Surveying part 1

• Surveying is the art and science of determining angular and linear measurements to establish the form, extent, and relative position of points, lines, and areas on or near the surface of the earth through applied mathematics and the use of specialized equipment and techniques.
• Plane-Surveying are surveys in which the earth is considered to be a flat surface, and where distances and areas involved are of limited extent that the exact shape of earth is disregarded.
• Geodetic-Surveying are surveys of wide extent which take into account the spheroidal shape of the earth.
• Cadastral-Surveys are usually closed surveys which are undertaken in urban and rural locations for the purpose of determining and defining property lines and boundaries, corners and areas.
• City-Surveys are surveys of the areas in and near a city for the purpose of planning expansions or improvements, locating property lines, fixing reference monuments, determining the physical features and configuration of the land, and preparing maps.
• Construction-Surveys are surveys which are undertaken at construction site to provide data regarding grades, reference lines, dimensions, ground configuration, and the location and elevation of structures.
• Forestry Surveys are a type of survey executed in connection with forest management and mensuration, and the production and conservation of forest lands.
• Hydrographic Surveys refer to surveying streams, lakes, reservoirs, harbors, oceans, and other bodies of water.
• Industrial Surveys, also referred to as optical tooling, is a method of making extremely accurate measurements for manufacturing processes.
• Mine Surveys are surveys which are performed above and below ground to guide tunneling and other operations associated with mining.
• Photogrammetric Surveys are a type of survey which makes use of photographs taken with specially designed cameras either from airplanes or ground stations.
• Route Surveys involve the determination of alignment, grades, earthwork quantities, location of natural and artificial objects in connection with the planning, design, and construction of highways, railroads, pipelines, canals, transmission lines, and other linear projects.
• Topographic Surveys are those surveys made for determining the shape of the ground, and the location and elevation of natural and artificial features upon it.
• A measurement is the process of determining the extent, size or dimensions of a particular quantity in comparison to a given standard. In surveying, measurements are usually concentrated on angles, elevations, lines, areas, and volumes.
• In surveying, measurements are usually concentrated on angles, elevations, lines, areas, and volumes.
• Direct-measurement is a comparison of the measured quantity with a standard measuring unit or units employed for measuring a quantity of that kind.
• An error is defined as the difference between the true value and the measured value of quantity. It is a deviation of an observation or a calculation from the true value and is often beyond the control of the one performing the operation.
• Mistakes are inaccuracies in measurements which occur because some aspect of a surveying operation is performed by the surveyor with carelessness, inattention, poor judgment, and improper execution. They are not classified as errors because they usually are so large in magnitude compared to errors.
• Personal Errors are errors arising principally from limitations of the senses of sight, touch, and hearing of the human observer which are likely to be erroneous or inaccurate.
• Indirect-measurement is done when it is not possible to apply a measuring instrument directly to a quantity to be measured. In this type of measurement, the observed value is determined by its relationship to some other known values.
• The most-probable-value of a group of repeated measurements made under similar conditions is the arithmetic mean or the average.
• Theory-of-Probability states that small errors occur more often than large ones and that they are more probable; large errors happen infrequently and are therefore less probable; for normally distributed errors, unusually large ones may be mistakes rather than accidental errors;Positive and negative errors of the same size happen with equal frequency; that is, they are equally probable;The mean of an infinite number of observations is the most probable value.
• Instrumental Errors are errors due to imperfections in the instruments used, either from faults in their construction or from improper adjustments between the different parts prior to their use.
• Natural Errors are errors caused by variations in the phenomena of nature such as changes in magnetic declination, temperature, humidity, wind, refraction, gravity, and curvature of the earth.
• Precision refers to the degree of refinement and consistency with which any physical measurement is made. It is portrayed by the closeness to one another of set of repeated measurements of a quantity
• Accuracy indicates how close a given measurement is to the absolute or true value of the quantity measured. It implies the closeness between related measurements and their expectations
• Surveying-field-notes constitute the only reliable and permanent record of actual work done in the field.
• The residual, which is sometimes referred to as the deviation, is defined as the difference between any measured value of a quantity and its most probable value.
• Summation-of-Errors is if several measured quantities are added, the probable error of the sum is given by the square root of the sum of the squares of the separate probable errors arising from the several sources.
• Product-of-Errors is for a measured quantity which is determined as the product of two other independently measured quantities.
• The probable-error is a quantity which, when added to and subtracted from the most probable value, defines a range within which there is a 50 percent chance that the true value of the measured quantity lies inside the limits thus set.