最近这几天因为Pokemon Go S2 的Pokestop 发现，引爆了 Reddit 大洗版，到底什么是S2
，目前有发现了什么规律，而知道这些规律倒底又有什么用。
★ S2 简易说明
(必须用 Google Chrome 开启地图)
http://s2map.com
https://s2.sidewalklabs.com/regioncoverer/
大家想到地图的座标，就会想到说是经度纬度。
所以通常譬如台北就是 25.03739° N, 121.5635° E
但是Google 还有出一种座标，叫做 S2 Library。
http://i.imgur.com/3IBAfqj.jpg
大家都知道地球是一个球型的，把球放在一个正方体，就有六个面了。这六个面我们可以编
号1-6，这就是 S2 Level 0。
把每一个面从宽跟高的正中间分成两半，会变成四个小方格 (田)，这个就是 S2 Level 1。
编号就是他原始Level 0 的编号再编1-4。所以Level 0 的编号 5 会有四个小孩分别是 51
、52、53、54。
再把Level 1 的方格切成田，就会得到Level 2。譬如切开了54得到了541、542、543、544
。
http://blog.christianperone.com/wp-content/uploads/2015/08/level_15_8.png
所以Level 越高，所包括的面积就越来越小了。 Google 把地球划分为 Level 30 刚刚好所
有的编号可以塞进一个64位元，这样就比经纬度需要两个64位元的省空间，又好算。
通常一个正方体的面英文是 Face ，但是在S2 Library 里面称为 Cell ，Cell 这个字在英
文代表的是整整齐齐划分一格格的其中一个格，所以在中文的翻译就有细胞、牢房、电池
etc，我不知道S2 Cell 中文的正确翻译，以下简称为‘区’。
那么S2 的每个层级的区到底有多大呢?
Level 30 的区最小有 0.48 公分平方
http://blog.christianperone.com/2015/08/googles-s2-geometry-on-the-sphere-cells-
http://tinyurl.com/keg9x4w
http://blog.christianperone.com/wp-content/uploads/2015/08/s2_cell_area.png
★ 主宰 Pokemon Go 世界的 S2 规矩
Pokemon GO 很多都是程式自动跑，为了确认分布很均匀，很多生成都跟S2 层级节节相关来
确认平均分布，还有程式计算。
Reddit 上有了详细的分析，下面简单翻译一个 Reddit 懒人包
S2 cells & GO: the various levels applied that we're aware of atm
https://www.reddit.com/r/TheSilphRoad/comments/7ow4ix/s2_cells_go_the_various_le
http://tinyurl.com/yawd76gj
u/Uraxor
By now even occasional Silph traveler must have noticed that s2 cells are
becoming big and dictate a whole lot of rules applied behind the scenes of PoGo.
(Cells explanation by Calmarius.)
最近SilphRoad 讨论区关于 S2 区的讨论大爆炸，大家发现说 Pokemon Go 很多的程式计算
都跟这个有关系，可说是 PokemonGo 世界的主宰。
Since it's kind of starting to make my head hurt I thought I'd put together a
list of the various levels, where are they applied and where to look for some
more info on that particular topic. Please take note that some topics are
rather old but despite that many could use further research - if this summary
inspires you to pick up the work, go for it!
Disclaimer: credits go to OPs, obviously :)
然后我的头已经被这些文章给搞混了，所以做了个简易列表，下面有些文可能都很旧了，但
可能还有更多需要研究更深入的地方。
level 6 - geoblocking (NKorea etc.)
封锁 (譬如北韩没有开放Pokemon Go)
https://www.reddit.com/r/TheSilphRoad/comments/6xnv4j/compiled_information_on_th
http://tinyurl.com/yc8va4fn
level 6 - former Beasts distribution
以前神兽的分布
https://www.reddit.com/r/TheSilphRoad/comments/6xnv4j/compiled_information_on_th
http://tinyurl.com/y9g52njt
level 9 - regionals distribution (WIP)
地区限定的分布
https://www.reddit.com/r/TheSilphRoad/comments/5nxdgj/regional_pokemon_distribut
http://tinyurl.com/ybol4y64
level 10 - Pokemons' "caught" location (includes raid bosses)
宝贝在哪里被抓到的
https://www.reddit.com/r/TheSilphRoad/comments/5n4z9p/why_is_your_capture_locati
http://tinyurl.com/y9u6d2zp
level 10/11 - weather (inconclusive atm)
疑似天气分界，还没有确认到底是10还是11
https://www.reddit.com/r/TheSilphRoad/comments/7m9qgo/extreme_weather_confirms_s
http://tinyurl.com/ydgoc8ff
level 12 - Ex-Raids distribution
VIP 团体战的分布
https://www.reddit.com/r/TheSilphRoad/comments/7m111i/surprising_observation_of_
http://tinyurl.com/ybm9l9s3
level 14 - possible biomes (WIP) + 1 more post supporting level 14 + another
post inclining towards level 12
各系分布 (譬如海边电系增加)
https://www.reddit.com/r/TheSilphRoad/comments/5s43ic/analysis_of_the_electric_b
http://tinyurl.com/yazvmmwx
level 14 - gyms placement
道馆位置选择
https://www.reddit.com/r/TheSilphRoad/comments/7ojtep/this_is_what_it_looks_like
http://tinyurl.com/y76nhue6
https://www.reddit.com/r/TheSilphRoad/comments/7p0ggv/finding_out_the_rules_of_g
http://tinyurl.com/y7ja3lte
level 15 - blocked (e.g. military) areas - seems to be IG display only, spawn
points are likely to be controlled by OSM
军方基地地图封锁
https://www.reddit.com/r/TheSilphRoad/comments/7oz8fn/s2_cells_map_blocking_at_l
http://tinyurl.com/y6v2rz5e
level 16 - IG world display (gyms, stops)
地图上的道馆与补给站显示
https://www.reddit.com/r/TheSilphRoad/comments/7iu2bs/overworld_map_gymsstops_an
http://tinyurl.com/y9d3kbd2
level 17 - stops placement
补给站位置
https://www.reddit.com/r/TheSilphRoad/comments/7ou3j0/i_just_found_out_that_nian
http://tinyurl.com/yddtlc78
图例
https://i.imgur.com/7E94CN5.jpg
https://i.imgur.com/l7u0jlq.jpg
http://www.brandonenright.net/~bmenrigh/pogo_s17_stops_overlay.png
level 20 - spawns placement
怪产生点
https://www.reddit.com/r/TheSilphRoad/comments/5qrhe0/oh_nodes_my_final_research
http://tinyurl.com/yabvyxg2
图例
https://www.reddit.com/r/TheSilphRoad/comments/7ojtep/this_is_what_it_looks_like
https://i.redd.it/6b4b5xgstg801.jpg
level 20 - gyms' location - important for determining Ex-Raids eligibility
道馆标签
https://www.reddit.com/r/TheSilphRoad/comments/7ojuoi/how_to_determine_which_gym
http://tinyurl.com/y937bjpt
level 20 - eggs pickup & hatch location (sorry couldn't find link)
捡蛋跟孵蛋地点
★ 知道了又如何?
所以知道了这些又怎么样呢?
补给站的规则是
1) 只有 Ingress Level 10 以上的玩家可以申请Portal
2) 但是Portals 必须间格20 米，如果低于20公尺是会被秒驳回的。
3) 最近 PokemonGo 不定时的会 synch Ingress 的Portal资讯，不是每个Ingress
Portal 都会成为 PokemonGo 的补给站或是道馆。除了赞助商的补给站道馆外，每个
Level 17 的S2 区只能有一个补给站/道馆。
这代表了如果你家附近的补给站很少，或著是你想要弄一个4花点的话，你就可以看着 S2
Level 17 的地图，尽量在交接处申请 protals 像下面这个图一样，但是要记得如果这个区
已经有了补给站了，你申请再多的Protals 都不会变成补给站。 如果补给站被移除的话，
同一个区里的Protal 就会变成新的补给站。
https://i.imgur.com/7E94CN5.jpg
你如果申请补给站的座标不对，被检举了，然后座标改正之后刚刚好不小心的到了隔壁区，
而隔壁区已经有了补给站了，那么很抱歉这个补给站就会消失。
如何增加道馆
我翻译一下发现道馆数目跟补给站数目关系的人的文章
https://www.reddit.com/r/TheSilphRoad/comments/7p0ggv/finding_out_the_rules_of_g
r/pr0n-clerk
http://tinyurl.com/y9arf6kg
I made my own posting on this exact same thing, but took too long typing it
out. Going to delete my original posting and just put this here. Basically came
to the same conclusion you did.
First off, credit goes to /u/hnedka for finding this information. This was
first talked about in a comment here but I wanted to bring more light to the
subject. Here is my original post and finding below.
I have leveled up in Ingress and noticed a lot more gyms were being added to
the areas I play as I add more portals to Ingress. It seemed pretty random
until looking into s2 cells and seeing how everything fit together.
我最近在Ingress 升等，然后发现说我玩 Ingress 的区域随着我一直加Portals，有越来越
多的Pokemon Go 道馆，这原本看起来没什么规律的，直到我看了 S2 的地图才恍然大悟。
The basic findings is that the world of gyms is divided up in size 14 s2 cells.
If you find any s2 cell with only one pokestop in it, then add another portal,
then once that portal converts over then one of the two will become a gym. I
had one s2 cell with only one pokestop, so I added another portal. Once it came
over, the old pokestop became a gym. I had another s2 cell with zero stops in
it, so I added two portals at churches in it. They came over at the same time
and one was a stop and one was a gym.
简单的来说如果你看到 S2 Level 14 的区里只有一个补给站，那么你只要加一个 Portal
，当Portal 转成 Pokemon Go 的时候，这两个的其中一个就会成为道馆。有次S2 区只有一
个补给站，我加了个 Portal ，那个新的Portal 转成了补给站，旧的补给站就成为了道馆
。还有次有一个S2 区没有补给站，那我就加了两个 Portals 在教堂，两个同时转过来，其
中一个是补给站，另一个就成了道馆。
The next gym threshold seems to be 6 stops/gyms. I had a s2 cell with 1 gym and
4 other stops in it. I went and added a portal to that area, and the portal
came over as a pokestop and an old one converted into a gym.
下一个天花板是六个补给站。我有个S2区有一个道馆跟四个补给站，我加了个protal，下次
转过来的时候，那个新的变成了补给站，而某一个旧的补给站成为了道馆。
I have not discovered the threshold for 3 gyms in an area yet, but will
continue looking into it.
This means that if you have the ability, or know of someone with the ability,
to add portals via Ingress then you can focus your work on adding gyms if you
want. You can put down a size 14 s2 grid and look for areas that only have one
or five pokestops in it. Once you find all the cells that fit that criteria,
then you can look for portals candidates in those cells so that you can add
seven gyms every two weeks. This is great for adding gyms to park areas to
increase the number of EX raids that go out into the world.
这代表了如果你有这个能力，有认识某人可以在 Ingress 加Protals ，那么你可以专注于
加你想要的道馆，你只要看着 S2 Level 14 的地图，寻找只有一个或五个补给站，那么就
找适合申请 Protal 的地点 (记得必须是间格 20米，一个S2 Level 17 只能有一个补给站)
，那么你就可以成功的增加道馆了，一个礼拜可以申请七个。增加了公园的道馆数目就增加
了发卷的VIP团体战的道馆了 (尤其是明明是公园却没有道馆的地方)。
In summary, using size 14 s2 cells.
0-1 -> 0 gyms
2-5 -> 1 gym
6-19 -> 2 gyms
20-34 -> 3 gyms (this limit needs further researched)
35+ -> 4 gyms (this limit needs further researched)
(一个Level 14 里有64个Level 17)
以上是目前的推测，到目前为止没有找到一个Level 14 密集到可以有5 个道馆的地方，所
以不知道5个道馆需要的补给站数目。