--- title: "Closed loop/link traverse, grid plotting" subject: "Surveying II" chapter: 1 key: "semester_4/surveying_ii:closed-loop-link-traverse-plotting-grid" source: https://www.bctengineer.com/q/semester_4/surveying_ii/closed-loop-link-traverse-plotting-grid site: BCT Engineering --- # Closed loop/link traverse, grid plotting Surveying II · Chapter 1: Traversing - Asked in: 2076 Bhadra, 3+3 marks - Video: [Calculating Coordinates in a Close Traverse; When the length and bearing of all the lines are given](https://www.youtube.com/watch?v=k2_zGELQFDs) — CIVIL Solved - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_4/surveying_ii/closed-loop-link-traverse-plotting-grid - Whole chapter: https://www.bctengineer.com/md/semester_4/surveying_ii/chapter-1 ## Question Define closed loop and closed link traverse. Explain the plotting method of traverse by grid coordinates. ## Short answer A closed loop traverse starts and ends at the same station, forming a polygon; checks: angle sum (2n-4)×90°, ΣLat=0, ΣDep=0. A closed link traverse connects two known stations with known bearings, checked by bearing and coordinate closure. Grid plotting: choose scale, draw labeled grid, plot stations by coordinates using a scale from grid lines, join, verify lengths, then detail. ## Answer #### Closed loop and closed link traverse - **Closed loop traverse:** the traverse starts and ends at the same station and forms a polygon. Checks: sum of interior angles $=(2n-4)\times 90^\circ$, and $\Sigma\text{Lat}=0,\ \Sigma\text{Dep}=0$. - **Closed link (connecting) traverse:** the traverse starts at one known station and ends at another known station, both with known coordinates, and with known reference bearings at the two ends. Checks: the computed bearing of the last line must equal its known value, and the computed coordinates of the last station must equal the known ones. #### Plotting by grid coordinates 1. Choose a scale so that the whole traverse fits on the sheet (for example 1 cm = 10 m). Find the range of N and E values, i.e. maximum minus minimum, and divide by the scale to get the size of sheet needed. 2. Draw the grid of squares (the grid sheet) and label the grid lines with northing (vertical axis) and easting (horizontal axis) values, choosing an origin near the south-west corner so that all plotted values are positive. 3. Convert each station's independent coordinates to plotting units. For example, with scale 1 cm = 10 m, a station at $(N, E)$ is plotted $(E-E_0)/10$ cm along the east axis and $(N-N_0)/10$ cm along the north axis from the origin $(N_0, E_0)$. 4. Mark each station with a fine pencil dot, measuring its position from the nearest grid lines with a scale (no protractor is needed), and circle it with the station name. 5. Join the stations in order with thin lines, and check that each plotted line length, measured with the scale, agrees with the field length. This is a check against blunders. 6. Plot the details (offsets and radiations) from the stations, ink the map and add the title, scale, north arrow, legend and border. Advantage: each station is located independently by its coordinates, so plotting errors do not accumulate, and the closing check is automatic. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What defines a closed loop traverse? A. It starts and ends at two different known stations B. It starts and ends at the same station forming a polygon C. It has no angle measurements D. It is run only between two bearing-known lines Answer: B. A closed loop traverse returns to its starting station and forms a polygon. (Key point: Closed loop traverse) 2. What are the checks for a closed link traverse? A. Sum of interior angles = (2n-4) x 90° B. Computed bearing of the last line and computed coordinates of the last station match their known values C. Sum of latitudes alone equals zero D. Sum of exterior angles = 360° Answer: B. A link traverse joins two known stations with known end bearings, so the check is agreement of the computed last bearing and last-station coordinates with the known ones. (Key point: Closed link traverse checks) 3. In plotting by grid coordinates, why is the grid origin chosen near the south-west corner? A. So that all plotted coordinates are positive B. So that the scale becomes 1:1 C. So that the north arrow can be omitted D. So that bearings need not be measured Answer: A. Minimum N and E are subtracted so that all stations have positive plotting coordinates. (Key point: Choosing the origin and scale) 4. With scale 1 cm = 10 m, where is a station at (N, E) plotted? A. (N - E0)/10 along east and (E - N0)/10 along north B. (E - E0)/10 cm along the east axis and (N - N0)/10 cm along the north axis C. N/10 along east and E/10 along north D. By a protractor bearing and a scaled distance only Answer: B. Subtract the origin values and divide by the scale: east from E, north from N. (Key point: Station position from coordinates) ## Related in Surveying II - [Closed loop/link traverse, misclosure terms](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Aclosed-loop-link-traverse-misclosure) — Surveying II, chapter 1 - [Closed loop/link traverse, misclosure balancing](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Aclosed-loop-link-traverse-angular-misclosure) — Surveying II, chapter 1 - [Plotting coordinated traverse on grid paper](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Atraverse-plotting-grid-paper) — Surveying II, chapter 1, asked 2× - [Link traverse B to M, coordinates X and Y](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Alink-traverse-bowditch-x-y-between) — Surveying II, chapter 1 - [Consecutive, independent coordinates, plotting](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Aconsecutive-independent-coordinates-plotting) — Surveying II, chapter 1 - [Closed/open traverse, consecutive, independent coordinates](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Aclosed-open-traverse-consecutive-independent) — Surveying II, chapter 1 ## Related in other subjects - [Angle misclosure, closed link traverse AT1-ET2](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Aclosed-link-traverse-at1-et2) — Surveying I, chapter 4 - [Corrected bearings, closed link traverse T1-T2](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Aclosed-link-traverse-t1-t2-corrected-bearings) — Surveying I, chapter 4 - [Closing error; plotting methods in compass traverse](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Aclosing-error-plotting-methods) — Surveying I, chapter 4 - [Link traverse XP to TY, angles to right](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Alink-traverse-xp-ty-angles-to-right) — Surveying I, chapter 4