. Handbook of the Southern Nigeria Survey and text book of topographical surveying in tropical Africa. ew. V. Read the forward angle on both verniers (F, F).VI. Take the mean (M).VII. Subtract M from M and get the included angle (A).VIII. Read the vertical angle to the forward station and bubble(V). IX. Reverse the telescope, unclamp both the plates, set thevernier at about 35, clamp top plate, intersect back station roughlyand clamp bottom plate. Intersect the back station accurateh,face left. X. Read the back angle on both verniers (b, b).XI. Take the mean (m).XII. Unclamp top plate and swin
. Handbook of the Southern Nigeria Survey and text book of topographical surveying in tropical Africa. ew. V. Read the forward angle on both verniers (F, F).VI. Take the mean (M).VII. Subtract M from M and get the included angle (A).VIII. Read the vertical angle to the forward station and bubble(V). IX. Reverse the telescope, unclamp both the plates, set thevernier at about 35, clamp top plate, intersect back station roughlyand clamp bottom plate. Intersect the back station accurateh,face left. X. Read the back angle on both verniers (b, b).XI. Take the mean (m).XII. Unclamp top plate and swing left on to forward top plate and intersect with slow-motion screw. XIII. Read the forward angle on both verniers (f, f). XIV. Take the mean (m). XV. Subtract m from m and get the included angle (a).XVI. A and a should agree by about 10 with a good observerand good instrument. If they differ by more than 20 a third round 167 128 SPECIMEN PAGE ANGLE BOOK Gold Coast Method(For explanation see para. 167) { F. L. S. L.) ( ) (y) 0 48 179 II 10 )20 ( 3034- 354- 4-5 £ =70=5 E 60-6. The letters in brackets are explanatory onlyThe bearing o|f the leg 28 to 29 is supposedto be 8 0 10. 167-169 129 of angles must be taken, as in I. to VIII., with the vernier set atabout loo^ XVII. The mean of A and a (or the mean of A, a, and any otherround) is taken as the included angle (c) and is entered on theleft of the station, as shown in the field book. XVIII. The included angle is then applied to the bearing of thelast leg and is entered on the right of the station (d). This is the false bearing of 29 to 30, as mentioned in para. 161, 4th process. XIX. Check the false bearing for gross errors b)- the Read the vertical angle on the forward station and the bubble (v). (b) It will be noticed that the vertical angle to the front stationonly is read, and this after the horizontal angle has been dealtwith. The observer intersects a sight-vane adjusted to the heightof
Size: 1814px × 1377px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidhandbookofso, bookyear1911
