Needless to say,either the distance measurements or the angles could be in error. of the starting point. An Excel workbook showing these correction methods is available here. for every set up of the instrument, and then obtaining the reduced level of point with reference to the respective plane of collimation. 23. Any deviation from Follow techniques that will help detect and eliminatealltheblunders. It may be given in terms of the angle of elevation from the horizontal plane, in terms of the percentage of deviation from the horizontal line, or simply in terms of the ratio of its "rise to run" or "unit rise in run". The sleep calculator can help you determine when you should go to bed to wake up happy and refreshed. .{LR~f=ch\K[*kPti,sheCUX]&Pmvt2k? Take the total length of your string and divide it by the length of your level. distances so that out shape meets all the geometric criteria. The average computed provides more accurate reading. Recall our formula: H = h - N Where: H = the orthometric height we want to know h = 102.451 meters N = -22.835 meters Therefore, our calculation is this: H = (102.451 meters) - (-22.835 meters) But, first, start counting the contour lines from the . Thus, a = L f X a ( ) (3 . Average Correction Method. Use the length of both your string and level to calculate the difference in elevation between your posts. So, if one leg is 50% of the total traverse, you would apply half the error in X and half the error in Y to the end point of that leg. Use our K-factor calculator to determine the position of the neutral axis in the sheet of metal you are planning to bend. The definition also includes an elevation at a benchmark in Rouses Point, NY (next to Lake Champlain), which was accepted as fixed by the U.S. and Canada in 1925. Also, the elevation resulting from the application of both an orthometric correction and an adjustment correction to a preliminary elevation. In this method the coordinate error is distributed in proportion to the length of Also, the triangles that make up the quadrilateral should all The grade would be 0.06. We are interested in getting the angle between the horizontal plane and the plane of incline. School of PE representative will contact you ASAP, Copyright The difference in their staff reading indicates a rise or fall according to as any staff reading is smaller or greater than that at the preceding point. This is acceptable for use in local surveys due to the relatively short distances involved. Surveying, the following strategies must be followed: This is where all the angles and distances in a quadrilateral are measuredrepeatedly and averaged for accuracy. The slope is the quotient of the change in the values of y and the change in the values of x. The perfect snowman calculator uses math & science rules to help you design the snowman of your dreams! Terrain grades less than 1 (terrain grade <1) mean the slope is gentle. When the level rod is next placed on a new point as shown in figure 12, we can thencalculate the elevation of this point. and B.B of all lines is exactly 180, we can find the angles and bearings in a shorter way as . Elevation dimensions referenced to mean sea level (MSL) 3. Explain how to peg a level and calculate the collimation correction of a properly adjusted level. F.S. 1. hTQn0[t#N&-4iwES,D):xG(7.t4=Nv'srG. Setting up tripod (from Leica T105/T110 user manual Theodolite setup We call an angle that goes up from the horizontal line an "angle of elevation", while those that go down are the "angle of declination." You'll learn the correction formulas in the course, but here are some rules of thumb to remember: There are two other corrections that you should also be aware of, and those are for. - F.S. Calculate HI = BS + E (A) = 1.89 m + 100 m = 101.89 m. Find the elevation of turning point C as E (C) = HI-FS = 101.89 m - 0.72 m = 101.17 m. 7. Bulk Elevation Point Query Service. This permits calculating the elevation of point 0+00 as 102.31. elevation, field An elevation obtained from computations using measurements of elevation made in the field (on the ground). p. 125-142. Reduced here means equating and level means elevations. You need to compare that value with what the 12B geoid height was for the same location. The short 350 m long street is a real challenge to walk up! Simpler ways of adjusting traverses are shown in many Geology field methods texts. We can plot the averages of the terrain grades to compose a contour map. and the last R.Ls. Three-dimensional positions of points What positions do surveyors measure? i.e. Measuring distances alone in surveying does not establish the location of an object. 17K views 3 years ago Hello Guys in today's lecture i will show you the easiest way to make a surveying sheet in Excel. In this method, the coordinate error is distributed in proportion to the amount that Then simply multiply the decimal by 100 to find the percentage. The data mapped in surveying can be used for many purposes, from defining boundaries in legal documents to determining the best route to run utilities or construct a road. However - not pulling it tight will provide a higher value than this actual value because the tape will sag due to gravity. elevation, spot A point on a map or chart whose height above a specified reference datum is noted, usually by a dot or a small sawbuck and elevation value; spot height. Proper care in the use, storage, transportation and adjustment of the equipment is a major factor in the successful completion of a survey. To calculate the slope as a percentage, take the argument of the arctangent function and multiply it by 100: So how to calculate the contour interval becomes a useful skill for the contour line. The most common datum used is Mean Sea Level. document.write(new Date().getFullYear()); School of PE | Privacy Policy, This website uses cookies to ensure the best experience possible. In traverse survey, latitude and departure, checks in a closed traverse, closing error, relative precision, bowditch's rule, transit rule are details discuss. Eliminate or correct all systematic errors by frequent calibration and adjustment of the instruments minimize the random errors by using good instrumentsandfieldprocedures. Automatic Level for Measurement of Angles and Elevation There are three checks for arithmetical accuracy. It is used for longitudinal and cross levelling operations. So, if one leg is 50% of the total traverse, you would apply half the error in X and half the error in Y to the end point of that leg. Needless to say, earthquake (Cruikshank and other, 1996; Johnson and others, 1997), is a braced A clinometer is like a mini telescope with a protractor attached to its side. Horizontal, slope, and vertical What distances do surveyors measure? This will have coordinates of (0,0,0). By rejecting non-essential cookies, Reddit may still use certain cookies to ensure the proper functionality of our platform. A properly-oriented level defines a line parallel to the geoid surface at that point (Van Sickle, 2001). elevation, adjusted The elevation resulting from the application of an adjustment correction to an orthmetric adjustment correction to an orthometric elevation. Start from there. !-----. Use the square feet to cubic yards calculator to convert between square feet and cubic yards. Set up the level and measure BS = 1.96 m, and then FS = 0.87 m. distance between points. xcd```d`.7S`Y$X @b'#{ )$0029OJ0``b`h h Crosshairs can be adjusted using knob on side of level C. Record this elevation as the starting backsite (B.S.) do you have any elevation info and a reading from a benchmark? This elevation grade calculator determines and expresses, in four different ways, the slope of an earthen surface. workbook is also available for making these adjustments to a quadrilateral. How to figure out elevation grade? endstream endobj 188 0 obj <> endobj 189 0 obj <> endobj 190 0 obj <>stream Collins, 848 p. Smith & Varnes (1987), Least-squares adjustment of triangles and quadrilaterals in 125 0 obj <>stream Traditionally, elevations for a topographic survey are collected using some type of regular grid system Using the elevation data and the grid system, a three-dimensional model of the cut-and-fill volumes can be or Quadrilateral. Symbol Type . The difference. On the other hand, we can get the vertical distance by using optical devices, such as a surveyor's transit paired with a leveling rod. Horizontal and Vertical Curves in Surveying. 1. Copies of FORTRAN programs from Smith & Varnes are If B.S. What needs to be taken into account when measuring with a level or with a . that is a measure of error. This will have coordinates of If you examine the Deps and DMDs computations above, you should see a pattern to the computations. Other more sophisticated digital gadgets can now help obtain the slope of a particular surface. endstream endobj startxref The arctan function is the inverse of the tangent function with the slope as its article. The quadrilateral is then measured at some laterdate and strain calculated from the change in shape of the quadrilateral. Zhang Jiaqi, Early starts and green veg: How China bec, Human Growth Hormone : Human Growth Hormone Benefits |, Up Top Boss - Reggae Sumfest Teejay The Up Top Boss Fa, How To Space Out Instagram Captions - How to put space, Read Now Download eBook details Title: Advance. = Last R.L. Or: Aside from this, we can also express grade in terms of angles. A foresight is the elevation readingof a point of unknown elevation. Therefore, for bm 16, the adjusted elevation is 134.851 0.003 = 134.848. 1) BS (Back Sight) The first reading of staff in surveying taken by the first placing of levelling machine is known as back sight-reading. of B.M. Up Top Boss - Reggae Sumfest Teejay The Up Top Boss Facebook : Steph and ash discuss the top 10 interview mistakes they see on a regular basis. Move to a second levelling station, LS2, about halfway between C and B. of the preceding point. The most complete adjustment - First R.L. The plans show the following typical section. Let's assume that the road has 12 meters of rise for every 200 meters of run. Press the legs into the ground. From the nw corner, use the angle between lines from the nw to ne corner and nw to sw corner. = Last R.L. [Download] "Advanced Dairy Chemistry, Volume 2" by Paul L. H. McSweeney, Patrick F. Fox & James A. O'Mahony # Book PDF Kindle ePub Free. 122 0 obj <> endobj Learn how to fill out differential leveling notes in this video.VISIT OUR WEBSITE AT http://www.afmatheng.com/ !! Knowing an area's elevation grade offers many advantages over not knowing it at all. An example of a strong shape often used for studying deformation,such as on a landslide (baum and others, 1988; For aquadrilateral you would perform the following calculations: Any deviation fromthat is a measure of error. the height of the level is simply the height of the benchmark of known elevation added to the backsight reading of rod 1. A sighting with a level back to a point of known elevation. Powered by First, the H.L is calculated by adding the back sight of the R.L. If you start with a benchmark of known elevation, it's all very simple. 587. quadrilateral you would perform the following calculations: This closure error can then be adjusted to zero using either the compass rule or the F.S. method for solving over-determined systems is the methods of least-squares. The Reduced level can be calculated by two methods, It consists of finding the elevation of the plane of collimation i.e. The horizontal positions of the points can be obtained in a number of different ways in addition to traversing. hTYPd+ elevation meter A mechanical or electromechanical device on wheels that measures slope and distance, and automatically and continuously integrates their product into difference of elevation. A lines ellipsoidal length can be calculated by multiplying the lines horizontal distance and its elevation factor. Figure III-2. + elevation of benchmark (b.m.) endstream endobj 128 0 obj <>stream It is denoted as B.S. An outline of the method of general least squares is given in the following pdf format document (from the g423/523course web pages). This is done by. A smartphone, if equipped with adequate hardware like gyroscopic sensors, can accurately provide you with a surface's slope when you lay your it on the slope. P1 hold stadia rod on survey point #1. An example of a strong shape often used for studying deformation, endstream endobj of the preceding point. What info is given on the backsight and foresight? such as on a landslide (Baum and others, 1988; Johnson & Baum, 1987) or for from an shots. This reduced level is the term used in levelling. c6\hdpgkt'A7K[m)LI+lU4r~DLXfB yQA8B()|R\Wu?2*X i(/\Hz76>fg6"{\f Y4G7 [Fvm. The difference between the GNSS-derived orthometric adjusted height and the new NAVD 88 height decreased from 3.5 cm to -0.6 cm. About Land Surveyors United - Global Surveying Community Bringing together seasoned & aspiring surveyors in a premier online community with expert insights, resources & networking opportunities. Angles in the horizontal and vertical planes What angles so surveyors measure? Surveying engineer reads central value together with lower and upper. Figure 7 is a plot that depicts the differences at station Buffalo 2 using the modified NAVD 88 height. In this case, 33%. Surveying and Levelling. following the path of your traverse. Elevation closure error. Why do we need to know a particular terrain's elevation grade? Links to 3DEP Elevation Applications and Tools. It is a vertical distance above or below the datum plane. For a angle = arctan(rise/run) = arctan(1/2.86) = 19.27. Contour interval calculator - A contour interval in surveying is the vertical distance or the difference in the elevation between the two contour lines in a. . Calculate the elevation at the edge of shoulder. Then the elevation of the turning point can be calculated. It is used for earthwork calculations and other precise levelling operations. Firmly fix the tripod. could possibly construct several different triangles using the data. To calculate the slope of a line and to learn more about slopes in general, you can check our slope calculator. Repeat Step 4 for additional survey points (including the top of the staff gage and transducer) 6. = Rise fall = (First R.L.) From the se corner, use the angle between lines from the se to sw corner and se to ne corner to calculate the coordinates of the ne corner. %PDF-1.2 % Focusing it on the leveling rod (which is like a huge ruler) will give a reading. This procedure is being repeated to establish the elevation of other points until TP1 at 0+70. The focusing screw is then adjusted until the object's picture looks clear and crisp, with no movement . For aquadrilateral you would perform the following calculations: The elevation is calculated by subtracting theforesight rod reading from the height of instrument. ct\"86`{xA`0(Ed$L](*Gjxq>u:,)P JNkk/^7Ri%?e,nXe;O(>oyb;p659'_}~QbohCOq-J[Ld_284>6UN6Cd:IE94+{VF]_ 2G+ 233 0 obj <>stream Additionally, you may request sampled elevation data along paths, allowing you to calculate elevation changes along routes. In some localities, this is modified by a regional adjustment, e.g., the Pacific Northwest Supplemental Adjustment. It is a laborious method as staff reading of each point on the ground after the first is compared with that preceding it, and the difference of level entered as a rise or fall. Download Free PDF View PDF Download PDF TRAVERSE COMPUTATIONS AND ADJUSTMENTS Engr. Zhang Jiaqi, Early starts and green veg: How China became diving greats , Zhang jiaqi is a chinese diver. The quadrilateral is then measured at some later An excelworkbookis also available for making these adjustments to a quadrilateral. From the se corner, use the angle between lines from the se to sw corner and se to ne corner to calculate the coordinates of the ne corner. The difference between the sum of the back sights and the sum of the fore sights should be equal to that between the sum of rises and the sum of the falls as well as that between the first. Elevation grade (or slope) is the steepness, or degree of inclination, of a certain area of land. So add your BM (10.00' )and BS (5.35') that will give you your HI which is 15.35' then you will read your SS let's say it's 4.81' you subtract your FS (4.81') from your HI (15.35') which is 10.54' the method for getting your SS and FS is the same it's just your FS will become your next BS. Fr>qj315]zS/Bp For example, for instrument location 1, a backsight of 7.13 ft (click) is recorded to the BM. Starting with line AB and use Equation G-4 to computed the DMDs. This is later leveled to start the surveying. Thanks for contacting us. Two-dimensional points 2. To learn more about how to find the slope of the terrain (or of the ground in general), keep reading. Slope can be calculated as a percentage which is calculated in much the same way as the gradient. An elevation above the geoid is called an orthometric height. If you want to know the angle of the slope, input the value in the arctangent function: If you want to know the slope as a percentage, multiply the ratio by. There are several different ways to measure heights. 0 For example measuring two angles and one. An excelworkbookis also available for making these adjustments to a quadrilateral. With the Elevation API, you can develop hiking and biking applications, positioning applications, or low resolution . 4. 0{La79-`m1p@Q3F)ojgrzPA \wnJi&2ac1t3v@TIR~=Y?=4xT_sr/[j;}tOPa=Mg7V>+t\a9,ZOKh]lVPohZ,wKe%j/Zf& of the starting point. To adjust for this, consider the X and Y components of the misclosure error, and then apply those proportionally to each leg. Note that X and Y are handled separately for this. Therefore, for bm 16, the adjusted elevation is 134.851 0.003 = 134.848. which will have leveling and different elevations already calculated. The vertical datum is accessible through benchmarks anchored to the ground and stable structures. traverse lines. When the level rod is next placed on a new point as shown in figure 12, we can thencalculate the elevation of this point. of previous point + (rise or fall), To check B S. F.S. The formula gives the slope defined as an angle: Johnson, A. M., and Baum, R. L., 1987, BASIC programs for computing displacement, An Excel A line's ellipsoidal length can be calculated by multiplying the line's horizontal distance and it's elevation factor. deformation zone. . We also have an A slope where each horizontal meter corresponds to a vertical meter has slope 1, which multiplied by 100 returns the value 100%. Then turns and takes a foresight reading on 0+00 point. In surveying, the distance between two points means the a. Horizontal or level distance b. Slope distance . On the other hand, terrain grades that are greater than one (terrain grade >1) indicate that the terrain is steep. "CA$~,R&j&&,t``T" ?X$DeAGI[xTZV,Hc.F2Ir F The crosshair can be accurately aligned to . The difference, if any, will be the change in your derived NAVD88 orthometric height (elevation). On the other hand, we call the change in the x values the "run", since it runs along the horizontal axis. In this method, the difference between consecutive points is calculated by comparing each point after the first with that immediately preceding it. (H.I.) Grade values are pretty easy to understand. Photo by Denise Jans on Unsplash Mathematics. From the SE corner, use the angle between lines from the SE to SW corner and SE to NE Differential leveling under agricultural survey is a type of surveying that uses a level and staff to measure the elevation changes between two or more points to determine the difference in height. note: lec 2 and above wala akong nilagay na solution para hindi makupya techniques ko. The difference between this calculated coordinate and (0,0,0) is your error of closure. A surveyor's transit has an inbuilt telescope that can be rotated laterally or vertically over a tripod. 2 Adjustments of Level Circuits A 100.24 0.5 -7.31 3.0 D 107.55 0.8 -8.47 . This relationship gives us the popular equation that you might have already heard before: "slope is equal to rise over run." the difference between the sum of back sights and sum of fore sights should be equal to the difference of the first and last R.Ls. jIb Transcribed image text: SURV 2221 Branham Example Stadia Problem: Horizontal Distance: (H) = (K) (1) [ (sin of Zenith Angle) Difference in Elevation: (V) = (K) (1) (sin Zenith Angle) (cos Zenith Angle) K100 the stadia interval, (difference between top stadia hair and bottom stadia hair). Wolf, P. R., and Ghilani, C. D., 1997, Adjustment computations: Statistics and least For instance, 3" rise divided by 36" run = .083 x 100 = an 8.3% slope. Some more specifications about this method: As it involves only a few calculations, there is a considerable saving of labour and time in the case of intermediate readings. 13. We can translate this reading into the elevation between the leveling rod and the transit. An example of a strong shape often used for studying deformation,such as on a landslide (baum and others, 1988; For example measuring two angles and one. Using step 8 as a guideline, enter all measurements in a table and calculate the results as shown in the example below. . Since the observed elevation of the closing bm is greater than its known elevation, the adjustments are subtracted from the intermediate bms. The whole mechanism is placed on a plate that is attached to a tripod. The Elevation API provides a simple interface to query locations on the earth for elevation data. Fix one corner of quadrilateral, say the sw corner. The staff is placed on the point whose benchmark is given. We call the change in the values of y "rise", since it is along the vertical axis. A surveyor's transit also has distinctive markings on its view that make it also able to measure horizontal distances when paired with a leveling rod. how to calculate adjusted elevation in surveying. When the instrument is shifted, a new plane of collimation is set up and the height of which is calculated by adding back sight reading to the R.L. Chain Survey Steps - Method for Performing Chain Surveying. Aside from expressing grade using ratios and angles, we can also determine it in terms of percentages - we only have to multiply its ratio value by 100 to get it. 7504.00 b. The fill is being supported by a retaining wall at the base and this wall will need to be of a variable height to accommodate the fill. In terms of angle of elevation, angles above 45 degrees are the steep ones, whereas angles below 45 degrees are relatively flat. Suspend the plumb-bob or release the laser mark (depends on the model). elevation of survey point = h.i. What are the main features of these instruments? - First R.L. Fix one corner of quadrilateral, say the sw corner. difference between F.B. One method for adjusting quadrilaterals is given by Smith & Varnes (1987). This is the platforms onto which the telescope and the spirit level are mounted. You can set the grade and determine the horizontal distance required to obtain the required change in a vertical distance, as well as obtain the angle of elevation. The lines are drawn around the lake or pond for the purpose of measuring property that abuts the water. possible changes (Moffitt, and Bouchard, 1992; Wolfe and Ghilani, 1997). crabapple vs cherry tree / a thunderstorm is a connection between what two spheres / a thunderstorm is a connection between what two spheres York, John Wiley & Sons, 564 p. Fix one corner of quadrilateral, say the SW corner. Measuring distances alone in surveying does not establish the location of an object. elevation factor The ratio of the radius of the earth (R) to the sum of the radius of the earth, a lines average orthometric height (H), and the geoidal separation (N). In equation form, it looks like this: If you don't have a calculator with this trigonometric function, don't worry, we already have it incorporated into our elevation grade calculator above. #D5M`LV2,s-Q"g2Ae8([#/lHJ/`hz%=x6a4`uu Lo9 pdP2H$XLE'{(/ D$,`/OUm\'?cNrTcNmY`/B:1L:$~-`/RM`=zNBp |#p1}2B`r([@5c{ZuY,YzeU0B 95FaOAJ*]/A!va. Note that X and Y are handled separately for this. From the ne corner, use the angle between lines from the ne to se corner and ne to nw corner to calculate the coordinates of the ne corner. How To Space Out Instagram Captions - How to put spaces in an instagram post caption. We can get the "run", or the change in the horizontal distance, by using a measuring tape. This process is repeated until all the R.Ls are worked out, and then the arithmetical check is applied. However, given the varying terrains and conditions for it, it's no surprise that accuracy can be hard to ensure in the field. calculated coordinate and (0,0,0) is your error of closure. Step (2) Multiply DMDs by Lats; add the products. Also, the elevation resulting from the application of both an orthometric correction and an adjustment correction to an orthometric elevation. Source: NSPS Definitions of Surveying and Associated Terms, used with permission. Apr 07, 2018. We need to locate the object in 3 dimensions. Here is the GEOID12B computation utility: A traverse is a survey where you have occupied each station and measured each angle and %PDF-1.5 % p$fm2d_p*`0t:k6f6m]K'-4 of surveying. Definitions of Surveying and Associated Terms. Horizontal distance. Surveying and Levelling. over-determined system. Before calculating the height of the instrument in surveying, we should know some important terms used for levelling. slope (percentage) = rise/run 100, Rather counterintuitively, a slope of 100% corresponds to an angle of 45. Assign the direction from the SW to the SE corners to be "east". Example DMD Traverse. Ss|L1 Horizontal length (distance) difference in height (elevation) angular direction 21 Assign the direction from the sw to the se corners to be east. Any deviation fromthat is a measure of error. Create an account to follow your favorite communities and start taking part in conversations. If In this method, the difference between consecutive points is calculated by comparing each point after the first with that immediately preceding it. The two main styles of surveying covered on this exam are stationing with tapes and using a total station to create a traverse. How To Calculate Adjusted Elevation In Surveying : From the se corner, use the angle between lines from the se to sw corner and se to ne corner to calculate the coordinates of the ne corner. However, GPS receivers cannot produce orthometric heights directly. corner to calculate the coordinates of the NE corner. The rise and fall method is the method of calculating the difference in elevation between consecutive points in levelling work. We need to locate the object in 3 dimensions. elevation factor - The ratio of the radius of the earth (R) to the sum of the radius of the earth, a line's average orthometric height (H), and the geoidal separation (N). After completing the traverse you should return to When the level rod is next placed on a new point as shown in figure 12, we can thencalculate the elevation of this point. A foresight is the elevation readingof a point of unknown elevation. It should be noted; the elevation for the newly relocated bench mark will only be published to the nearest 0.01 meter, or 0.1 feet, because the absolute elevation of the bench mark to be destroyed cannot be verified without incorporating other bench marks into the survey, as a check. of intermediate stations. dWMj{l$&TA (S>}g KqK@gz,*h`P;{ 8L?YuLA e_6{?W0bP y"`aE7=`CnZ}g$%oQoKAW4ly^xW HkKn7vS3Z)0\U0FDVI3 tO)X!=3Ssz Ms. Kelly is an experienced structural engineer with a focus on seismic risk. The angle of close traverse is balanced or adjusted such that they satisfy the required condition of the geometrical figure. from table] X Correction Factor = 8.97 x 0.9572 = 8.59 mg/L Determining saturation point with a "corrected" chart Record this elevation as the foresite (F.S.). For example measuring two angles and one side of a triangle is To figure out what is the total net cut/fill between stations 1+00 and 3+00. 2. Surveying, the following strategies must be followed: Johnson & baum, 1987) or for from anearthquake (cruikshank and other, 1996; Triangleor quadrilateral.note that the programs require isml routines. - F.S. The resulting slope for this value is considered neither steep nor flat but instead of an average grade. A traverse is a survey where you have occupied each station and measured each angle anddistance between points. we will also use formula's which is shown in the video above.Also Read the full Version here: https://civilengineering-global.blogspot.com/2019/07/how-to-create-surveying-sheet-in.htmlTo Watch More Lecture Videos Like This One:++++++++++++++++++++++++++++++++++++Subscribe To Youtube Channel: https://www.youtube.com/channel/UCnQUtOJ4ZpoTRsUJl0yVFTwLike Facebook Page: https://www.facebook.com/civilengineeringglobe++++++++++++++++++++++++++++++++++++Show your support by liking this video and comment below if you have any question or suggestions. You will find that point B is 2.82 m higher than point A and, therefore, that its elevation is E (B) = 100 m + 2.82 m = 102.82 m. 12. methods uses least-squares to adjust angles and distances so that you make the smallest Meander lines are run by surveyors for mapping and surveying purposes for a body of water. Jan 16, 2017. is negative then it is fall, R.L.= R.L. either the distance measurements or the angles could be in error. By accepting all cookies, you agree to our use of cookies to deliver and maintain our services and site, improve the quality of Reddit, personalize Reddit content and advertising, and measure the effectiveness of advertising.