The operation（工作）of determining elevation is usually considered as a division（一部分）of plane surveying. Elevations are referred to（与..有关）a spheroidal surface, a tangent at any point in the surface being normal to（垂直于）the plumb line at that point. The curved surface of reference, usually mean sea level（平均海平面）, is called a “datum” or curiously and incorrectly, a “datum plane”. The procedure ordinarily used in determining elevations automatically takes into account the curvature（曲率）of the earth, and elevation referred to the curved surface of reference are secured（获得）without extra effort on the part of the surveyor. In this procedure, the curvature of the earth’s surface can not be neglected even for very rough（粗略的）values of elevations.
确定标高的工作通常被认为是平面测量的一部分。标高和椭球体表面有关，该表面上任意一点的切线垂直于该点的铅垂线。通常是平均海平面的参考曲面被称为“基准面”，或奇怪地、不恰当地称为“基准平面”。通常用来确定标高的方法自动考虑了地球的曲率，而关于参考曲面的标高，测量员没有额外的费力就可获得。在该方法中，地球表面的曲率不能被忽略，即使对非常粗略的标高值。
Here a brief description of the various types of surveys will be given. Most of them employ plane rather than geodetic techniques.

这里将给出一个关于不同测量类型的简短描述。它们中多数采用平面技术而不是大地测量技术。
Land surveys are the oldest type of survey and have been performed since earliest recorded history. They are plane surveys made for locating property lines（地籍线）, subdividing land into smaller parts（分割土地）, determining land areas and any other information involving the transfer of land from one owner to another（土地产权转移）. These surveys are also called property surveys, boundary surveys, or cadastral surveys.

土地测量是最老的测量类型，自从最早有历史记载以来就已有之。它们属于平面测量方法，用以定位地籍线、分割土地、确定土地面积以及其他包括土地产权转移在内的信息。这些测量也称为地籍测量、边界测量或地产测量。
Topographic surveys（地形测量）are made for locating objects and measuring the relief（地貌）, roughness（粗糙度）, or three-dimensional variations of the earth’s surface. Detailed information is obtained pertaining to（关于）elevations as well as to the locations of man-made and natural features（人工和自然地物） (buildings, roads, streams, and so on) and the entire information is plotted on maps (called topographic maps).

地形测量用以定位物体以及测出地球表面的地貌、粗糙度或三向空间的变化。在得到了关于人工和自然地物（建筑物、道路、河流等）的标高和位置的详细信息后，将全部的信息绘在地图上（称为地形图）。
Route surveys（路线测量）involve the determination of the relief and the location of natural and artificial objects along a proposed（拟定的）route for a highway, railroad, canal, power line（输电线）, or other utility（应用）. They may further involve the location or staking out（放样）of the facility and the calculation of earthwork quantities（土方工程量）.

路线测量包括确定自然和人工的物体如公路、铁路、运河、输电线或其他应用沿着拟定路线的地貌和位置。它们可进一步包括设施的定位或放样，并计算土方工程量。
City survey are made within a given municipality for the purpose of laying out（定位）streets, planning（布置）sewer systems（排水系统）, preparing maps, and so on. When the term is used, it usually brings to mind（使人想起）topographic surveys in or near a city for the purpose of planning urban expansions or improvements.

城市测量是在一个特定的城市范围内用以定位街道、布置排水系统以及制作地图等。当采用该术语时，它通常使人想起在一个城市中或城市边进行的地形测量，用以规划城市的扩张和改进。
Construction surveys are made for purposes of locating structures and providing required elevation points during their construction. They are needed to control（指导）every type of construction project.

建筑测量用以确定建筑的位置，并在施工期间提供所需的标高点。它们被需要用来指导每种建筑工程。
Hydrographic surveys（水文测量）pertain to（适合）lakes, streams, and other bodies of water（水域）. Shore lines（海岸线）are charted, shapes of areas beneath water surface are determined, water flow（水流量） of streams is estimated, and other information needed relative to（相对于）navigation, flood control（防洪）, development of water resources, and so on, is obtained. These surveys are usually made by a governmental agency. When hydrographic and topographic surveying are combined the resulting surveys are sometimes called cartographic survey（地图制图测量）.
水文测量适合于湖泊、河流以及其他水域。绘出海岸线、确定水面下区域的形状、估计河流的水流量以及得到其他相对于航海、防洪、水资源发展等所需要的信息。这些测量通常由政府机构进行。当水文测量与地形测量结合起来形成的测量有时称为地图制图测量。
Marine surveys（海洋测量）are related to hydrographic surveys but they are thought to cover a broader area. They include the surveying necessary for offshore platforms（近海平台）, the science of navigation, theory of tides（潮汐学说）as well as the preparation of hydrographic maps and charts（海图）.