I am trying to draw a legal description in autoCAD 2013, i have formatted my drawing units to surveryos units and i was going along just fine until i got to a curve.  How do i continue my drawing and add the curve? this is what I am given: "Thence along a curve to the right having a central angle of 19'21'33. A radius of 694.26 feet. An arc length of of 234.58 feet and a chord that bears north 35d29'19"" I dont know what to do with that information so that it will draw it the correct arc.....PLEASE HELP
jbaylie2013-03-29 01:14:50

That's a typical horizontal curve which anyone familiar with basic math should know how to construct.  You have all the information you need (angle and radius) plus some extra (arc length and chord).  Try an Internet search for "horizontal curve" and you'll see how one is constructed.  Remember that your radius has to be perpendicular to the property lines on either side of the curve.

did not say it was hard, i sadi i was stuck. I looked it up on the internet and got here, i figured this was the place but i guess not.

uploads/175428/CURVE01_A.dwg
Hello John, please tell me ( us ) if it's ok because it's also not too much easy for me ( including the barrier of the language and units of course ).

Draw a circle with the given radius.Draw a line from the center of the circle to the easterly quadrant of the circle.Draw a second line using the direct distance entry method (at the command line) as follows...@694.26'<19d21'33"Trim the circle leaving the arc between the two lines you drew intact.  That's your curve.  Now go do it for your property map.

The last line you drew prior to the curve should be tangent to the curve (or description would have said "non-tangent").  Offset this line to the right, a distance equal to the curve radius. The end of the offset line will be the center of the curve. Draw a line between those endpoints, rotate that line by the central angle, this will set the end of the curve.  Draw a circle and trim to get desired curve.

Ok John and CarlB for the central angle of 19d21'33, radius of 694.26 giving an arc of 234.58 feet but where is the chord bearing north 35d29'19" ?
Please take a look at my uploaded drawing CURVE01_A.dwg for me ( us ) understanding better ( or understanding at all ).

uploads/353260/ArcLength.lsp

Try out the attached ArcLength.lsp with its ARCL command [a new .LSP version I just made of what I've had as a screen menu item for many years] -- a way to draw an Arc including specifying the LENGTH ALONG THE CURVE [an aspect you can't use in AutoCAD's ways of drawing Arcs, unless that's been changed in a newer version than mine].  It was designed for property-description Arcs like your example.  It asks for the start point [defaulting to the last point, usually of a preceding Line but including getting it right for a preceding Arc if that was drawn with this command], starting direction [defaulting to tangent continuation as is so often the case in property boundaries], radius, length along the Arc, and whether it curves left or right.
At this point that's the only variety of Arc it draws, but I may work on a version, or an option in this, to specify by length and direction of chord.

The chord is the straight line from beginning to end of the curve. You have it in your drawing. if you change units to "survey" and list the line, it reads: LINE      Layer: "0"                            Space: Model space                   Handle = 12e86              from point, X=68'-6.90566369"  Y=63'-1.85544090"  Z=0'-0.00000000"                to point, X=57'-3.37070543"  Y=47'-3.76252329"  Z=0'-0.00000000"          Length =19'-5.46314963",  Angle in XY Plane = S 35d29'19.0000" W A line with bearing SxxxxW is same as one of NxxxxE (just reversed endpoints).  The original poster neglected to specify a "W" or "E" at the end of the chord bearing.  

Hello CarlB, thanks again for your explanations ( I know what is a chord, an arc, an arrow ).
I just wanted to know if the drawing was in the good direction towards the north with the OP informations :
A curve to the RIGHT ............a chord that bears north 35d29'19".
I have AutoCAD Mechanical 2012 and when I use the command UNITS I get the palette that you can see in my drawing ( unité de dessin ) and I don't have "survey" but :
Architecture, Décimal, Fractionnaire, Ingénierie ( that I choose ) and Scientifique ( It's written in my AutoCAD french release but I'm sure that you can understand it very well ).
 
Can you update my drawing with the right units setings, rotate the chord to the right angle towards the north and upload it again ?
 
By the way we don't have any news from jbaylie, have you done your drawing allright ?
 

CarlB, i'm coming back on my answer. it's true that my sentence was not right.
Instead of "what about the chord" I wrote "where is the chord" and this leaded to this confusion.
I apologize for this.

Bonjour Phillipe, You have drawn the arc and chord correctly, for a chord that bears to the northeast. jybaylie provided incomplete information on the chord bearing, we don't really know if bearing was to northwest or northeast since chord bearing didn't have a "W" or "E" at the end of the bearing.Whether a curve is to the "right" or "left" is relative to the line bearing prior to the curve, that also wasn't provided. As to your units question, change the "angle type" (ddunits - Unites de dessin) to Surveyor (arpenteur?), then listing of lines will show bearings/angles with cardinal directions. Carl  should have read

CarlB, thanks again for all, I changed the angles units to : Unités géodésiques and I had the information on the angle inside the informations of the LIST :  Angle dans le plan XY = S 35d29'19.0000".
I had to choose between : Deg/Min/Sec , Degrés décimaux , Grades , Radians , Unités géodésiques.
It looks that I have the good information.
Maybe some dayjbaylie will give us the information about the correctness of all this.
 
I'm interrested in this because of the basic design, the topografic informations, the units that are different from what I see every day although beeing in an erection company that builts penstocks we regularly face civil engineering working with absolute coordinates in site works nd we have to provide them correct absolute coordinates.
 
CrlB, thanks again for the time waisted for me ( us ).

We know it's a curve to the right.  What we don't know (yet, the OP might still be able to provide it) is the bearing of line into the PC.  We know the Radius and the Central Angle (Delta).  That's all we need.  The bearing of the Chord is (in this case) equal to the bearing of the line to the PC - Delta/2.  Now it's simply a matter of drawing the lead line, a perpendicular line with the Radius to the centerpoint, and a circle.  The PT (point of tangency) will be the intersection of the circle and the chord line.Dave.

I looked at this again... you can compute the bearing of the line into the PC using the bearing of the Chord (given).Learning the relationships of a horizontal curve are important.  With a little simple trigonometry everything can be worked out as long as you know two items.  Here, the key items are the Radius and Delta (central angle).  From there it's a simple matter.  But having a good calculator handy helps!  I had to do most of this with paper and pencil here tonite!  Dave.uploads/35918/curve.dwg


heinsite2013-04-04 09:44:08