AZDuffman
Joined: Nov 2, 2009
• Posts: 12333
December 19th, 2013 at 7:57:43 AM permalink
I know there must be a simple answer to this but cannot quite figure it out so I need some "math help" on it.

I am reading deed calls which are in direction and degrees. For example, say a call says "North 31 degrees 20 minutes West 300 feet." What I need to do is reverse the call so I get the same angle but going the other direction. IOW I need to know what I would tell a surveyor to go Sxx.xxE to get a line of the exact same angle and length.

Thank in advance if you can help.
All animals are equal, but some are more equal than others
ChesterDog
Joined: Jul 26, 2010
• Posts: 951
December 19th, 2013 at 8:15:03 AM permalink
"North 31 degrees 20 minutes West" is an angle of 31 degrees 20 minutes counterclockwise from north. The reverse direction would be an angle 31 degrees 20 minutes counterclockwise from south, which is "South 31 degrees 20 minutes East."

(Warning: I have no experience with surverying.)
odiousgambit
Joined: Nov 9, 2009
• Posts: 8465
December 19th, 2013 at 9:16:39 AM permalink
there is something to say for skipping the directional indication by 'words' and just use all 360 degrees in the first place. Then, to go opposite is to subtract or add 180 degrees.

360 degrees = 359 degrees 60 minutes

359 degrees 60 minutes minus 31 degrees 20 minutes = 328 degrees 40 minutes.

328.40-180=148.40 [minutes not decimals]

"South 31 degrees 20 minutes East." = 179.60-31.20=148.40 [minutes not decimals]

it checks. Two ways to get the same answer.

PS: I was relieved to see that this was not Teddy in a panic.
the next time Dame Fortune toys with your heart, your soul and your wallet, raise your glass and praise her thus: “Thanks for nothing, you cold-hearted, evil, damnable, nefarious, low-life, malicious monster from Hell!” She is, after all, stone deaf. ... Arnold Snyder
FleaStiff
Joined: Oct 19, 2009
• Posts: 14484
December 19th, 2013 at 9:30:21 AM permalink
Quote: ChesterDog

"North 31 degrees 20 minutes West" is an angle of 31 degrees 20 minutes counterclockwise from north. The reverse direction would be an angle 31 degrees 20 minutes counterclockwise from south, which is "South 31 degrees 20 minutes East."

(Warning: I have no experience with surverying.)

Look folks, y'all know I don't know nuttin' 'bout no reciprocal courses but I sure think the above is incorrect. You want a course that is 180 degrees from your given course.

Lets just do it from North 31 degrees West.. that is a course of (360-31)= 329 degrees. If you want the reciprocal its less 180 or 149 degrees.
dwheatley
Joined: Nov 16, 2009
• Posts: 1246
December 19th, 2013 at 11:08:28 AM permalink
Quote: ChesterDog

"North 31 degrees 20 minutes West" is an angle of 31 degrees 20 minutes counterclockwise from north. The reverse direction would be an angle 31 degrees 20 minutes counterclockwise from south, which is "South 31 degrees 20 minutes East."

(Warning: I have no experience with surverying.)

I was also going to post this but it seemed too easy. I think I agree.
Wisdom is the quality that keeps you out of situations where you would otherwise need it
AZDuffman
Joined: Nov 2, 2009
• Posts: 12333
December 19th, 2013 at 11:25:03 AM permalink
This is helpful but there still has to be a formula for this entry. Here is the issue in more detail:

1. Deed calls are always N or S xx E or W. For example, N90E is a dead east line, N0E is a dead north line.

2. If you need more than said 90 degrees you simply go the other direction. For example, you would never go N91E but instead would (should) go s1E.

3. Surveyors can go clockwise or counterclockwise at will. This is my problem. If I have an angle going clockwise my plotter cannot take another from another guy who went counter-clockwise.

Since few here survey or work with this stuff let me put it another way for you to chew on and maybe come up with the simple formula.

You and I are a distance apart. Picture a right triangle. If you walk 70 feet to your left, then turn rignt and walk 120 feet you will be at my spot. Now, how would you calculate the angles in "deed calls" for you to walk to me and me to walk to you? And what do I do to get the recipricol on any given deed call?

I know this must be simple but cannot quite figure the trick.
All animals are equal, but some are more equal than others
beachbumbabs
Joined: May 21, 2013
• Posts: 14232
December 19th, 2013 at 2:27:27 PM permalink
Draw 2 axes: n/s and e/w. you are working with reciprocal quadrants, so in 90 degree increments. minutes subtract from 60 for the recip. if one direction is S1E, its opposite is N89W. If one direction is N3degrees 20 minutesW, its opposite is S86 40 minutes E. All the numbers add up to 90. You're counting down from North, always. You re-start the count at the EW axis.
If the House lost every hand, they wouldn't deal the game.
ChesterDog
Joined: Jul 26, 2010
• Posts: 951
December 19th, 2013 at 3:24:20 PM permalink
Quote: AZDuffman

...You and I are a distance apart. Picture a right triangle. If you walk 70 feet to your left, then turn rignt and walk 120 feet you will be at my spot. Now, how would you calculate the angles in "deed calls" for you to walk to me and me to walk to you? And what do I do to get the recipricol on any given deed call?...

If I am facing north and turn to my left to walk 70 feet west and then turn to my right to walk 120 feet north to reach your position, our position is at a bearing of this angle west of north from my original location: arctangent(70/120) = 0.528074 radians = 30.2564 degrees = 30 degrees 15 minutes 23.17 seconds. And the bearing of my original position from our position is south 30 degrees 15 minutes 23.17 seconds east.

In Excel, use this formula if x is the east-west distance and y is the north-south distance: =180*atan(x/y)/pi()

This angle A is in degrees, and to convert to degrees minutes and seconds, do D = int(A); M = int(60*(A-D)); S = (A-D-M/60)*3600

And the Excel formula for the distance between our positions is: =sqrt(x*x+y*y). For this example, the distance is 138.9244 feet.

(Edit: these formulas only work for a flat earth or for relatively small distances on a real earth.)
teddys
Joined: Nov 14, 2009
• Posts: 5444
December 21st, 2013 at 8:09:07 PM permalink
Looks interesting! Looking forward to doing your job in a few weeks :)
"Dice, verily, are armed with goads and driving-hooks, deceiving and tormenting, causing grievous woe." -Rig Veda 10.34.4
AZDuffman
Joined: Nov 2, 2009