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ray_smith's_student
Posts: 2
Joined: 9/14/2009
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Help!? |
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Hey everyone,
I have surveying in my college course and I am having trouble with some homework problems. I was wondering if anyone knew how to find the answers for these kinds of problems?:
#1. The bearing of line CD is S45(degrees)20(minutes)40(seconds). What is the azimuth of line CD?
#2. The azimuth of line LM is 25(degrees)20(seconds). What is the back bearing of line LM.
Please tell me how to find the answers rather than giving them to me.
Thanks in advance
Cheers
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Tuesday, September 15, 2009 at 9:16:33 AM |
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jwahl
Posts: 8
Joined: 1/31/2009
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Re: Help!? |
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Azimuths are usually the angle from north clockwise in the range of from 0 to 360 degrees. Thus for example south is 180 degrees azimuth.
Bearings are usually given as angles in quadrants from the first named direction (North or South) towards the second named direction (East or West) so bearings in the SE and NW quadrants are counter clockwise from South or North and bearings in the NE and SW quadrants are clockwise from the first given direction.
So draw yourself a picture and it usually becomes more obvious what you need to do.
For example S. 73 degrees W. would be clockwise from south 73 degrees or 180 degrees azimuth plus 73 degrees which equals 253 degrees.
A bearing of N. 20 degrees W. would be counter clockwise from North or 360 degrees minus 20 degrees or 340 degrees azimuth.
To go the other direction from Azimuth to bearing you need to get that picture in your head of 90 degrees azimuth being east, 180 being south, 270 degrees being west and both zero and 360 degrees being north.
So an azimuth of between 90 and 180 is SE, between 180 and 270 is SW and between 270 and 360 is NW.
An azimuth of 136 degrees can first be categorized as being SE. So you can figure 180 degrees azimuth (south) minus 136 (counter clockwise angle from south) which gives you
S. 44 degrees E.
- jlw
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