【正文】 buy them in stores, such as the plastic tapes or poly tapes. （普通尺距測(cè)量使用【refers to 引用】的是我們可以在商店里買到的非常普遍的的尺子，例如塑膠尺或滌綸尺。）Such tapes have low precision in distance measurements with about 1/3000~1/5000.（這種尺的精度低，測(cè)距精度只有 1/3000 到 1/5000）The precise taping refers to the steel tapes and which are much more expensive than the plastic tape and have higher precision of 1/10000~1/30000.（精密尺距測(cè)量使用的是比塑膠尺貴的多的鋼尺，并具有更高的精度――1/10000 到 1/30000）Invar tapes are posed 35% nickel and 65% steel.（因瓦尺是由 35％的鎳和 65％的鋼組成）This alloy has a very low coefficient of thermal expansion, making the tapes useful in precise distance measurement. （這種合金具有非常低的熱膨脹【thermal expansion】系數(shù)【coefficient】，使得這種尺利于精密距離測(cè)量）Many tapes are now graduated with foot units on one side and metric units on the reverse side. （現(xiàn)在許多尺上都在正面標(biāo)刻【graduate 標(biāo)刻、刻】了英尺計(jì)量單位，而在反面標(biāo)刻了米制計(jì)量單位）Metric units are in meters, centimeter and minimeter with the total length of 20 m, 30 m, 50 m and 100 m.（米制計(jì)量單位是米，厘米和毫米，尺的總長(zhǎng)為 20m、30m、50m 或 100m）If we want to measure the horizontal distance between the two points A and B, we can do like this:（如果我們想測(cè)量 A 點(diǎn)和 B 點(diǎn)之間的平距，我們可以這樣來(lái)做：）With zero of the tape to the higher point B and tape going along the point A, we can measure the horizontal distance by using the plumb bob with pump line entering to the point A.（將尺的 0 刻度對(duì)準(zhǔn)較高點(diǎn) B 點(diǎn)，尺沿向 A 點(diǎn)，我們可以利用在 A 點(diǎn)的鉛垂【plumb bob】垂線【pump line 應(yīng)為 plumb line 垂線】測(cè)出平距）To judge the exact horizontal line, we should move the tape up and down along the pump line and we will find the changes of reading in the tape.（為了確定準(zhǔn)確的水平線，我們應(yīng)沿垂線方向上下移動(dòng)尺子，我們?cè)诔呱蠈⒌玫讲煌牡淖x數(shù)【changes of reading 讀數(shù)的變化】）The shortest reading of the tape is the horizontal distance.（尺子最小的讀數(shù)就是平距）If the distance is longer than the length of tape, then we can divide the long distance into several segments and get the total distance by plus each segment together.（如果距離比尺長(zhǎng)要長(zhǎng)，那么【then】我們可以將其分成幾段【segment】，把每段長(zhǎng)加起來(lái)獲得總長(zhǎng)。）Since different tapes have different starts of zero of the tapes, it is very important to judge where the zero of the tape begins.（由于不同的尺有不同的 0 刻度，判斷尺的 0 刻度在哪兒十分重要。）Tacheometry and Stadia （視距測(cè)量和視距儀）Tacheometry is an optical solution to the measurement of distance.（視距測(cè)量是一個(gè)光學(xué)【optical】測(cè)距方法）The word is derived from the Greek Tas, meaning “swift”, and metrot, meaning “a measure”.（這個(gè)詞源自于【is derived from 源自于】希臘語(yǔ)的 Tas，意思是“迅速的”，和 metrot【同樣是希臘語(yǔ)】，意思是“方法”。）Tacheometry involves the measurement of a related distance parameter【參數(shù)】 either by means of a fixedangle intercept.（視距測(cè)量包括一個(gè)相關(guān)距離參數(shù)的測(cè)量和依靠定角截距的測(cè)量【by means of依靠】【either 表示并列】）Theodolite tacheometry is an example of stadia system. （經(jīng)緯儀視距測(cè)量就是視距儀器的一個(gè)例子）The theodolite is directed at the level staff where the staff is held vertically and the line of sight of the telescope is horizontal.（將經(jīng)緯儀【is directed at 被動(dòng)語(yǔ)態(tài)，翻譯為將；direct at 對(duì)準(zhǔn)……】對(duì)準(zhǔn)水準(zhǔn)尺【level staff】，水準(zhǔn)尺豎直，望遠(yuǎn)鏡的視線【可以翻譯為視準(zhǔn)軸】水平。）By reading the top and bottom stadia hairs on the telescope view and then the horizontal distance from center of instrument to rod can be obtained by multiplying the stadia interval factor K by the stadia interval and plus the distance C which is from the center of instrument to principal focus, . D=Ks + C.（通過(guò)望遠(yuǎn)鏡視野【view】里的上下視距絲讀數(shù)，從儀器到尺的平距可以用視距常數(shù)【stadia interval factor】K 乘視距間隔【stadia interval】加上從儀器中心到主焦點(diǎn)【principal focus】的距離 C 得到。也就是【.=id est】，D=Ks + C）Usually the nominal stadia interval factor K equals 100 which is a constant for a particular instrument as long as conditions remain unchanged, but it may be determined by observation in practice.（通常，名義上的視距常數(shù)K等于100，只要【as long as】條件保持不變，它就是個(gè)特別裝置的【particular instrument指代視距裝置】常數(shù)【constant 常數(shù)】但在實(shí)踐中可以通過(guò)觀測(cè)確定）The value of C is determined by the manufacturer and stated on the inside of the instrument box.（C 值由廠商決定并固定在儀器之內(nèi)）For externalfocusing telescopes, under ordinary condition, C may be considered as 1 ft without error of consequence.（對(duì)于外調(diào)焦望遠(yuǎn)鏡，通常情況下，C 被認(rèn)為是 1 英尺而不會(huì)給結(jié)果帶來(lái)錯(cuò)誤。）Internalfocusing telescopes are so constructed that C is 0 or nearly so。 this is an advantage of internalfocus telescopes for stadia work.（內(nèi)調(diào)焦望遠(yuǎn)鏡因此被發(fā)明【construct 建立、創(chuàng)立】，C 為或近似為 0；這是內(nèi)調(diào)焦望遠(yuǎn)鏡在視距測(cè)量中的一個(gè)優(yōu)點(diǎn)。）Most instruments now used for stadia are equipped with internalfocusing telescopes.（現(xiàn)在大多數(shù)視距儀器都使用內(nèi)調(diào)焦望遠(yuǎn)鏡）Applications of tacheometry include traversing and leveling for the topographic surveys, location of detail surveys, leveling and field pletion surveys for the topographic mapping, and hydrographic mapping.（視距測(cè)量的應(yīng)用包括地形測(cè)量【topographic survey】中的導(dǎo)線測(cè)量【traversing】和水準(zhǔn)測(cè)量【leveling】工作，細(xì)部測(cè)量【detail survey】中的定位，繪制地形圖工作中的水準(zhǔn)測(cè)量和野外完全化測(cè)量，以及水道測(cè)圖）The relative precision is 1:1000 to 1:5000.（其相對(duì)精度為 1:1000 到 1:5000）Stadia is a form of tacheometry that uses a telescopic crosshair configuration to assist in determining distances.（視距儀是視距測(cè)量的一種形式，利用望遠(yuǎn)鏡的十字絲結(jié)構(gòu)幫助測(cè)距）A series of rod readings is taken with a theodolite and the resultant intervals are used to determine distances. （一系列的標(biāo)尺讀數(shù)由經(jīng)緯儀測(cè)出，并且籍此而得到視距間隔，用來(lái)確定距離【resultant由此產(chǎn)生的】）Electronic Distance Measurement(EDM) （電子測(cè)距儀）The Electronic Distance Measurement(EDM) was first introduced in 1950s by the founders of Geodimeter Inc.（電子測(cè)距儀的概念是由 Geodimeter【“光電測(cè)距儀”――商標(biāo)名】公司的創(chuàng)始人在20 世紀(jì) 50 年代引入的。）The advent of EDM instrument has pletely revolutionized all surveying procedures, resulting in a change of emphasis and techniques.（EDM 測(cè)量手段的出現(xiàn)【advent】是對(duì)所有測(cè)量手段的完全的革命【revolutionized 革命化的】，導(dǎo)致【result in】了一場(chǎng)技術(shù)革命【change】和側(cè)重點(diǎn)的改變?！緀mphasis側(cè)重點(diǎn)】）Distance can now be measured easily, quickly and with great accuracy, regardless of terrain conditions.（現(xiàn)在距離可以被很容易、快速和精確的測(cè)量，而又不受地形【terrain】影響。）EDM instruments refer to the distance measurement equipments using light and radio waves. （EDM 是利用光波和無(wú)線電波測(cè)距的設(shè)備【refer to 譯為“是”】）Both light waves and radio waves are electromagnetic.（光波和無(wú)線電波都是電磁波【electromagnetic電磁的】）They have identical velocities in a vacuum (or space) to 299,177。（它們?cè)谡婵罩卸加幸粯拥乃俣?299,177。）These velocities, which are affected by the air’s density, are reduced and need to be recalculated in the atmosphere. （它們的速度，由于會(huì)收到空氣密度的影響而降低，在大氣中需要重新計(jì)算【recalculate】）The basic principle of EDM instruments is that distance equals time multiplied by velocity.（EDM 的基本原理是距離等于時(shí)間乘速度）Thus if the velocity of a radio or light wave and time requir