--- title: "Methods of plane table survey" subject: "Surveying I" chapter: 6 key: "semester_3/surveying_i:methods-of-plane-table-survey" source: https://www.bctengineer.com/q/semester_3/surveying_i/methods-of-plane-table-survey site: BCT Engineering --- # Methods of plane table survey Surveying I · Chapter 6: Plane Table Survey - Asked in: 2081 Bhadra, 4 marks; 2081 Baisakh, 4 marks; 2068 Chaitra, 4 marks; 2063 Baisakh, 8 marks; 2061 Baisakh, 8 marks; 2059 Chaitra, 10 marks (asked 6 times) - Video: [Methods of plane tabling! Methods of plane table! Radiation method! Intersection method](https://www.youtube.com/watch?v=dbz17G_6Jm4) — Smart Engineer - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_3/surveying_i/methods-of-plane-table-survey - Whole chapter: https://www.bctengineer.com/md/semester_3/surveying_i/chapter-6 ## Question What are the methods of plane table survey? Explain them (describe any two). ## Short answer The four methods are radiation, intersection, traversing, and resection. Radiation: rays drawn from one station, distances scaled along them. Intersection: rays from two stations on a plotted base line intersect to fix a point. ## Answer The four methods are: 1. **Radiation** - rays are drawn from one station to the points to be plotted and distances are measured and scaled along them. 2. **Intersection** (triangulation) - a point is fixed by drawing rays to it from two stations at the ends of a plotted base line. 3. **Traversing** - the table is set up at successive stations of a traverse; each new station is plotted by radiation and the table is oriented by back-sighting. 4. **Resection** - the table station itself is located by drawing rays *back* from known plotted points to it (two-point and three-point problems). #### Radiation method The table is set up at one station O, from which all the points to be plotted are visible. 1. Level, centre and fix the sheet; mark the point **o** on the sheet for O. 2. Pivot the alidade on **o** and sight each station A, B, C, D in turn; draw a ray towards each. 3. Measure the distances OA, OB, OC, OD with a tape and mark them to scale along the rays to get a, b, c, d. 4. Join a, b, c, d to obtain the plan. ```text b c \ / \ ray / a ------- o (table) -------- d ``` **Suitability:** small areas with open ground, where all points can be seen from one station and distances can be measured easily. It is the base of detailing by plane table. #### Intersection method Two stations A and B (the ends of a base line) are chosen so that the point P to be located is visible from both. 1. Set the table at A, orient it by compass, and plot **a**. Sight B and draw the ray; measure AB and plot **b** to scale. 2. Sight P from a and draw the ray aP (also rays to the other points). 3. Shift to B, centre **b** over B, and orient the table by back-sighting A along the line ba. 4. Sight P again from b and draw the ray bP. The intersection of the two rays is the plotted point **p**. ```text p / | \ / | \ / | \ a ------------- b (stn A) base (stn B) ``` **Suitability / advantages:** - Used for locating inaccessible points (across rivers, hills, buildings, a far-away church spire, etc.) where distance cannot be measured. - Only one linear measurement (the base line) is needed; many points can be fixed quickly. - A third ray from another station checks the plotted point. - Good intersection angle (about 60 to 120 degrees) is needed for accuracy. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Which are the four methods of plane table survey? A. Triangulation, levelling, traversing, tacheometry B. Radiation, intersection, traversing, resection C. Radiation, chaining, offsetting, resection D. Intersection, bearing, closing, resection Answer: B. These are the four standard methods. (Key point: Four methods) 2. What does resection do? A. Measures the base line B. Plots from a single station C. Locates a point by rays from two stations D. Locates the table station by rays drawn back from known plotted points Answer: D. In resection the occupied station itself is located. (Key point: Resection) 3. What is needed for radiation? A. Three known points B. Two stations and a base line C. Rays from one station and measured distances scaled along them D. A traverse Answer: C. Rays are drawn from one station and distances are scaled along them. (Key point: Radiation) 4. How is point p fixed by intersection? A. Draw one ray and a distance B. Resect from three points C. Measure distance from a D. Rays from a and b, the table oriented at b by back-sighting a Answer: D. The intersection of two rays from the ends of the base line gives p. (Key point: Intersection) ## Related in Surveying I - [Working principle of plane table survey](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Aworking-principle-plane-table) — Surveying I, chapter 6 - [Plane table principles; orientation by back sighting](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Aorientation-back-sighting) — Surveying I, chapter 6, asked 4× - [Plane table principles; advantages, disadvantages](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Aprinciples-adv-disadv-plane-table) — Surveying I, chapter 6, asked 2× - [Methods of orienting plane table](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Amethods-of-orienting-plane-table) — Surveying I, chapter 6 - [Two-point resection in plane tabling](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Atwo-point-resection-plane-table) — Surveying I, chapter 6 - [Advantages and disadvantages of plane tabling](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Aadvantages-disadvantages-plane-table) — Surveying I, chapter 6, asked 2× ## Related in other subjects - [Overall heat transfer coefficient: two-layer plane wall](https://www.bctengineer.com/question.md?key=semester_2%2Ffundamental_of_thermodynamics_and_heat_transfer%3Acomposite-plane-wall-two-layers-overall-u) — Fundamental of Thermodynamics & Heat Transfer, chapter 7, asked 2× - [Sphere through circle of two spheres, centre on a plane](https://www.bctengineer.com/question.md?key=semester_2%2Fmathematics%3Asphere-through-circle-two-spheres) — Mathematics, chapter 3 - [Short note: Two magic tees connected in H-plane](https://www.bctengineer.com/question.md?key=semester_7%2Frf_and_microwave_engineering%3Atwo-magic-tees-h-plane-note) — RF and Microwave Engineering, chapter 4 - [Two-bar plane truss displacement and member forces](https://www.bctengineer.com/question.md?key=semester_8%2Ffinite_element_method%3Atwo-bar-truss-member-forces) — Finite Element Method, chapter 3