電力座標與2度TM座標的關係

Taiwan Power Company Grid and TM-2 Grid Relationship

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積丹尼著 by Dan Jacobson

[Photo: Author caught red-handed copying coordinate (B)6737 AE90]

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., Taipei.

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市東勢區, 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.

加印個位數字的 1*1 meter plate example.

[Photo: An old style pole label band]

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.]

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

In 2009, 在台中市我觀察到如 I observed in Taichung city e.g.,

  G6349GE46 桿另掛 pole also had
25G6349GE46 路燈編號鐵環 street lamp number steel band attached.

當處逐桿燈號均前綴25。 All the poles in the area had the same 25 prefix on the lamp number.

地圖集 Atlases

已套電力座標 With TaiPower grids

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.


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

見如上河臺中市豐原區附近五萬分之一圖,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:台中市新社區馬力埔) 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。


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

積丹尼 Dan Jacobson

Last modified: 2016-01-02 13:02:15 +0800