電力座標與２度ＴＭ座標的關係

Taiwan Power Company Grid and TM-2 Grid Relationship

• ENGLISH ONLY auto-stripped version of
• 中英版 Chinese+English version.

圖 1999 photo: 作者被「發現」偷抄電力座標 author "caught red-handed" copying coordinate (B)6737 AE90. 台灣座標曾為大禁忌。 Coordinates were once a big secret in Taiwan. 原來你視為障礙的桿子及箱子， 沒想到多年來個個都印了。 台北市和平東路 Heping E. Rd., Taibei.

座標就在你身邊－怎樣利用路邊電線桿及電線箱算出２度ＴＭ座標 Your coordinates are right there on the nearest electric pole -- How to use Taipower's pole and box numbers to get your TM-2 degree coordinates

作者簡介：本文作者為美國人現居住在臺中縣東勢鎮， 他偶然發現自己家附近的電線桿境然有編號， 經過他仔細觀察，電力公司電桿的號碼特別多，而且似乎有規則可尋。 在美國念大學主修地質學的他，憑藉對地圖的興趣， 竟然從電線桿編號找出確實座標，甚至連電線箱也可以找出座標。 他說， 在台灣不必攜帶衛星定位系統，憑著電線桿及電線箱可以定出座標， 其誤差只有十米，市區內甚至還可達到一米。

與親朋好友一起出遊，我喜歡當導遊，並玩一種「開小路」的遊戲， 坐在車內當指揮，我不選擇走大馬路，而樂於走與大馬路平行的小路， 心想，只要有路，雖然是小路，終究能憑藉著地圖到達目的地， 跟著我的朋友以為我是小路亂竄。 有一次出遊，手指壓著地圖上現在的位置，隨著車子行走的方向彎沿著， 為了充分享受樂趣，隨性撥放繞舌歌曲，手指也跟著動了起來， 直到了一個交叉路口，開車的朋友問我「怎麼轉？」， 而我卻慌張的拿著地圖亂翻，朋友們受不了，轉而尋問路人， 我輸了。可惜當時我沒想到，其實「現在位置」就在路邊， 路邊台電的電線桿牌子及開關箱上就有， 不必攜帶ＧＰＳ全球衛星定位系統就可以知道自己現在的位置，不會再迷路了。 台電的電線桿牌及開關箱我笑稱為窮人的ＧＰＳ， 阿Ｑ我說高樓旁的ＧＰＳ也派不上用場，且ＨＢＯ不是每年都有斷訊危機？ 也許ＧＰＳ也會有這一天，但電線桿／箱還是老神在在的。

國人可不必再根據亂七八糟的門牌號碼找位置了， 就連不懂中文的外國人也能憑電線桿／箱來旅遊。

Understanding coordinates on utility pole numbers, a Taiwanese example

Whereas the reader is surely a map reading and GPS smarty or expert; and Whereas the reader probably has ignored all the little funny numbers on the utility poles and boxes that have surrounded you for the first half of your life; and Whereas I have reached great fame and glory by decoding these numbers here on Taiwan, a sort of poor person's GPS; (plus, next time non-geographically oriented friends invite you to their ranch, just ask them to read you a pole, you'll be there in no time.) Therefore, it's time for the reader to investigate the issue! I mean how are you going to understand the rhythms of the universe when you don't even understand what your front yard's utility pole is trying to tell you, Holmes. (Plus, one day when your or the Government's GPS batteries run out, where's your backup system? I've got mine. (At least where there are roadside utility poles to read.))

To get started, take a look around yourself, e.g., here on Taiwan the telephone poles don't say much, but the electric company's poles and switching boxes have lots of juicy numbers to decode. First plot a few on paper with their relative positions and see if you can decode them on your own. When I first tried, I got the Y coordinate right but X was always off... I gave up and marched into the local electric company service center and took a look at their maps... ah-ha, a rectangular grid! You see, their map paper is rectangular and the first part of the pole number is a map number...(How brilliant, there should be a law, every county and state's borders should be adjusted to 8:5 rectangular proportions to fit standard paper sizes, and the ideal eye-comfortable map proportions.)

Dec. 2001: I swear within two seconds I can already put my finger on where I am on the map, whilst your mom still hasn't got her GPS out of the holster of her cowboy pants. Disclaimers:

1. My power company's poles have got coordinate information on each roadside pole number plate. Check your utility poles...
2. My pals made it into an atlas. [However adding the utility co.'s system to a regular map is easy.] Grid conversion computation has thus been already done before we leave home.
3. I only read the first line of the pole coordinates, for a thumb size 800 x 500 m. fix on their 1:50000 atlas.
4. Look mom, no batteries.

為了紀念限閱地圖時代，我特別拍些 「間諜被發現正在抄寫座標」的照片。 經由以下說明，就可以瞭解，其實你所在位置座標就在你我的身邊， 原來你視為障礙的桿子及箱子， 沒想到多年來個個都印了原來大禁忌的座標。

I use the numbers of the Taiwan Power Company's poles and boxes to get my coordinate position, a sort of "poor man's GPS". You too can be a utility pole whiz -- check your poles!

Taiwan Power Company's grid numbers, seen on many electric poles and switching boxes throughout Taiwan, are one way of describing your geographical position. Latitude and longitude is another way, but the major way used on government maps here is the TM-2 system (TWD67). Let's see how it relates to the TaiPower's system. Perhaps it is possible to navigate around Taiwan just using these pole and box numbers, without having to learn Chinese, or wait for the government to hurry up and please accept Hanyu Pinyin romanization of street signs. By the way, the below calculations are unnecessary if one makes or buys maps with the utility company's grid numbers already added. TM-2 stands for Transverse Mercator projection, focused for coverage over 2 degrees of longitude, e.g. 120 to 122 east.

, 實例 real example

Figure 1. Looking at the number plate with coordinates G8150 HD78 [call this GPPQQRSTU[VW], G is a 80 x 50 km rectangle, (Taiwan is divided into several of these rectangles.

PP increments by 1, every 800 m eastward,  00-99
QQ increments by 1, every 500 m northward, 00-99
R  increments by 1, every 100 m eastward,  A=0...H=7
S  increments by 1, every 100 m northward, A=0...E=4
T  increments by 1, every 10  m eastward,  0-9
U  increments by 1, every 10  m northward. 0-9

In equipment-dense cities often there are additionally:

V increments by 1, every 1 m eastward,  0-9
W increments by 1, every 1 m northward, 0-9

(Hmmm, one-meter precision, bet your mom's GPS can't do that.)

我們首先看看台電公司電線桿的牌子（如圖）， 該牌子的下兩行就是座標（這是舊電線桿牌子所沒有 的）， 經過簡單的換算， 我們可以將牌子上座標換算成橫麥卡脫投影２度ＴＭ座標ＴＷＤ６７， 這也是許多台灣政府出版地圖所使用的座標系統以下簡單的分析電力座標所分別代表的意義。

Let's take a deeper look at that TaiPower pole number plate, mine infact. Again, the last two lines of that plate, G8150 HD78, are the coordinates. We can convert them to TM-2 coordinates, version TWD67, for use with government maps, GPS, etc. Let's take a look at the meaning of each of those numbers.

如附圖二所示， 以東西寬八十公里， 南北長五十公里為範圍， 將台灣劃分如圖上區域並以英文字母代表所在位置大區域， 如筆者所居住的台中縣東勢鎮位置為Ｇ大區。

Figure 2. As we see, TaiPower has divided Taiwan into 80 km wide, 50 km tall lettered rectangular sectors. For instance, the author lives in Taizhong County, Dongshi Township, which lies in the G sector.

他區 Other areas: I: 無陸地 underwater; S: 馬祖 Mazu; U: 只有約３０公頃面積 only about 30 hectares; X, Y: 澎湖 Penghu; Z: 金門 Jinmen.

Ｇ大區共分為一萬個 配電圖圖號， 每張圖東西寬８００公尺， 南北長５００公尺。 Ｇ大區最西側的Ｘ座標為１７００００公尺東， 最南側的Ｙ座標為２６５００００公尺北， 而Ｇ大區第８１５０圖區西側之Ｘ座標 （如圖 三）為１７００００＋８１＊８００＝２３４８００公尺， 南側之Ｙ座標為２６５００００＋ ５０＊５００＝２６７５０００公尺， 這就是圖一電力座標Ｇ８１５０所代表的意義。

Figure 3. This G sector is divided up into 10000 charts back at the electric company office. Each covers 800 * 500 meters. The west edge of sector G is at x=170000 meters East. The south edge is at y=2650000 meters North. The west edge of the 8150th chart is at x=170000mE + 81 * 800m = 234800mE, the south edge is at y=2650000mN + 50 * 500m=2675000mN. Now we understand the meaning of G8150.

另Ｇ大區第８１５０號圖又細分東西ＡＢＣＤＥＦＧＨ各１００公尺， 南北ＡＢＣＤＥ各１００公尺， 由圖四可見， 電力座標ＨＤ所代表範圍的西南角即距Ｇ區第８１５０圖西側７００公尺， 南側３００公尺的位置。 （註：Ａ＝０， Ｂ＝１００， Ｃ＝２００．．．）

Figure 4. OK. This 8150th sector is further given ABCDEFGH grids, going west to east, each 100 meters apart; ABCDE grids south to north, each 100 meters apart.

As can be seen, power co. grid HD's area's southwest corner lies 700 meters east of the west edge of box 8150, and lies 300 meters north of the south edge of box 8150. Note, A=0, B=100, C=200...

座標７８所代表範圍的西南角即ＨＤ區西側往東７＊１０公尺， 其南側往北８＊１０公尺。 （如圖五）

Figure 5. Next, the "78" portion of the grid has its southwest corner at 7*10=70 meters east of the west edge of area HD, and 8*10=80 meters north of the south edge of HD.

綜合以上敘述， 電力座標Ｇ８１５０ ＨＤ７８的２度ＴＭ座標分別為

Summing up the above, power co. pole/box grid number G8150 HD78's TM-2 grid value is:

 170000+81*800+(8-1)*100+7*10 =  235570 meters East  米東
2650000+50*500+(4-1)*100+8*10 = 2675380 meters North 米北

所細分圖區雖然還是１０＊１０公尺大的區域， 可是對於出外的遊客而言， 已經可以精準的得知自 己目前所在的位置。 在都市地區， 因電線桿∕箱的密度較高， 我們還可找到加印個位數字的， 第一 數字：米東， 第二：米北；例：Ｇ８１５０ ＨＤ７８１２。 其精度則達一米， （阿Ｑ我說）比單 一ＧＰＳ衛星定位儀測出的座標值還準確（另外， 電桿∕箱密的地方， 房子也高， 此時ＧＰＳ更難 發揮功效了）。

The smallest unit of our grid is still a 10*10 meter square, but that ought to be small enough for, say, a traveler to find his spot on maps. In cities, where electrical line density is high, we can often find box and pole labels with an additional two digits, e.g. G8150 HD7812, which means add 1 meter east and 2 meters north to the above result. Indeed, the dense part of cities have tall buildings, hindering Global Positioning System (GPS) reception, so with one meter accuracy, it seems we do better than the basic hand held GPS in this case [?!smile].

圖：為了增加讀者的挑戰， 還有早期環式桿牌會落字； 新牌亦可能曬久曬壞。 圖中小手指拉。 Photo: To increase the challenge, there are also old style pole band labels with numbers often fallen out, here tugged with my pinky finger.

瞭解電線桿∕箱牌子的意義後， 若到朋友山寮做客， 問他電線桿∕箱牌號即可， 門牌號碼不必提， 當然， 也請他一併告訴你附近另一、兩支桿號， 怕萬一一支是連桿帶牌由外地移來， 另外忘了帶指 北針， 且找不到北極星時， 還可利用二支電線桿的相對位置來定出北方呢！

In conclusion, next time you go to a friends mountain top hideaway, just ask them their electric pole or box number --- no need for confusing road addresses. Of course you had better ask them for a couple more nearby label numbers too, in case there is a pole that has been transplanted along with its old label. If you forget to bring a compass, or can't find the north star, the relative positions of two poles/boxes can be used to compute north, south, east, west too!

[In case you haven't seen me mention it elsewhere, be forewarned that there are still large areas of Taiwan with old poles that don't carry coordinate information. The boxes all do but they are mainly only in the cities.]

找編號有時要看水泥基礎 Sometimes you must check the cement base to find coordinates

所有我見過的箱子有座標， 但有時要看其水泥基礎。 桿子要看地方， 譬如台中縣市不錯但汐止、南投都舊牌無座標；到東、南部更需要心理準備。 有時好像地方執行總公司的更新計畫不努力， 可提星他們。

All of the switch boxes I've seen have grid numbers, but sometimes you have to look at the cement foundation. The poles on the other hand vary. Some districts only have older poles whose labels lack coordinates. Or maybe the local administrator isn't using the new scheme yet -- let them know.

多餘的號碼 Superfluous numbers

另外，Ａ１２３４ ＢＣ５６７８ 常縮寫成 Ａ１２３４ ＢＣ５６， 有時甚至 １２３４ ＢＣ５６ ．．． 我去彰化市，注意到其箱子有如 Ｇ４０２８Ｃ ＢＣ２３－ＰＤ 的編號， 前邊多一個 Ｃ， 後面多個 ＰＤ。 這不過是多一個例子：讀者必須隨時準備遇到各種「加值」編號。 這次牛肉還是 Ｇ４０２８ ＢＣ２３，而額外的 ＰＤ 不過是裝置型式代號，如「亭置式」。至於第一個 Ｃ，對我們來講是多餘，但因為讀者一定好奇，說明如下：第 ４０２８ 圖能再分四張更細的圖（可見垂直值Ｃ５以北屬於Ａ ，Ｂ 細圖區，而ＢＣ２３的ＸＣＸ３南於ＸＣＸ５（Ｘ為變數），四塊交叉點於 ＥＣ０５００）。

Additionally, A1234 BC5678 is mostly abbreviated A1234 BC56, and sometimes even 1234 BC56, or how about in Zhanghua, where one sees e.g. G4028C BC23-PD. An extra C in front and PD at back. Here the PD refers to the type of switching etc. device installed -- ignore it. The C can also be ignored. It refers to a more detailed set of maps at the electric company office -- a block of four centered on EC0500.

我於東勢看到 ＧＥ９８００ Ｇ７６６６。 這不過是 Ｇ７６６６ ＧＥ９８（００）。 In Dongshi, I saw GE9800 G7666. This of course is just G7666 GE98(00). 在關渡有人看到箱子漆 「圖號Ｂ５７５８ 座標ＤＡ０４」。 In Guandu folks have spotted a box painted with Chinese "Tu2hao4 (map number) B5758 Zuo4biao1 (coordinates) DA04".

另請注意， 我們講的是電力公司的設備， 非電信等單位的， 高壓鐵塔也無座標， 可免攀爬。

Also note we are talking about electric company equipment, not telephone poles, etc., and not high voltage towers, so don't climb them.

大家也許很好奇，除了電力公司電線桿／箱牌子外， 電力公司還有高壓鐵塔，他們的牌號只用「起點－終點１，２，３．．．」 等簡單編號，並無座標意義。中華電信的桿子雖然也只是 「某某枝１，２，３．．．」 但仍可作尋路的指標來準備地圖以便於訪客在山區不迷路。 最後一類是中華電信的箱子， 如ＬＭ１２３４屬黎明局（黎明交換機服務範圍）， 至於１２３４，頂多可以說１２００ 至１２９９在地緣上大概比較集中， 同樣１０００－１９９９大概都在同一個社區，但都是受當地地理、 交通影響，並非有座標規則的意義。 當然也有時候前邊兩個字母不寫等等挑戰。

路燈編號 Street lamp numbers

於台中市我遇到些路燈，編號為 In Taizhong City I ran across some street lamps numbered

00595 25G6349FE94
00597 25G6349FE90
00598 25G6349FD88
00599 25G6349FD77

左者僅沿路編號， 右者則我們熟悉電力座標， ２５者待查。 At left is merely a serial number increasing lamp to lamp along the road. At right is our familiar TaiPower grid number. The 25 awaits further investigation.

地圖集 Atlases

已套電力座標 With TaiPower grids

• 上河（Sunriver）

程式 Programs

已有不少電力座標程式。 Already there are many TaiPower grid programs.

$ echo G8150 HD7812|./taipowergrid|./xylonlat
##1 G8150 HD7812
#1 235571 2675382
TWD67:
235571 2675382
120.857978243173 24.1836801864713
120d 51m 28.72s 24d 11m 1.25s
TWD97:
236399 2675176
120.866138239638 24.1819144465914
120d 51m 58.10s 24d 10m 54.89s

請現在參考 Please now see Taiwan 衛星定位系統 GPS and 座標轉換 TWD67, TWD97, WGS84 coordinate transformations.

澎湖 Penghu

澎湖的 ｘ＝２５００００ｍ 線為東經１１９度， 於台灣島不同。 Penghu uses 119 east longitude as x=250000m.E., unlike Taiwan.

+------+2664000
|  X   |
|      |
+------+2614000
|  Y   |
|      |
+------+2564000
275000 355000

金門 Jinmen

金門使用ＵＴＭ ６度分帶座標系統（其中央子午線為東經 １１７度，平移５０００００公尺）， （本文所有縱座標均以赤道為原點）。 Jinmen uses 117 east longitude as their x=500000m.E. definition. (This is a 6 degree wide "UTM" grid area.)

金門有兩個同名為Ｚ大區。 因金門地小， 兩Ｚ區不衝突。 我們的程式仍能處理。 Jinmen has two sectors both named "Z", which don't conflict as Jinmen is small. Our program can still deal with it.

+------a------+2725800
|  Z   |  Z   |
|      |      |
+------+------+2675800
552700 632700 712700

　Let's convert point 來換算點 "a" :

$ proj -le|grep -w intl #猜 Guessing
intl a=6378388.0 rf=297. International 1909 (Hayford)
$ echo 632700 2725800|proj -I +proj=utm +lon_0=117 +ellps=intl
118d18'40.019"E 24d38'25.43"N

至 To WGS84

2007.9: 老了，忘了怎轉 I'm old and forgot how to convert to WGS84. 可試 However let's try:

$ programs/taipowergrid file_full_of_Z_lines|perl -alnwe \
'if(/^\d/){$_=join " ",$F[0]+275,$F[1]+5};print if /./'|
proj  -I -f %.6f +proj=utm +lon_0=117
#1 Z0156 HD3215
118.326956 24.444907
#2 Z0063 DC3879
118.315504 24.476288

烏坵 Wuqiu

未知 Unknown.

馬祖 Mazu

S 區 area.

2007/9 Miller Liu reporting: 2007/9:"1954北京座標系, 高度採1985中國高程基準, 因此方格座標一定是Gauss-Kruger六度分帶" knowledge under construction.

製圖緣工具：每公里加電力座標 Tool for map edges: each kilometer's TaiPower grid number: existing map grids: output; source: download from index page.

Note that I am not attempting to discuss the merits of some of the design choices made by the power company here. I'm only doing a cursory introduction to it. Note however that 8:5 (of the 800 x 500 m. grid) is often cited as ideal dimensions for ease of use of atlases.... Actually they chose it to match the size of the chart paper available, I believe. 之所以選擇８００公尺 ＊５００公尺為區域長寬是為了配合台電公司使用紙張長寬， 正好也是地圖學上所謂黃金比值８比５， 該比例之長寬地圖於視覺上最好。

And, with a 1 minute pencil addition to a topo map, it's like God(tm) came down and hung those B-5, A-3... kiddie map index numbers on every pole, for our convenience... if you know what I mean.

This road lacks a name, however its Y coordinate is the same as is an east-west road, and each pole sports this same coordinate, hence it's just like a road name sign, but smaller.

想想看，如果您是地圖業者，圖緣的老 ＡＢＣ １２３ 座標如果有辦法到處貼， 讓用您的地圖的遊客一瞄例如電線桿就知道他現在在圖上的哪裡，那不得了。 其實不必貼，台電公司已經幫您貼， 圖緣換用台電座標就達到目的了．．．

多些資料

為了節省時間，出門前我們可以將２度ＴＭ座標先反算成電力座標， 並於地圖上註記， 以避免現場換算（如我叫上河去做的）。 以下利用簡單公式說明：以ＧＰＰＱＱ ＲＳＴＵ﹝ＶＷ﹞ 代替Ｇ７７６７ ＥＤ１２﹝３３﹞， 並以Ｇ大區（西側Ｘ座標為１７００００公尺，南側Ｙ座標為２６５０ ０００公尺）為例可以訂出以下公式

Ｘ座標＝ １７００００＋８００ＰＰ＋１００（Ｒ－１）＋１０Ｔ﹝＋Ｖ﹞米東

Ｙ座標＝２６５００００＋５００ＱＱ＋１００（Ｓ－１）＋１０Ｕ﹝＋Ｗ﹞米北

見如上河臺中縣豐原市附近五萬分之一圖，Ｙ座標２６８２千米北的座標方格網 橫線，經轉換後的電力座標為ＧＸＸ６４ ＸＡＸ０﹝Ｘ０﹞（其中Ｘ為變數， 視你在此東西線之位置而定）， 我們稱此座標線為６４Ａ線，將之標註圖上。同樣， Ｘ座標２２３千米東的座標縱線， 經轉換的電力座標為Ｇ６６ＹＹ ＣＹ０Ｙ﹝０Ｙ﹞（Ｙ為變數），簡稱６６Ｃ， 將之加註圖上。 圖上Ｙ座標２２３０００及Ｘ座標２６８２０００的位置（即泉州杭、 龍鼎山莊附近）若有一電線桿， 其電力座標必為Ｇ６６６４ ＣＡ００﹝００﹞。

Ｘ座標： ２２３０００＝１７００００＋８００＊ＰＰ＋１００＊ （Ｒ－１）＋１０Ｔ﹝＋Ｖ﹞ ﹝其中ＰＰ＝６６，Ｒ＝３（即Ｃ），Ｔ＝０，Ｖ＝０﹞

Ｙ座標： ２６８２０００＝２６５００００＋５００＊ＱＱ＋１００＊ （Ｓ－１）＋１０Ｕ﹝＋Ｗ﹞ ﹝其中ＱＱ＝６４，Ｓ＝１（即Ａ），Ｕ＝０，Ｗ＝０﹞

上面括弧中的Ｖ，Ｗ為一米碼，只顯現在電線趕／箱密集的市區， 其精度可到達一米， （阿Ｑ我說）比單一ＧＰＳ衛星定位儀測出的座標值還準確 （另外，電線密的地方，房子也高，此時ＧＰＳ更難發揮功效了）， 甚至不受地震地理位移的干擾計算出地震前的座標。

前邊忘記噴上台北大區之Ｂ字等等狀況， 到了中部就要特別注意電線箱的水泥基礎， 因為座標常噴那裡，而到南部恐怕只剩下這些箱子， 因為電線桿還是很多掛著非座標系統的牌子， 這種舊型牌子是無法換算２度ＴＭ座標的。

除此之外，平常東西或南北向的農水路雖沒有道路名稱， 我們仍可由地圖座標或沿線電線桿牌上座標為這條農水路取名。 例如沿２６７４１３０米北座標（東西向）農路可以稱之為４８Ｂ３路 ，我們沿著南北向的路找此４８Ｂ３路時， 看到電線桿牌子為ＧＸＸ４８ ＸＢＸ３﹝Ｘ０﹞ （Ｘ為變數）時就知道已經找到路口了。 （另一例：台中縣新社鄉馬力埔） 瞭解電線桿／箱牌子的意義後，若到朋友的新家做客， 只需帶著２度ＴＭ座標地圖， 並請朋友告訴你他家門前的電線桿／箱牌號即可，當然， 也請他一併告訴你附近另一、兩支桿號， 怕萬一一支是連桿帶牌由外地移來，另外忘了帶指北針， 且找不到北極星時， 還可利用二支電線桿的相對位置來定出北方呢！你可以試試， 用這種方式拜訪朋友家可增添不少神秘感喔。

不管是為了電腦選閱圖或林務局、地政事務所， 查地、 查圖， 電力座標經轉換則給了一般民眾辦法提供某地之座標。

Original article 原版: 座標就在你身邊－怎樣利用路邊電線桿及電線箱算出二度ＴＭ座標 ["Your coordinates are right there on the nearest electric pole -- How to use Taipower's pole and box numbers to get your TM-2 degree coordinates"] : 4/1998 台灣地政雜誌 Taiwan land administration magazine #152期 P. 34-36 感謝地政處洪欽雄先生當時打字， 『電力座標』也是他想起來的。

You see, it all came clear one day as I was sitting in my mountain top retreat. I noticed the birds, then the bees, then the numbers on the electric poles.

Enlarged photos are on my "me" page 有放大相片.

仍有一類桿未提， 警察電訊線「警訊」桿屬警察電信所， 無定位價值。

本頁一日應編入維基百科：電力座標或維基教科書。 This page should one day be edited into Wikipedia (already a Chinese page) or Wikibooks. See also Wikipedia:Utility_pole#Coordinates_on_pole_labels

歡迎引用。 版權聲明：ＧＮＵ 通用許可證 Copying welcome. Copyright: GNU General Public License.

Last modified: 2007-11-28 04:06:32 +0800