INSTRUMENTS : 1) Plane table 2) Through Compass 3) Spirit Level 4) Plumb bob with plumbing level 5)Alidade PROCEDURE: Choose an auxillary point Set the table at such that approximately ‘D’ near ‘C’. ‘D’ ‘ab’ parallel to AB. Keep the alidade at and and draw a resector. Draw resection from by ‘a’ sight ‘A’ ‘b’ sighting to intersect the previous line the to the ground and drive ‘B’ at‘d’. Transfer point‘d’ a peg. Keep the alidade and sight and draw a ray or line. Mark a point c1 on the line to at‘d’ ‘c’ represent the distance ‘DC’. Shift the table to C, orient the table by taking back sight to and centre it with reference ‘D’ to c1. Keep the alidade pivoted at and sight it to A. Draw a ray to intersect the previously dawn ‘a’ ray from in ‘D’ ‘C’. Pivoting the alidade about and sight Draw a ray to intersect the ray drawn from ‘C’ ‘B’. ‘D’ to at ‘B’ ‘b’. In order that ab and to coincide keep a pole in the line at a great distance. ‘ab’ ‘p’ ‘ab’ Keeping the alidade along rotate the table till is bisected clamp the table. ‘ab’ ‘p’ After orientation draw a resection from to and another from to The ‘a’ ‘A’ ‘b’ ‘B’. intersection of which will give the position by the plane table. ‘c’ occupied RESULT: Thus the position of station occupied by the plane table is determined. Ex. No: 9 PLANE TABLE SURVEYING THREE POINT PROBLEM USING – BESSEL’S GRAPHICAL SOLUTION Surveyor : Date / Time :
INSTRUMENTS : 1) Plane table 2) Through Compass 3) Spirit Level 4) Plumb bob with plumbing level 5)Alidade PROCEDURE: Choose an auxillary point ‘D’ near ‘C’. Set the table at ‘D’ such that ‘ab’ approximately parallel to AB. Keep the alidade at ‘a’ and sight ‘A’ and draw a resector. Draw resection from ‘b’ by sighting ‘B’ to intersect the previous line at‘d’. Transfer the point‘d’ to the ground and drive a peg. Keep the alidade at‘d’ and sight ‘c’ and draw a ray or line. Mark a point c1 on the line to represent the distance ‘DC’. Shift the table to C, orient the table by taking back sight to ‘D’ and centre it with reference to c1. Keep the alidade pivoted at ‘a’ and sight it to A. Draw a ray to intersect the previously dawn ray from ‘D’ in ‘C’. Pivoting the alidade about ‘C’ and sight ‘B’. Draw a ray to intersect the ray drawn from ‘D’ to ‘B’ at ‘b’. In order that ab and ‘ab’ to coincide keep a pole ‘p’ in the line ‘ab’ at a great distance. Keeping the alidade along ‘ab’ rotate the table till ‘p’ is bisected clamp the table. After orientation draw a resection from ‘a’ to ‘A’ and another from ‘b’ to ‘B’. The intersection of which will give the position ‘c’ occupied by the plane table. RESULT: Thus the position of station occupied by the plane table is determined. Ex. No: 9 PLANE TABLE SURVEYING – THREE POINT PROBLEM USING BESSEL’S GRAPHICAL SOLUTION Surveyor : Date / Time :
survey_lab_manual_r2013_-_venkat.docx