【正文】 ef summary of relevant techniques and their respective accuracies: （這里給出一個(gè)簡(jiǎn)短的相關(guān)【relevant 相關(guān)的】技術(shù)的摘要【summary 摘要】和它們各自的【respective 各自的】精度）Pacing and Odometer（步測(cè)和自動(dòng)計(jì)程儀）Pacing is a very useful form of measurement though it is not precise, especially when surveyors arelooking for survey marks in the field.（雖然不精確，但步測(cè)是一個(gè)非常有用的測(cè)量方法【form ofmeasurement】，尤其是測(cè)量者在野外尋找測(cè)量標(biāo)志時(shí)。）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”?！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。）At a given point there is only one vertical line.（在給定的一個(gè)點(diǎn)上只有一條垂線。.（豎直角位于【lie 位于】0～90 度之間）Zenith is the term describing points on a celestial sphere that is a sphere of infinitely large radiuswith its center at the center of the earth.（天頂方向是一個(gè)術(shù)語(yǔ)，用來(lái)描述在天球【celestial sphere天球】上的點(diǎn)，天球是一個(gè)半徑無(wú)限【infinitely 無(wú)限地】大的球，其中心在地球中心。 that is, it is measured or designed to theright or to the left, or it is considered clockwise or counterclockwise.（在測(cè)的水平角有方向【direction、sense 這里都是方向的意思】，就是說(shuō)【that is】它是向左測(cè)還是向右測(cè)，或者是說(shuō)，順時(shí)針測(cè)還是逆時(shí)針測(cè)）In the above figure, the angle at A from B to C is clockwise and the angle from C to B is counterclockwise.（如上圖所示，在 A 點(diǎn)由 B 到 C 就是順時(shí)針角，而從 C 到 B 就是逆時(shí)針角）With the theodolite set up, centered, and leveled over at station A, then a simple horizontal anglemeasurement between surveying point B, A and C would be taken as follows:（經(jīng)緯儀在 A 點(diǎn)安置、對(duì)中、整平后，在 B、A 和 C 測(cè)量點(diǎn)間的簡(jiǎn)單的水平角測(cè)量可以按下列步驟進(jìn)行：）⑴Commencing on, say, “face left”, the target set at survey point B is carefully bisected and thereading on horizontal scale is 25176。 to 360176。 and 177。 (3)Infraredsystems with range up to 3 km, limited to line of sight and limited by rain, fog, other airborne particles.（EDM 使用三種不同波長(zhǎng)的波段：(1)微波系統(tǒng)【波段】，其測(cè)距范圍達(dá) 150km，波長(zhǎng) 3cm，不受限于視線范圍，也不受可見(jiàn)度的影響；(2)可見(jiàn)光波段，有效范圍 5km（小型儀器），可見(jiàn)光、激光，其距離受可見(jiàn)度的影響會(huì)降低；(3)紅外線【Infrared】波段，測(cè)程 3km，受限于視線范圍，并且受限于空氣中的微粒影響）Although there is a wide variety of EDM instruments available with different wavelengths, there arebasically only two methods of measurement employed which may divide the instruments into twoclassification as electrooptical (light waves) and microwaves (radio waves) instruments.（盡管不同的EDM 用到不同的波長(zhǎng)，基本上只有兩種測(cè)量方法在使用，可以將其【即 EDM】分為光電測(cè)距儀和微波測(cè)距儀）These two basic methods are namely the pulse method and more popular phase different method. （這兩種基本方法即【namely 即】脈沖【pulse】法和更流行的相位【phase different 相位的不同】法）They function by sending light waves or microwaves along the path to be measured and measuring thetime differences between transmitted and received signals, or in measuring the phase differences betweentransmitted and received signals in returning the reflecting light wave to source. （沿著要測(cè)的路徑發(fā)射光波或微波，并測(cè)出發(fā)射和收到反射信號(hào)之間的時(shí)間間隔，或者是測(cè)出發(fā)射和接受反射信號(hào)之間的相差【phase differences】，它們通過(guò)這種方法來(lái)運(yùn)行【function v.】）Modern EDM instruments are fully automatic to such an extent that, after the instruments, set up on onestation, emits a modulated light beam to a passive reflector set up on the other end of the line to bemeasured.（現(xiàn)代的 EDM 全自動(dòng)化到這樣的程度【to such an extent that 到這樣的程度】，在一個(gè)站點(diǎn)安置，需測(cè)距離線的另一處安置有反射棱鏡，發(fā)射一束已調(diào)制【modulated 已調(diào)制的】的光束到棱鏡上）The operator need only depress a button, and the slope distance is automatically displayed. （操作者僅僅需要按一個(gè)鍵，斜距就自動(dòng)顯示出來(lái)。）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 detailsurveys, 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 determiningdistances.（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 determinedistances. （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 ofGeodimeter 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。）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 andhave 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 distancemeasurement. （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 thehorizontal 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 plumbline 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 willfind the changes of reading in the tape.（