【文章內(nèi)容簡(jiǎn)介】 以數(shù)字形式 形成三維立體數(shù)學(xué)模型存儲(chǔ)進(jìn)計(jì)算機(jī)。 ） As such, the surveyor/geodesist dealt with the physical and mathematical aspect of measurement. （同樣的，測(cè)量員/大地測(cè)量學(xué)家處理的就是測(cè)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(diǎn)位便 成為測(cè)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(cè)量工作有不同目的，基本的操作卻都一樣――他們包括測(cè)量和計(jì)算， 或更基本地稱(chēng)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(cè) 量分為許多不同的類(lèi)型，如土地測(cè)量，路線測(cè)量，城市測(cè)量，建筑測(cè)量，水道測(cè)量等等，但 是總的來(lái)說(shuō)，測(cè)量分為兩個(gè)主要的種類(lèi)：大地測(cè)量和平面測(cè)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(shí)形狀的大地 測(cè)量還是將地球當(dāng)成一個(gè)平面的平面測(cè)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(cè)量還分為確定平面位 置的水平測(cè)量和確定海拔的高程測(cè)量或兩者的綜合。 ） Geodetic Surveying（大地測(cè)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(shí)形狀的測(cè)量工作稱(chēng)為大地測(cè)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(cè)量適用于大范圍和長(zhǎng)距離的測(cè)量工作，用來(lái)確立基本點(diǎn)的精確位置，用 以建立其他測(cè)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(cè)量中，站點(diǎn)經(jīng)常是互相距離很遠(yuǎn)，那么這種測(cè)量就比平面測(cè)量 需要更精確的儀器和測(cè)量方法。 ） Widely spaced, permanent monuments serve as the basis for puting lengths and distances between relative positions. （廣泛間隔開(kāi)的永久標(biāo)石就作為計(jì)算點(diǎn)位之間距 離的基礎(chǔ)） These basic points with permanent monuments are called geodetic control survey points, which support the production of consistent and patible data for surveying and mapping projects.（這種永久標(biāo)石點(diǎn)被稱(chēng)為大地控制點(diǎn)，為測(cè)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(guò)去，大地經(jīng)緯儀 、卷尺和電子設(shè)備是大地測(cè)量的野外工作初時(shí)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(cè)量工作花費(fèi)非常小的代價(jià)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(cè)量工作計(jì)劃的編制和實(shí)施， ，絕對(duì)需要對(duì)大地測(cè)量學(xué)知識(shí)有全面的掌握。 thorough knowledge of the principles 【A of geodesy is an absolute prerequisite 一個(gè)徹底的知識(shí)――大地測(cè)量學(xué)的原理的，是 絕對(duì)需要的。） 】 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(cè)量中，地球的形狀被 看成一個(gè)橢球體，雖然在技術(shù)角度來(lái)看，它不是真正的橢球。 ） Therefore, distances measured on or near the surface of the earth are not along straight lines or planes, but on a curved surface.（因此，在地球表面上或附近測(cè)量 距離并不是沿著直線或平面進(jìn)行，而是在一個(gè)曲面上。) Hence, in the putation of distances in geodetic surveys, allowances are made for the earth’s minor and major diameters from which a spheroid of reference is developed. （因此，在大地測(cè)量距離的計(jì)算中，參考橢球的長(zhǎng)軸與短軸所帶來(lái)的誤差就顯示出來(lái)。 ） The position of each geodetic station is related to this spheroid. （每個(gè)大地站 點(diǎn)的位置都與這個(gè)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(gè)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(lái)表示。 ） A geodetic survey establishes the fundamentals for the determination of the surface and gravity field of a country. （大地測(cè)量為建立國(guó)家范圍內(nèi)的重力場(chǎng)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(cè)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(diǎn)，所得到的坐標(biāo)和重力值來(lái)實(shí)現(xiàn)） In this fundamental work, curvature and the gravity field of the earth must be considered.（在這項(xiàng)基礎(chǔ)工作中，地球的曲率和重力場(chǎng)都應(yīng)被考慮。 ） Plane Surveying（平面測(cè)量）The type of surveying in which the mean surface of the earth is considered a plane, or in which the curvature of the earth can be disregarded without significant error, generally is called plane surveying.（這種類(lèi)型的測(cè)量把地球平均的表面視作平面，或 認(rèn)為地球曲率帶來(lái)的誤差可以忽略不計(jì)，這樣的測(cè)量工作稱(chēng)為平面測(cè)量[significant 重大 的，不翻譯也行]） The term is used to designate survey work in which the distances or areas involved are of limited extent.（這個(gè)術(shù)語(yǔ)曾指涉及的距離及范圍非常有限的測(cè)量工作） With regard to horizontal distances and directions, a level line is considered mathematically straight, the direction of the plumb 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(gè)有限范圍內(nèi)所有點(diǎn)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(cè)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 results will decrease as the area surveyed increases in size. （小范圍內(nèi)，平面測(cè)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） For example, the length of an arc km long lying in the earth’s surface is only 7mm greater than the subtended chord and, further, the difference between the sum of the angles in a plane triangle and the sum of those in a spherical triangle is 2 only second for a triangle at the earth’s surface having an area of 100km . （例如， 地球表面一條 長(zhǎng)的弧只比其所對(duì)的 弦長(zhǎng) 7mm，在一個(gè)面積為 100 平方公里的平面三角形中的內(nèi)角和與對(duì)應(yīng)球面三角 形中的內(nèi)角和之差只有 秒） It will be appreciated that the curvature of the earth must be taken into consideration only in precise surveys of large areas.（只有在大面積的精密測(cè)量工 作中地球曲率才必需被考慮） 。 A great number of surveys are of the plane surveying type.（多數(shù)的測(cè)量工作都是屬