【導(dǎo)讀】（Geomatics－測繪或地球空間信息學(xué)，這個(gè)名詞。orGIS-orientedcourses.（這個(gè)術(shù)語作為一個(gè)學(xué)科?；颉皽y量學(xué)”在引入了許多計(jì)算機(jī)科學(xué)和GIS方向的課程后重新命名的。相互之間架起了廣泛的橋梁。activities.（surveyor這個(gè)詞按慣例用來總指（這換成“總稱”較好）。expertise.（更具體的工作如土地測量員、工程測量員和水道測。一般地】被業(yè)內(nèi)人士用來更準(zhǔn)確的描述他們的專門技術(shù)。聯(lián)的活動(dòng)的自然科學(xué)，并使這些領(lǐng)域的未來技術(shù)發(fā)展的結(jié)合。aworldwidebasis.（這個(gè)術(shù)語的采用同時(shí)也在全世界范圍里為行業(yè)里和學(xué)校建

　　

【正文】 onal map series and in the formation of real estate cadastres.（接下來【 in turn】，平面測量，一般依賴于大地測量建立的控制點(diǎn)，在國家地圖系列【國家地圖集】的發(fā)展和在房地產(chǎn)地籍【 real estate cadastre】信息領(lǐng)域提供特別服務(wù)。） Unit 3 DistanceMeasurement（距離測量） One of the fundamentals of surveying is the need to measure distance. （ 測量工作的一項(xiàng)基礎(chǔ) 【 fundamental 基本原則，同時(shí)有基礎(chǔ)的意思】是距離測量） Distances are not necessarily linear, especially if they occur on the spherical earth（ . 距離不一定指的是直 線的，尤其是在地球曲面上的距離） In this subject we will deal with distances in Euclidean space, which we can consider a straight line from one point or feature to another. （這里【 In this subject 翻譯成這里】，我們所涉及的是歐幾里德空間， 我們可以認(rèn)為一條從一點(diǎn)到另一點(diǎn)或一個(gè)特征到另一個(gè)特征的線是直線。） Distance between two points can be horizontal, slope, or vertical. （兩點(diǎn)之間的距離可以是平距、斜距、 或者是垂距。） Horizontal and slope distances can be measured with lots of techniques of measurement depending on the desired quality of the result. （根據(jù)測量結(jié)果的精度【 quality 質(zhì)量】要求不同，平距或斜距有多種測 量方法） If the points are at different elevations, then the distance is the horizontal length between plumb lines at the points. （如果這些點(diǎn)在不同高程上，那么平距指的是過點(diǎn)的垂線【 plumb lines】之間的水平長 度。） Here gives a brief summary of relevant techniques and their respective accuracies（ : 這里給出一個(gè)簡短的 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（步測和自動(dòng)計(jì)程儀） Pacing is a very useful form of measurement though it is not precise, especially when surveyors are looking for survey marks in the field.（雖然不精確，但步測是一個(gè)非常有用的測量方法【 form of measurement】，尤其是測量者在野外尋找測量標(biāo)志時(shí)。） Pacing can be performed at an accuracy level of 1/100~1/500 when performed on horizontal land, while the accuracy of pacing can’ t be relied upon when pacing up or down steep hills.（當(dāng)在水平場地進(jìn)行時(shí)， 步測可以達(dá)到 1/100 到 1/500 的相對精度，而當(dāng)?shù)孛嫫鸱^大時(shí)，這樣的精度就不能保證了。） The odometer is a simple device that can be attached to any vehicle and directly registers the number of revolutions of a wheel.（自動(dòng)計(jì)程儀是一個(gè)簡單的裝置，可以附屬于【 be attached to 附屬于】車輛之 上并直接記錄【 register 記錄 v.】輪子的旋轉(zhuǎn)周數(shù)。） With the circumference of the wheel known, the relation between revolutions and distance is fixed. （由 于知道了輪子的周長【 circumference of the wheel 輪周】，轉(zhuǎn)數(shù)【 revolution 這里有轉(zhuǎn)數(shù)的意思】和 距離之間的關(guān)系就確定下來【 fix 確定】。） Ordinary Taping and Precise Taping（普通尺距測量和精密尺距測量） Taping is a very mon technique for measuring horizontal distance between two points.（尺距測量是 測量兩點(diǎn)之間平距的非常普遍的方法。） Ordinary taping refers to the very mon tapes that we can buy them in stores, such as the plastic tapes or poly tapes.（普通尺距測量使用【 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 我們想測量 A 點(diǎn)和 B 點(diǎn)之間的平距，我們可以這樣來做：） 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， 我們在尺上將得到不同的的讀數(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.（如果距離比尺長要長，那么【 then】我們可 以將其分成幾段【 segment】，把每段長加起來獲得總長。） 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 （視距測量和視距儀） Tacheometry is an optical solution to the measurement of distance.（視距測量是一個(gè)光學(xué)【 optical】測 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】希臘語的 Tas，意思是“迅速的”，和 metrot【同樣是希臘語】， 意思是“方法”。） Tacheometry involves the measurement of a related distance parameter【參數(shù)】 either by means of a fixedangle intercept.（視距測量包括一個(gè)相關(guān)距離參數(shù)的測量和依靠定角截距的測量【 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)語態(tài)，翻譯為將； direct at 對準(zhǔn)??】對準(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【 ？】， D=Ks + C） Usually the no