【正文】 ） 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。） 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”。） 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。） 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。） The odometer is a simple device that can be attached to any vehicle and directly registers the number of revolutions of a wheel.（自動計(jì)程儀是一個簡單的裝置，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)。） Here gives a brief summary of relevant techniques and their respective accuracies（ : 這里給出一個簡短的 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。） 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。） The geodetic survey adopts the parameters determined by measurements of the earth, and its own results are available to those who measure the earth. （大地測量采用通過測量地球得到的參數(shù)，而其計(jì)算結(jié)果又可以被測量地球【確定地球參數(shù)】的工作所利用【 available 可利用的】） The plane surveys, in turn, are generally tied to the control points of the geodetic surveys and serve particularly in the development of national 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)。） The ordinary procedure in determining elevations, such as【像這樣、例如】 balancing backsight and foresight distance in differential leveling, automatically takes into account the curvature of the earth and pensates for earth curvature and refraction, and elevations referred to the curved surface of reference are secured without extra effort by the surveyor.（常規(guī)的測高程的程序是，例如，在微差水準(zhǔn)測量【 differential leveling】中平衡前后視距【 使前后視距相等】，地球曲率和大氣折光影響將被自動考慮和低償【 pensate】，不必經(jīng)測量者額外改正【 effort 努力】，至參考曲面的高程就是可靠的了。） At horizontal distances of 1km from the point of tangency, the vertical distances(or elevations) of the plane above the surface represented by mean sea level are .（在離切點(diǎn) 1km 的地方，這個平面高于平均海平面的垂直距離為 ?！浚? We use mean sea level as a datum or, curiously and incorrectly, a datum plane upon which we can reference or describe the heights of features on, above or below the ground. （我們用平均海平面作為一個數(shù)據(jù)，或不常用地和不準(zhǔn)確地，當(dāng)作一個基準(zhǔn)面【 datum plane】，通過它我們可以參考和描述地上、地表、地下的情況。）【 for 引導(dǎo)原因】 Mean sea level is the average level of the ocean surface halfway between the highest and lowest levels recorded. （平均海平面是海水表面高度的記錄值的平均值。） If we allowed the trench to fill with seawater, the surface of the water in the trench would represent he geoid. （如果我們允許這條溝渠注滿海水，溝渠里的水面就代表大地水準(zhǔn)面。【或者說高程是相對于大地水準(zhǔn)面而言的】） The geoid is theoretical only.（大地水準(zhǔn)面只是在理論上存在） It is the natural extension of the mean sea level surface under the landmass. （它是平均海平面在大陸下的自然延伸?！厩懊嬷v多數(shù)測量工作為平面測量，這里就轉(zhuǎn)折的說從事平面測量的人員能進(jìn)行的工作越來越少】） The operation of determining elevation usually is considered a division of plane surveying. （我們通常把高程的測量與平面測量分開來。） To make putations in plane surveying, you will use formulas of plane trigonometry, algebra, and analytical geometry. （在平面測量的計(jì)算中，你可以使用平面三角、代數(shù)、和平面解析幾何的公式） For small areas, precise results may be obtained with plane surveying methods, but the accuracy and precision of such re