Study and Use of Prismatic Compass survey
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- čas přidán 9. 03. 2021
- See how for an area coverd by three stations, the station are marked and bearings are measured so that triangulation can be marked with respect to these three lines AB, BC and CA.
One cannot overstate the importance of taking the back bearing. My experience with compass work, decades ago, showed me how many times there appeared a "local attraction" which pulls the needle away from the proper heading. If one excludes the back bearing they become unaware of how far off they have become on the line to be surveyed. In the early 1980's I would use a compass to "rough traverse" the survey for new underground gas lines. We would use aerial photo's to map the proposed route, then place "targets" at road crossings and intersections to "reinforce" the course. I would go out with my compass and flag a line between these targets. Sometimes I was pretty close, most times I would have to back track and correct my error. Then the survey crew would come through with total stations and run the "true line". Now GPS has changed all of that, but it was a fun exercise and a real eye opener on the limitations of compass accuracy. Later I would have the crews rough tape the surveyed line, after it had been cleared to get from one reference point to the next. This to was a good exercise as the crews got a "real" lesson of how inaccurate many of the original surveys were. When we did boundary work this lesson helped them to understand that one had to look in a bigger circle than a layman might of expected to find the called for corner. As technology has progressed the accuracy of surveying has greatly multiplied. Accurate geospatial location is the basis for civil progress in land development. Many countries are way behind on the importance of this, as a result conflicts with roads, drainage, utilities, and buildings occur simply because there is no information base to prevent it. Governments would be advised to use GPS to place suitable controls so that private firms, even using a compass and tape could survey and plan for infrastructure that works together. Great video guys, how about one where you head out of the park!
Dear sir Thank you for your reply. And yes correctly said Back bearing is must to have accuracy
Agree with Bell sir
Yes from each station Back bearing needs to be taken first then the Fore bearing, always....
Also then from initial station the bearing observed.....
Thank you sir for good explanation
Really great effort sir
Thank you Sir 💯
Useful Vdo, thank you sir
Thanks soo much much sir♥️♥️
Vedio helps a lot thanks. Sir. ❤
Thankyou for the video
Helpful video Sir
Thanku sir 🙏🙏
Nice vdo sir
Very useful video ❤
Thanks sir
Super sir Thank you sir 😄
Awesome❤
Thanks
What is compass
New subscriber
Helpful
Good 👍
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Thank for good explanation Sir..
Good
Nice video
Sir are these the corrected fore bearing and back bearing of line AB,BC And CA???
Please reply sir ASAP
No
These are observed FB n BB
Are to be corrected by included angle method or local attraction method
320th subscriber
Sir ji thoda hindi me bhi bola kro tb jyada ache smjh aayega 😅 because hindi humari matra bhasa hai
Please hindi language use sir
💯💯70000000000
Are hindi hi bol le te sir kyu hindi Bolne me sharam Aati h kya
Hi, being in Maharashtra and teaching them, so was in Marathi, here after I wl do it in Hindi.....ok