Drawing using suveyors' bearings

[Grizzly Albert]

Eldon, I'm sure you are right and I can change the clockwise direction easily. Could you please tell me how to get the direction back the way it was?

[ReMark]

Command: _line Specify first point:

Specify next point or [undo]: @27.09'

 

LINE Layer: "0"

Space: Model space

Handle = 3127

from point, X=285'-10.2021" Y=446'-11.4074" Z=0'-0.0000"

to point, X=312'-0.7777" Y=440'-1.4367" Z=0'-0.0000"

Length =27'-1.0800", Angle in XY Plane = N 31d36'0" W

Delta X =26'-2.5756", Delta Y = -6'-9.9707", Delta Z

=0'-0.0000"

[Tyke]

Are we getting bearings and azimuths all mixed up here?

When zero degrees is north then a bearing of N30°E has an azimuth of 30°.

When a bearing is N30°W it has an azimuth of 330°, a bearing of S30°E has an azimuth of 150°, a bearing of S30W has an azimuth of 210° and so on.

 

But as Mark so clearly said if you set your angular units to Surveyor's Units then AutoCAD understands the input and deals with it accordingly.

 

What's the system variables settings for DYNPICOORDS and DYNMODE: DYNPICOORDS should be set to 0 to allow polar input, check express tools to get all the settings for DYNMODE.

[ReMark]

I just wanted to point out with my previous post that AutoCAD will accept surveyor's units as input at the command line. The results of that method I have no direct control over. The user's mileage may vary. Caveat emptor.

[eldon]

Eldon, I'm sure you are right and I can change the clockwise direction easily. Could you please tell me how to get the direction back the way it was?

 

As i have an earlier version of AutoCAD. I don't know the exact way for you. But in my version I go to 'Format' then Units then Direction, and set it to East.

 

If you want to be brave and set some System variables, then at the Command line, type ANGDIR and set it to 0, and type ANGBASE and set it to 0. Now Surveyor angle input will work as you expect it to, BUT Azimuth angles will not be aligned.

 

When I first started, I had bright ideas about resetting the angles to agree with how I was working, but soon came to the conclusion that better left alone. For example, if you set North as the zero angle, then all text that you used to have at 0 degrees, now had to be at 90 degrees. Understand the system as it defaults, and work with it.

[eldon]

Are we getting bearings and azimuths all mixed up here?

 

As someone who has to use a foreign language programme, I am sure to be mixed up with my terminology. Here we call them Whole Circle Bearings which is the clockwise angle from North. We have no truck with those quaint quarter circle systems.

[Grizzly Albert]

You hit it, Eldon!

I had changed direction using angdir and angbase and couldn't find them again.

Thanks to everyone for your help, sorry to take up so much of your time.

[ReMark]

Does this mean we can all go for a beer and swap tall tales? Sign me up!

[Tyke]

and I'll have one too.

[Grizzly Albert]

Eldon,

Surveyors use the old "quarter circle" system these angles are, I believe, called bearings. I find it confusing but the chance for error increases geometrically when you try to convert each bearing to an azmuth.

 

When you're out in the field, azimuths are same as a compass-neat. Especially here in south Alabama where the declination is nearly zero.

[eldon]

Then I was not too far out with my technical terms, although for me, Azimuths are something to do with spherical and astronomical geometry.

 

Please don't confuse me with any more facts.

[ReMark]

Eldon: Maybe you were thinking of Issac Azimuth? Excuse me...Asimov.

[eldon]

Eldon: Maybe you were thinking of Issac Azimuth? Excuse me...Asimov.

 

I am not sure, now that you come to mention it. Something to do with arcs of a celestial great circle??

[Grizzly Albert]

Drinks on me. Come to Mobile or my home in Dauphin Island, Alabamastan.

[BIGAL]

Hey Grizzly this is what you want its shorthand verison of enter brg sideshot new etc its old code would do different now forget the @ and

ddd.mmss

 

 
(defun c:BRG ()
(setq pt1 (getpoint "\nPick start point'))
(setq dist (Getreal "\nenter distance"))

 (setq ang_ans (getstring "\nEnter bearing angle in Deg.MMSS :")) ; old code here would use dimzin now

 (setq ans_len (strlen ang_ans))
 (setq x 0)
 (while (/= char_found ".")
   (setq x (+ x 1))
   (setq ans_deg (strcat ans_deg char_found))
   (setq char_found (substr ang_ans x 1))
   (if (= x 9)(setq char_found "."))
  )
  (setq x (+ x 1))
  (setq ans_min (substr ang_ans x 2))
  (setq x (+ x 2))
  (setq ans_secs (substr ang_ans x 2))
      
   (if (= ans_min "")(setq ans_min "0"))
   (if (= ans_secs "")(setq ans_secs "0"))
   (setq ang (dtr (+ (atof ans_deg)(/ (atof ans_min) 60.0)(/ (atof ans_secs) 3600.0))))    
(setq pt2 (polar pt1 ang dist))
(Command "line" pt1 pt2 "")
)

[Grizzly Albert]

Thanks, Big Al, but, since I finally fixed it, I'm not going to fool with it again.

 

"A computer lets you make more mistakes faster than any invention in human history... with the possible exceptions of handguns and tequila."

Mitch Ratliffe