Taiwan Power Company grid

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台灣電力公司座標 (閱本頁於中文框)

台灣電力公司座標(電力座標)值得學習,其遍及全台而可利用定位,作「窮人的 GPS」…

The Taiwan Power Company grid is significant in that it presents a freely available "poorman's GPS" on every power pole and switch box in Taiwan, and could be readily incorporated into projects like Openstreetmap as a supplemental grid. Here we present how to convert the Taiwan Power Company grid into Taiwan datums thus ultimately connecting it to worldwide coordinate systems.

Unlike some proprietary systems the algorithm is open and you can memorize it and use pencil and paper to do your conversions. No need to wait for the electric company's office hours to ask for help.

一般桿牌 A typical pole with grid plate "G8152 FC56"

電力座標與TWD67 2度TM座標的換算公式 Taiwan Power Company grid and TM-2 relationship

總攬 Overview

Figure 1. G8150 HD78

圖一 Figure 1: 視本牌 Looking at the number plate with coordinates G8150 HD78 (呼之 call this GPPQQRSTU[VW]).

G  is a 80 × 50 km rectangle 如圖二 see figure 2.
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

設備密集都市中也有 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

我們首先看看台電公司電線杆的牌子,該牌子的下兩行就是座標,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,這是台灣地圖常見座標系統之一,勿混淆。 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. Again, the last two lines of that plate, G8150 HD78, are the coordinates. We can convert them to TM-2 coordinates, version TWD67, one of the common systems found on Taiwan maps, don't confuse them. Let's take a look at the meaning of each of those numbers.

A-Z 區 areas

Figure 2. Taiwan: TM-2 TWD67 grid with TaiPower 80×50km area letters

圖二: 以東西寬八十公里,南北長五十公里為範圍,將台灣劃分區域並以英文字母代表所在位置大區域,如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, Taizhong County, Dongshi Township, which lies in the G sector.

他區 Other areas:


Figure 3. Location of G8150 inside G sector

圖三: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座標為170000+81*800=234800公尺,南側之Y座標為2650000+50*500=2675000公尺,這就是電力座標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.


Figure 4. Breakdown of area 8150 from AA to HE


Figure 4. 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, TaiPower grid HD 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...


Figure 5. Position of 78 inside G8150 HD


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.

總合 Summing up

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。

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.


在都市地區,因電線杆∕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,比單 一GPS衛星定位儀測出的座標值還準確(另外,電杆∕箱密的地方,房子也高,此時GPS更難 發揮功效了)。

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…

400x250 圖 maps

田野中偶而會發現些如: Occasionally in the field one may run across coordinates like:

多餘之一字即 400 × 250 米圖: These extra letters correspond to 400 × 250 meter maps,

| A  | B  |
| C  | D  |
0   400  800

該多餘之一字完全能由接著之字計算: And their extra letter is merely a function of the following letters:

while (<>) {
    unless (/[A-H][A-E]\d\d/) { print "Invalid: $_"; next; }
    my $x = 0 + /[E-H][A-E]/;
    my $y = 0 + ( /[A-H][AB]/ || /[A-H]C[0-9][0-4]/ );
    my $c = chr( ord('A') + oct("0b$y$x") );
    s/ /$c /;

街景例 Street View Examples

台灣 Taiwan

$ echo G8152 FC56 | taipowergrid
#1 G8152 FC56
235350 2676260
$ echo 235350 2676260 | cs2cs -f %.7f +proj=tmerc +lon_0=121 +k=0.9999 +x_0=$((250000-828)) +y_0=207
120.8639458	24.1898278 0.0000000

近其 Google 街景網址中之經緯地! Close to the coordinates in its Google Street View URL!

今(2017年)亦能簡, Now (2017) we can also do just:

$ echo G8152 FC56 | taipowergrid | proj -I +init=epsg:3828 | cs2cs -f %.6f +init=epsg:4236 +to +init=epsg:3824
#1 G8152 FC56
120.8639476	24.1898534 20.6759462

近 Close! (Perl:)

use Math::Trig qw(great_circle_distance deg2rad);
sub NESW { deg2rad( $_[0] ), deg2rad( 90 - $_[1] ) }
my @L = NESW( 120.8639476, 24.1898534 );
my @T = NESW( 120.8639458, 24.1898278 );
print great_circle_distance( @L, @T, 6378137 );

僅差三米。shows only a three meter difference. 另例,明確離 121.0000 而入 WGS84. Another example, clearly showing we have gone away from 121.0000 and entered WGS84.

$ echo B0000 AA00 | taipowergrid | proj -I +init=epsg:3828 | cs2cs -f %.6f +init=epsg:4236 +to +init=epsg:3824
#1 B0000 AA00
121.008200	24.855717 20.319216

反之 Reversing

$ echo 120.8639458 24.1898278 | cs2cs -I -f %.0f +proj=tmerc +lon_0=121 +k=0.9999 +x_0=$((250000-828)) +y_0=207
235350	2676260 0
$ echo 235350 2676260 | taipowergrid
#1 235350 2676260
G8152 FC5600
<<EOF cs2cs -I +init=epsg:4236 +to +init=epsg:3824 | \
proj -f %.0f +init=epsg:3828 | perl -awle 'print "@F[0,1]"' | taipowergrid
120.863948 24.189853
121 24
#1 235350 2676260
G8152 FC5600
#2 249171 2655228
G9810 HC7218

大概都能再簡化 All this could probably be further simplified.

另見 See also #新桿設牌 Calculating new pole labels.

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.

|  X   |
|      |
|  Y   |
|      |
275000 355000

例 Examples

$ echo  Y4087 DD1053 | taipowergrid
#1 Y4087 DD1053
307315 2607803 119
$ echo 307315 2607803 | cs2cs -f %.7f +proj=tmerc +lon_0=119 +k=0.9999 +x_0=$((250000-828)) +y_0=207
119.5695971	23.5706975 0.0000000

的確近似於其 Google 街景網址中之經緯地! Indeed close to the coordinates in its Google Street View URL!

金門 Jinmen

金門用 Jinmen uses EPSG 3829 但 but +zone=50 (+lon_0=117).

金門有兩個同名為 Z 大區。因金門地小,兩 Z 區不衝突。 Jinmen has two sectors both named "Z", which don't conflict as Jinmen is small.

|  Z   |  Z   |
|      |      |
10000 90000 170000

例 Examples

  1. 參數由 2015 年 12 月詢問台電包商。 The parameters come from 2015/12 conversations with Taipower's contractors. 係他們發現較適用之參數, 絕非任何原始定義之意! They are just ones they discovered get the conversion done pretty well. They are in no way any kind of original official definition!
    $ echo Z0054 EC0222 | taipowergrid
    $ echo 90402 2703022 | cs2cs -f %.7f +proj=tmerc +lon_0=117 +ellps=intl +x_0=-42160 +y_0=-205 +k=0.9996 +towgs84=-637,-549,-203 +to +proj=longlat +ellps=WGS84 +towgs84=0,0,0
    118.3157370 24.4349832
  2. Z1856 FC34

烏坵 Wuqiu

未知 Unknown.

馬祖 Mazu

|  S   |
|      |
10000 90000

轉換則與 #金門 Jinmen 略異 The conversion is a little different than Jinmen:

cs2cs +proj=tmerc +lon_0=117 +ellps=intl +x_0=-279825 +y_0=20830 +k=0.9996 +towgs84=-637,-549,-203 +to +proj=longlat +ellps=WGS84 +towgs84=0,0,0

例 Examples

新桿設牌 Calculating new pole labels

假如於 At 26.1653413,119.9589775 立新桿欲製牌, let's say we want to make a label for a new pole,

$ echo 119.9589775 26.1653413 | cs2cs -I +proj=tmerc +lon_0=117 +ellps=intl +x_0=-279825 +y_0=20830 +k=0.9996 +towgs84=-637,-549,-203 +to +proj=longlat +ellps=WGS84 +towgs84=0,0,0

15149.56	2918400.53 -2.31

$ echo 15149 2918400 | taipowergrid

#1 15149 2918400
S0648 DE4090

還好近上列 S0648 DE0185 (經緯由其網址取得), 扣掉 Google 街景車距離等誤差。 Well, at least rather near the above S0648 DE0185 (where we got the coordinates, from the URL,) including the distance to the Google Street View car... ?

反正至少有助於由 URL 猜/重建模糊 Google 街景 100m X 100m 字母… Well at least it might help us guess / reconstruct the 100m X 100m letters of blurry Google Street View photos, via the URL.

提醒 Notices

Grid numbers might be on front or cement base of switch boxes.


All of the switch boxes we've seen have grid numbers, but sometimes you have to look at the cement foundation, as well as the front. The poles on the other hand vary. Some districts only have older poles whose labels lack coordinates.

警告 Warnings

Taiwan datums#混淆 TWD67, TWD97 易耽誤救援 confusion can delay rescues: 台電電力座標採TWD67,非TWD97! Taiwan Power Company grid uses TWD67, not TWD97!

台電電力座標並非精確的座標系統, 原始用途為台電公司各項電力設施的財產編碼系統, 偶有偏離TWD67二度分帶座標數百公尺的案例出現, 此時請以GPS實測座標為準. 亦應參考周圍兩三桿免遇舊桿移新位仍掛舊牌之誤讀. 通報位置時也儘可能告知附近參考地標及接近路線.

Taiwan Power Company grid is not an exact system. It was intended for internal company property management. Sometimes it might be in error several hundred meters -- so then use GPS. Also beware of reused poles still bearing the labels from their former positions. Thus one should check neighboring pole labels for consistency. In any case when using it to report positions, also include names of neighboring roads, etc.

由台電內部看座標 View from inside TaiPower


台電電力座標為1978年由美國 Commonwealth International Inc(康瑪斯工程顧問公司)為台電公司制定一套由TWD67對應的座標系統, 總共為11個字元, p43至p45完整說明台電圖資系統.(論文:天然災害停電搶修指派作業管理系統之開發) (部份源自本 Osgeo 頁.)


台電座標正式名稱是"台電圖號座標"因為前五碼就是1/1200的藍曬圖圖號, 在饋線自動化電腦系統正式名稱"台電電力座標"。


台電座標是TM-2(TWD67), 市面上GPS or 導航軟體是WGS84(極近TWD97), 所以過程是: 台電座標->TWD67->WGS84(TWD97),非常準確, 誤差在10M以內, 因為台電給的通常只到10M, Ex:G3962BC34, 除非在10M內有其他設備才會定到1M內, Ex:G3962BC3437 (台中區處關連二次變電所)。


先有紙本設計規劃(藍曬圖)圖號座標, 再到現場施工, 但因現場環境問題有時會移位(如民眾抗爭), 完工後又未回饋紙本就錯漏, 圖資電腦化後照紙本抄未勘誤。

通常標錯只有一個原因, 給民間包商做牌子做錯啦。 通常地上亭置噴漆的比較不會出錯, 電線桿金屬銘牌較會, 卻亦深少。

在撰寫程式初期我們發現電力座標轉TWD67後有些誤差, 但隨著台電人員的重視修正近幾年的誤差愈來越小。

台電巡修搶救人員由內部藍曬圖找出電線桿有"桿號", 人孔地下開關有"人孔號", 建物地下開關有"建物名", 以上三點在電腦統稱"桿號", 但在台電的圖或電腦上是都桿號及電力座標兩者並存, 電力座標只在"設計規劃", "施工測試"時用, 因為太長無線電傳呼時不好用。

在台電饋線調度中心(FDCC)及巡修股(或課)管理對外民眾配電系統, 就是您打 "1911" 台電接電話的單位, 在圖資未電腦化(OMS 或其他)及饋自化(DAS)是採用1/1200讀的紙本圖上面只有電線桿有"桿號" EX: 關連高幹51, 人孔地下開關有"人孔號" EX: XX路第YY孔, 建物地下開關有"建物名" EX: 台雞店南顆三廠, 為方便一律統稱"桿號"

圖資電腦化(OMS or other)及饋自化(DAS)定義資料結構桿號不夠嚴謹, 所以以電力座標定義, 資料結構嚴謹又可找出實施位置在 "設計規劃", "施工測試"時用電力座標, 但電腦化後調度(值班)人員在指揮調度現場搶修人車以無線電呼叫時電力座標反成累贅(ABCD1234很難念易搞混, 台電未用軍事通信讀音 (A: alpha, B: Bravo, C: Charlie, 么: 1, 兩: 2…), 用桿號反而方便。

現場設備只有電桿有桿號(銘牌), 地下亭置建物內設備只有電力座標(噴漆或銘牌), 但在台電的圖或電腦上都是桿號及電力座標兩者並存。



參閱 See Also

外部連結 External links