1 / 26

BASICS OF TRAVERSING

H.U. MINING ENGINEERING DEPARTMENT MAD 256 – SURVEYING. BASICS OF TRAVERSING. A closed traverse. A traverse between known points. What is a traverse?. A polygon of 2D (or 3D) vectors

Gabriel
Download Presentation

BASICS OF TRAVERSING

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. H.U. MINING ENGINEERING DEPARTMENT MAD 256 – SURVEYING BASICS OF TRAVERSING

  2. A closed traverse A traverse between known points What is a traverse? • A polygon of 2D (or 3D) vectors • Sides are expressed as either polar coordinates (,d) or as rectangular coordinate differences (E,N) • A traverse must either close on itself • Or be measured between points with known rectangular coordinates

  3. (E,N)known (E,N)known (,d) (,d) (,d) Applications of traversing • Establishing coordinates for new points (E,N)new (E,N)new

  4. (E,N)known (E,N)new (E,N)known (E,N)new (E,N)new (,d) (,d) (,d) (,d) (,d) (,d) (E,N)new (E,N)new Applications of traversing • These new points can then be used as a framework for mapping existing features

  5. (E,N)known (E,N)known (E,N)new (E,N)new Applications of traversing • They can also be used as a basis for setting out new work

  6. Equipment • Traversing requires : • An instrument to measure angles (theodolite) or bearings (magnetic compass) • An instrument to measure distances (EDM or tape)

  7. Measurement sequence C 232o 168o 60.63 99.92 56o B 352o 205o D 232o 77.19 129.76 21o A 32.20 118o 303o 48o E

  8. Computation sequence • Calculate angular misclose • Adjust angular misclose • Calculate adjusted bearings • Reduce distances for slope etc… • Compute (E, N) for each traverse line • Calculate linear misclose • Calculate accuracy • Adjust linear misclose

  9. Calculate internal angles • At each point : • Measure foresight azimuth • Meaure backsight azimuth • Calculate internal angle (back-fore) • For example, at B : • Azimuth to C = 56o • Azimuth to A = 205o • Angle at B = 205o - 56o = 149o

  10. Calculate angular misclose

  11. Calculate adjusted angles

  12. Compute adjusted azimuths • Adopt a starting azimuth • Then, working clockwise around the traverse : • Calculate reverse azimuth to backsight (forward azimuth180o) • Subtract (clockwise) internal adjusted angle • Gives azimuth of foresight • For example (azimuth of line BC) • Adopt azimuth of AB 23o • Reverse azimuth BA (=23o+180o) 203o • Internal adjusted angle at B 150o • Forward azimuth BC (=203o-150o) 53o

  13. Compute adjusted azimuths C 53o B 150o D 203o A E

  14. Compute adjusted azimuths C 233o 65o 168o B D 23o A E

  15. Compute adjusted azimuths C 53o 348o B 121o D 23o 227o A E

  16. Compute adjusted azimuths C 53o 168o B D 23o 47o A 106o 301o E

  17. Compute adjusted azimuths C 53o 168o B D 23o 227o 98o A 121o E

  18. (E,N) for each line • The rectangular components for each line are computed from the polar coordinates (,d) • Note that these formulae apply regardless of the quadrant so long as whole circle bearings are used

  19. Vector components

  20. Linear misclose & accuracy • Convert the rectangular misclose components to polar coordinates • Accuracy is given by Beware of quadrant when calculating  using tan-1

  21. For the example… • Misclose (E, N) • (0.07, -0.05) • Convert to polar (,d) •  = -54.46o (2nd quadrant) = 125.53o • d = 0.09 m • Accuracy • 1:(399.70 / 0.09) = 1:4441

  22. Bowditch adjustment • The adjustment to the easting component of any traverse side is given by : Eadj = Emisc * side length/total perimeter • The adjustment to the northing component of any traverse side is given by : Nadj = Nmisc * side length/total perimeter

  23. The example… • East misclose 0.07 m • North misclose –0.05 m • Side AB 77.19 m • Side BC 99.92 m • Side CD 60.63 m • Side DE 129.76 m • Side EA 32.20 m • Total perimeter 399.70 m

  24. Vector components (pre-adjustment)

  25. The adjustment components

  26. Adjusted vector components

More Related