【文章內(nèi)容簡介】 he Earth’s physical features and the built environment. Geomatics includes disciplines such as :Surveying, Geodesy, Remote Sensing amp。 Photogrammetry, Cartography, Geographic Information Systems, Global Positioning Systems.（測繪學(xué)測量，表示，分析，管理，重獲和顯示空間信息，用來描述地球物理特征和環(huán)境。測繪學(xué)包括的學(xué)科有：測量學(xué)，大地測量學(xué)，遙感和攝影測量學(xué)，制圖學(xué)，GIS，GPS ）[from the Dept. of Sruveying and Spatial Information Science at the Univ. Of Tasmania]（摘自塔斯馬尼亞大學(xué)，測量與空間信息科學(xué)系）Unit 2 Geodetic Surveying and Plane Surveying（大地測量與平面測量）Surveyinghasbeentraditionallydefinedastheartandscienceofdeterminingthepositionof naturalandartificialfeatureson,aboveorbelowtheearth’ssurface。andrepresentingthisinformationinanalogformasacontouredmap,paperplanorchart,orasfiguresinreporttables,orindigitalformasathreedimensionalmathematical model stored in the puter.（測量傳統(tǒng)定義為確定地表、地下和地上的自然與人工地貌特征；并使之按比例測繪成地形圖、平面圖或圖表，或形成報告圖表，或以數(shù)字形式形成三維立體數(shù)學(xué)模型存儲進(jìn)計算機(jī)）As such, the surveyor/geodesist dealt with the physical and mathematical aspect of measurement.（同樣的，測量員/大地測量學(xué)家處理的就是測量出的物理的和數(shù)學(xué)的特征)The accurate determination and monumentation of points on the surface of the Earth is therefore seen as the major task.（因此精確確定并標(biāo)定地表點位便成為測量的主要任務(wù)）Though these surveys are for various purposes, still the basic operations are the samethey involve measurements and putations or, basically, fieldwork and office work.（雖然測量工作有不同目的，基本的操作卻都一樣――他們包括測量和計算，或更基本地稱之為，外業(yè)工作和內(nèi)業(yè)工作）There are many different types of surveys such as land surveys, route surveys, city surveys, construction surveys, hydrographic surveys, etc., but generally speaking, surveying is divided into two major categories: geodetic and plane surveying.（測量分為許多不同的類型，如土地測量，路線測量，城市測量，建筑測量，水道測量等等，但是總的來說，測量分為兩個主要的種類：大地測量和平面測量）Surveys will either take into account the true shape of the Earth（Geodetic surveys） or treat the earth as a flat surface(Plane surveys). （是考慮地球真實形狀的大地測量還是將地球當(dāng)成一個平面的平面測量）Additionally, surveys are conducted for the purpose of positioning features on the ground(Horizontal surveys), determining the elevation or heights of features(Vertical surveys) or a bination of both.（另外，測量還分為確定平面位置的水平測量和確定海拔的高程測量或兩者的綜合。）Geodetic Surveying（大地測量）The type of surveying that takes into account the true shape of the earth is called geodetic surveying. （考慮地球真實形狀的測量工作稱為大地測量）This type of survey is suited for large areas and long lines and is used to find the precise location of basic points needed for establishing control for other surveys. （這種測量適用于大范圍和長距離的測量工作，用來確立基本點的精確位置，用以建立其他測量工作所需的控制網(wǎng)。）In geodetic surveys, the stations are normally long distances apart, and more precise instruments and surveying methods are required for this type of surveying than for plane surveying.（在大地測量中，站點經(jīng)常是互相距離很遠(yuǎn)，那么這種測量就比平面測量需要更精確的儀器和測量方法。）Widely spaced, permanent monuments serve as the basis for puting lengths and distances between relative positions. （廣泛間隔開的永久標(biāo)石就作為計算點位之間距離的基礎(chǔ)）These basic points with permanent monuments are called geodetic control survey points, whichsupport the production of consistent and patible data for surveying and mapping projects.（這種永久標(biāo)石點被稱為大地控制點，為測量和繪圖工作提供可靠和一致的數(shù)據(jù)）In the past,groundbased theodolites, tapes , and electronic devices were the primary geodetic field measurements used. （過去，大地經(jīng)緯儀、卷尺和電子設(shè)備是大地測量的野外工作初時的工具。）Today, the technological expansion of GPS has made it possible to perform extremely accurate geodetic surveys at a fraction of the cost.（現(xiàn)在，技術(shù)的發(fā)展 GPS使大地測量工作花費非常小的代價就能獲得極為精確的結(jié)果成為可能。）A thorough knowledge of the principles of geodesy is an absolute prerequisite for the proper planning and execution of geodetic surveys.（大地測量工作計劃的編制和實施，絕對需要對大地測量學(xué)知識有全面的掌握。）In Geodetic Surveys, the shape of the earth is thought of as a spheroid, although in a technical sense, it is not really a spheroid.（在大地測量中，地球的形狀被看成一個橢球體，雖然在技術(shù)角度來看，它不是真正的橢球?！净蚋浇鼫y量距離并不是沿著直線或平面進(jìn)行，而是在一個曲面上?！? Hence, in the 在大地測量距離的計算中，參考橢球的長軸與短軸所帶來的誤差就顯示出來。）The position of each geodetic station is related to this spheroid.（每個大地站點的位置都與這個橢球有關(guān)）The positions are expressed as latitudes(angles north or south of the Equator) and longitudes(angles east or west of a prime meridian) or as northings and eastings on a rectangular grid.（這個位置是用緯度【與赤道面所成的角】和經(jīng)度【與初子午線所成的角】或用在直角坐標(biāo)系中的北距和東距來表示。）A geodetic survey establishes the A geodetic survey establishes the fundamentals for the determination of the surface and gravity field of a country.（大地測量為建立國家范圍內(nèi)的重力場和確定地表架構(gòu)提供基礎(chǔ)） This is realized by coordinates and gravity values of a sufficiently large number of control points, arranged in geodetic and gravimetric networks.（這將由測定布設(shè)在大地網(wǎng)和重力網(wǎng)中數(shù)量十分巨大的控制點，所得到的坐標(biāo)和重力值來實現(xiàn)） In this fundamental work, curvature and the gravity field of the earth must be considered.（在這項基礎(chǔ)工作中，地球的曲率和重力場都應(yīng)被考慮。）Plane Surveying（平面測量）The type of surveying in which the mean surface of the earth is considered a plane, or in whichthe curvature of the earth can be disregarded without significant error,generally is called plane surveying.（這種類型的測量把地球平均的表面視作平面，或認(rèn)為地球曲率帶來的誤差可以忽略不計，這樣的測量工作稱為平面測量） The term is used to designate survey work in which the distances or areas involved are of limited extent.（這個術(shù)語曾指涉及的距離及范圍非常有限的測量工作） With regard torections, a level line is considered mathematically straight, the direction of theplumb line is considered to be the same at all points within the limits of the survey, and all angles are considered to be plane angles.（由于被當(dāng)成了水平距離和方向，水平線被當(dāng)成直線，在這個有限范圍內(nèi)所有點上的鉛垂線方向被認(rèn)為是相同的，所有的角被認(rèn)為都是平面角。）To make putations in plane surveying, you will use formulas of plane trigonometry, algebra, and analytical geometry. （在平面測量的計算中，你可以使用平面三角、代數(shù)、計算中，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 planesurveying methods, but the accuracy and precision of such results will decrease as the area surveyed increases in size. （小范圍內(nèi)，平面測量方法可以獲得精確的結(jié)果，但是隨著范圍的擴(kuò)大，精度和準(zhǔn)確度將隨之下降）Forexample,thelengthofanarckmlonglyingintheearth’ssurface160