Angular Error In Traverse
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example of a calculation involving interior angles is available. ADJUSTING ANGLES Adjustments applied to angles are independent of the size of the angle Methods of adjustment: Make larger corrections where mistakes link traverse angular misclosure were most likely Apply an average correction to each angle Or
Closing Error In Traverse
a combination Never make an adjustment that is smaller than the measured accuracy DETERMINING BEARINGS OR AZIMUTHS Requires angular form error the direction of at least one line within the traverse to be known or assumed For many purposes, an assumed direction is sufficient A magnetic bearing of one of
Angular Error Object
the lines may be measured and used as the reference for determining the other directions For boundary surveys, true directions are needed LATITUDES AND DEPARTURES The latitude of a line is its projection on the north-south meridian and is equal to the length of the line times the cosine of its bearing The departure of a line is its angular error logging projection on the east-west meridian and is equal to the length of the line times the sine of its bearing The latitude is the y component of the line and the departure is the x component of the line LATITUDES AND DEPARTURES CLOSURE OF LATITUDES AND DEPARTURES The algebraic sum of all latitudes must equal zero or the difference in latitude between the initial and final control points The algebraic sum of all departures must equal zero or the difference in departure between the initial and final control points CALCULATION OF LATITUDES AND DEPARTURES Using bearings Station Bearing Length Latitude Departure A N 26° 10'E 285.10 +255.88 +125.72 B S 75° 25'E 610.45 -153.70 +590.78 C S 15° 30'W 720.48 -694.28 -192.54 D N 1° 42'W 203.00 +202.91 -6.02 E N 53° 06'W 647.02 +388.48 -517.41 A MISCLOSURE -0.71 +0.53 CALCULATION OF LATITUDES AND DEPARTURES Using azimuths Station Azimuth Length Latitude Departure A 26° 10' 285.10 +255.88 +125.72 B 104° 35' 610.45 -153.70 +590.78 C 195° 30' 720.48 -694.28 -192.54 D 358° 18'
should theoretically equal the product of 180° (n – 2), n being the number of sides in the polygon described by the traverse. A prescribed MAXIMUM ANGULAR ERROR OF CLOSURE is
Angular Error Of Closure Formula
stated in terms of the product of a given angular value times the
Angular Error Access To Restricted Uri Denied
square root of the number of interior angles in the traverse. Again, if we use the traverse shown in figure angular error interceptor 13-27 as an example, the prescribed maximum angular error of closure in minutes is 01 fi because the figure has three interior angles. The sum of the interior angles should be 180°. If the https://engineering.purdue.edu/~asm215/topics/travcalc.html sum of the angles as actually measured and recorded is 179°57´, the angular error of closure is 03´. The maximum permissible error of closure is the product of 01´ times the square root of 3, or about 1.73´. The prescribed maximum angular error of closure has therefore been exceeded.
Meeting Precision Specifications The following specifications are intended to give you only a general idea of the typical precision http://www.tpub.com/engbas/13-23.htm requirements for various types of transit-tape surveys. When linear and angular errors of closure are specified, it is understood that a closed traverse is involved. For many types of preliminary surveys and for land surveys, typical precision specifications may read as follows: l Transit angles to nearest minute, measured once. Sights on range poles plumbed by eye. Tape leveled by eye, and standard tension estimated. No temperature or sag corrections. Slopes under 3 percent disregarded. Slopes over 3 percent measured by breaking chain or by chaining slope distance and applying calculated correction. Maximum angular error of closure in minutes is 1.5 . Maximum ratio linear error of closure, 1/1000. Pins or stakes set to nearest 0.1 ft. For most land surveys and highway location surveys, typical precision specifications may read as follows: l Transit angles to nearest minute, measured once. Sights on range poles, plumbed carefully. Tape leveled by hand level, with standard tension by tensionometer or sag correction applied. Temperature correction applied if air temperature more than 15° different from standard (68°F). Slopes under 2 percent disregarded. Slopes over 2 percent measured by breaking chain or by applying approximate slope correction to slope distance. Pins or stakes set to nbe down. Please try the request again. Your cache administrator is webmaster. Generated Fri, 30 Sep 2016 15:23:43 GMT by s_hv1002 (squid/3.5.20)
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