Curve description -- seemingly simple question

in my little world common practice would be tangent at the beginning of the curve.

Just say it as it is:

For tangential curves and tangents
- then tangentially along a curve with a radius of ___ and a central angle of ___
- then tangentially BEARING DISTANCE

If NOT tangent, then
- then non-tangentially along a curve with a radius of ___ and a central angle of ___
_ then non-tangentially BEARING DISTANCE

so, which tangent curve are we talking about?

Looking at Peter's sketch, a non tangent example: thence from a tangent bearing N85E, easterly and northeasterly along a curve to the left, having a radius of xxx feet, through a central angle of 23 degrees, xxx feet. For the curve impaired you could add "concave to the north" after "to the left".

I have seen the phrase "..on a curve to the left with a central point 90 degrees to a back tangent of (insert brg)...."

Never used it, but seen it.

I just give the curve Length, Arc Distance, Radius, Chord Bearing and Distance. What does tangent or non tangent add to the description?

...thence along the arc of a non-tangent curve to the left having a radius of XXXXX feet, an arc length of XXX.XX feet, a delta angle of XXdXX'XX" (chord bears N XXdXX'XX" E, XXX.XX') to a set 5/8" iron rod with a plastic cap marked CK Hines, PLS 1592;

I prefer to use a radial bearing to define a not-tangent curve rather than a chord bearing and distance. A chord distance rounded to the nearest hundredth can create a disagreement with the delta of the curve.

6. South 89å¡ 20' 54" East, 6.00 feet to a point of nontangent curvature on the westerly right of way line .......

7. 24.45 feet along the arc of a curve deflecting to the right, having a radius of 100.00 feet (chord: South 07å¡ 39' 18" West, 24.39 feet) to a point of tangency; thence

SPMPLS, post: 381658, member: 11785 wrote: I prefer to use a radial bearing to define a not-tangent curve rather than a chord bearing and distance. A chord distance rounded to the nearest hundredth can create a disagreement with the delta of the curve.

Is the delta of a curve required in some states in a description? I don't see what it brings to the description if Arc, Radius, Chord B&D is given. Of course if it was required, I would show the delta.

lmbrls, post: 381663, member: 6823 wrote: Is the delta of a curve required in some states in a description? I don't see what it brings to the description if Arc, Radius, Chord B&D is given. Of course if it was required, I would show the delta.

it brings precision... and that can matter

I am not aware of the requirement to include the delta, but the most common elements reported for a tangent curve are radius, delta, and length. I don't see why that wouldn't be the same for a non-tangent curve, with the addition of the radial bearing to define the orientation of the non-tangent curve. Using the radius, which is most often an absolute number, such as 400.00' (no rounding involved) and a radial bearing and delta to the nearest arc second reduces the amount of rounding error that could accumulate. It is a matter of precision.

Mathematically it is only a line that is tangent to a curve. There is no curve that is tangent to a line.

Whether a tangent or non-tangent curve, the addition of the "curve to left/right" call is essential and defines the direction of concavity. Adding a direction call such as "...a curve to the left, concave to the north..." is redundant and only creates the opportunity to introduce conflicting calls, IMO.

lmbrls, post: 381655, member: 6823 wrote: I just give the curve Length, Arc Distance, Radius, Chord Bearing and Distance. ...

Oregon law requires that those 5 elements be shown on plats. Perhaps for that reason it is common around here to include them all in descriptions.

[INDENT=1]... [Bearing], [Distance] to the beginning of a xx.xx foot radius curve to the right(left); THENCE along said curve xx.xx feet through a central angle of xxå¡ xx' xx" (the chord of said curve bears [Bearing], [Distance]); THENCE [Bearing], [Distance] ...[/INDENT]

Wattles states that tangency is assumed and it is only necessary to specify when a curve is non-tangent. That's how I roll.

That is how I roll too. It is tangent unless stated otherwise.

I agree with the need for central angles and accuracy. When done correctly, it can make a complicated description easy to compute. I have adopted the method described by Gurden H. Wattles in his text Writing Legal Descriptions, the one with the yellow cover and blue text. Here is a recent sample of some intersecting curves.

Ken

thence along said division line, North 42å¼ 02' 40" West 535.85 feet to the intersection of a 125.00 foot radius curve in the east right of way line of said [road], to which intersection a radial line bears North 23å¼ 38‰Ûª 00‰Û West;

thence northeasterly along the division line between said [road] and Lot 7, with the arc of said 125.00 foot curve, deflecting to the right through a central angle of 21å¼ 49' 50" an arc distance of 47.63 feet to the intersection of a 65.00 foot radius curve, to which intersection a radial line bears South 65å¼ 34‰Ûª 40‰Û West;

thence easterly, northerly and westerly along the division line between said [road] and Lot 7 and Lot 6 on said Map No. [xxxx], with the arc of said 65.00 foot curve, deflecting to the left through a central angle of 222å¼ 04' 36" an arc distance of 251.94 feet to the Point of Beginning.

I include delta in all calls, tangent or not, required or not (frankly haven't even looked into whether it is required, just always have taken for granted, i guess, that it's a necessary element to define a curve), and also have an additional subtle variation in language when approaching one in a call:

(tangent): "to the point of curvature of a curve to the left, having a radius of xxx.xx feet, a central angle of xxxx, etc."

(non-tangent): "to the beginning of a non-tangent curve to the left, having..."

It is tangent if the line is tangent to the curve. It is non-tangent if the line is non-tangent with the curve.

As for how to describe the boundary, we are supposed to be professionals - figure it out. If you can't figure it out, please stick to pounding hubs.
We certainly don't (or at least we shouldn't) need laws to tell us how to write descriptions.