Angular Error Of Closure Example
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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 were most likely Apply an angular error of closure formula average correction to each angle Or a combination Never make an adjustment
Angular Closure Glaucoma
that is smaller than the measured accuracy DETERMINING BEARINGS OR AZIMUTHS Requires the direction of at least one line
Angular Closure Compiler
within the traverse to be known or assumed For many purposes, an assumed direction is sufficient A magnetic bearing of one of the lines may be measured and used as the reference
Angular Closure Compiler Advanced
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 projection on the east-west meridian and is equal to the length of the line times angular form error 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' 203.00 +202.91 -6.02 E 306° 54' 647.02 +388.48 -517.41 A MISCLOSURE -0.71 +0.53 ADJUSTMENT OF LATITUDES AND DEPARTURES Compass (Bowditch) Rule ADJUSTMENT OF LATITUDES AND DEPARTURES Station Azimuth Length Latitude Departur
set at zero, and a backsight to the preceding station is taken. The instrument is then turned on its upper motion until the advance station is sighted and the interior angle is observed. All interior angles is generally observed twice, once with angular error object telescope direct and other with the telescope reversed. Immediately after completion of observation, an arithmetical angular error logging check on the angular error of closure should be performed to detect any blunder or excessively large error in angular measurement.
angular error access to restricted uri denied Figure 28.6 shows an interior-angle closed traverse that originates at point A lying on the line PQ having a known azimuth of 42° 00' 00" as determined from a previous survey. In this traverse, point A was occupied first https://engineering.purdue.edu/~asm215/topics/travcalc.html and an angle was observed between line PQ and traverse line AB. The angle is observed to be 18° 00' 00". After the interior angle at A was observed, points B, C, D and E were occupied and interior angles was observed by method of repetition (at least twice) at each traverse station. Directions for the traverse sides are reckoned using the angle QAB turned from the line of known azimuth PQ to line AB. Thus, the azimuth of http://nptel.ac.in/courses/105107122/modules/module9/html/28-18.htm line AB is 42° 00' 00" + 18° 00' 00"= 62° 00' 00". To check the angular closure, azimuths are calculated from previously known azimuth of a line. The azimuth of each succeeding traverse line is computed by adding the clockwise interior angle or subtracting the anti-clockwise interior angle to the back azimuth of the preceding line. Thus, W.C.B. of a traverse line = Back W.C.B. of the preceding line ± included angle --------------------- (Equation 28.2) where + for clockwise interior angle and - for anti-clockwise interior angle. Further, 360° needs to be subtracted from computed W.C.B., if it is more than 360° and to be added, if the computed value is negative. The azimuth of each succeeding traverse line is then calculated by using Eq 28-2 and are as shown in column (3) of Table 28.4. In this method also there are two ways for finding the error of closure in a traverse observation. These are Azimuth adjustment method Interior angle adjustment method In azimuth adjustment method, the computed azimuth of the starting side is checked with its priori observed value. If both the values agrees, there is no error in the measurements for traverse. Otherwise there is error in measurement. To remove the error, a correction equal in magnitude but opposite in nature to the error of closure is distributed to the computed azimuth to find corrected azimuth. Figure 28.7 illustrates the compbe down. Please try the request again. Your cache administrator is webmaster. Generated Fri, 30 Sep 2016 14:59:12 GMT by s_hv978 (squid/3.5.20)