648385 Max: 9261089683734003711 Token: 8085c
Level: 6 Cell ID: 9260808208757293056 Min: 9260526733780582401 Max: 9261089683734003711 Token: 8085
Level: 5 Cell ID: 9260526733780582400 Min: 9259400833873739777 Max: 9261652633687425023 Token: 8084
Level: 4 Cell ID: 9263904433501110272 Min: 9259400833873739777 Max: 9268408033128480767 Token: 809
Level: 3 Cell ID: 9277415232383221760 Min: 9259400833873739777 Max: 9295429630892703743 Token: 80c
Level: 2 Cell ID: 9295429630892703744 Min: 9223372036854775809 Max: 9367487224930631679 Token: 81
Level: 1 Cell ID: 9511602413006487552 Min: 9223372036854775809 Max: 9799832789158199295 Token: 84
|
Use the contains() method to determine if a cell ID is part of a given cell.
1
2
3
4
|
cell_tokens = ["80857fc","808581","808585c","808587","808f78c","808f7d","808f7f","808f804","808f81c","808f824"]
for x in cell_tokens:
print(f"{x} {s2sphere.CellId.from_token(x).contains(cellid)}")
|
1
2
3
4
5
6
7
8
9
10
|
80857fc False
808581 True
808585c False
808587 False
808f78c False
808f7d False
808f7f False
808f804 False
808f81c False
808f824 False
|