My best client has asked for help on a project they are buying. Commercial site, platted last year. The surveyor found the centerline monuments, which include non-tangent curves. There are only the usual three curve elements (delta, radius, arc). He found or set the right-of-way monuments, which include non-tangent curves. There are only the usual three curve elements (delta, radius, arc). The right-of-way width varies considerably, necking down as you head northward. There are no ties from the centerline to the right-of-way line.
The BOR has disciplined engineers and surveyor repeatedly for this. The last one, a month ago, resulted in a one-year suspension. One would think our peers would get the message: If nobody else can compute it, then it isn't good enough!
Rant off, but I'm still irked.
Sad evidence that it's too easy to become a PLS. No professional board should have to be chasing down minutiae like this, and no regulation should codify it. More stringent education and testing requirements can weed at least some of this out.
A few months ago a description came across my desk that was written by a local surveyor in 1984.
There were three curves along the highway boundary and he did not include a chord bearing and distance for any of them and the curve takeoffs were non tangent.
I did find the monuments he set and they were from within a tenth on less than 50ft calls to several feet different from his calls of over 500ft and he did have an EDM at the time.
They irk me too.
Just because someone doesn't do something doesn't mean they can't (or couldn't at one time). There are many capable Surveyors that pull the same crap. We already require a 4 year degree. Making it 8 want turn unethical dirt bags into legitimate professionals.
I just picked up my 3rd license. Trust me it was not easy. We need to demand better conduct and enforce the rule to practice within your expertise.
My 02 Tom..
I call them broken-backed curves. Non tangent curves, are hard to offset, (Some are real hard!)
I recommend that continuing education address this.
I always publish D-R-L-Chord brg dist.
But, non tangent curves, have their own pile of problems!
N
Bruce,
I recall in the 1980's the Arizona DOT wanted very few (maybe two)curve elements in their legal descriptions. Their belief was, the more curve elements you included the legal the bigger chance for a typo or miscalculation.
Go figure.
A lot of guys don't like needless numbers or redundancies in their descriptions or on their plats. I have found that the redundant values help me find an error when there is a busted number or typo. Of course I detest it even more when there isn't even enough to figure it out.
I'm not sure why a non-tangent curve is hard to offset. The problem is in laying out the non-tangent curve. I always identify them as non-tangent and include the bearing to the radius. And like you I publish the Radius, Delta, Length and Chord. I have had some jurisdictions require the radial even for tangent curves and ask what the Chord was (only in S CA). Of course the RR I was working for had just threatened the County
with federal lawsuits over holding up a project so I'm guessing they were taking it out on me.
> I have found that the redundant values help me find an error when there is a busted number or typo.
I believe it was "Nearly Normal" on the old board who once wrote that redundancy is ignorance in reverse.
Chord Brg, Chord, Radius & Arc
Gives anyone anything they need and it doesn't matter if the curve is tangent or not. Why do some people always try to make simple hard?
Chord Brg, Chord, Radius & Arc
Radius, arc length and radial bearings from PC and PT work for me..
"I'm not sure why a non-tangent curve is hard to offset."
Because the offset curve and the offset tangent line endpoints fall in different locations - but probably very close together, perhaps on the same monument, which would make them difficult to identify.
"... the bearing to the radius."
It is correct to publish the radial bearing, which is the bearing FROM the radius...
> ... There are only the usual three curve elements (delta, radius, arc)....
In each of the 3 states I'm registered in the required curve elements are specified in the statutes. It's not a matter of personal preference.
The radial bearing thing works fine. In fact that is what is required in British Columbia. It is actually easier to annotate on a map. But OR, WA, and OK law requires that chord bearings and distances be given.
> Because the offset curve and the offset tangent line endpoints fall in different locations
The intersection of the two is easy to identify, and is the logical way of offsetting a non-tangent curve. It's the way AutoCAD does it.
Local practice is Radius and Arc length, unless it's a non-tangent then we label the radial bearings. Our Statutes don't specify particular drafting requirements. It's assumed that as professionals we know what's necessary.
I think the reliance on cad is a big factor in this problem. "Just click on it", mentality. Oregon requires chord bearing and chord distance along with radius, length and delta on plats. I like the idea of chord bearing and chord distance because you can always compute the curve along with radius and legnth, but it does result in a lot of broken back curves because one does not have to be so cautious about computing concentric curves, where as in California we typically computed through the radius with radial bearings where needed, which was ok until someone busted the radial. My 2 cents, Jp
Statutes are ...
MINIMUM standards. There's no harm in giving more info!
> Our Statutes don't specify particular drafting requirements. It's assumed that as professionals we know what's necessary.
BINGO! If physicians in a certain jurisdiction consistently butchered people, we wouldn't say, "Wow, our education and licensure programs are fine, we just need to codify suture technique and stay on top of these guys." No, we'd fix the education and licensure requirements!
I don't think it is requited in WA. I think just R,D,L. But I could be wrong.
Chord Bearings are the WORST data to put on any map. I know it is required in a lot of states but chord bearings are the cause for a lot of non-tangent curves. I show them only when required. Usually a radial bearing (and yes a radial bearing is FROM the radius point.)
The majority of the offenders I have witnessed are educated and properly licensed individuals that have the attitude that their way is correct and to he** with minimum standards. IMHO, the problem is the enforcement of the rules and standards, not the licensure criteria. Enforce what is in existence, don't create more hardships for the hard working individuals that are qualified and have the aptitude for the profession because some person with an "I'm better that you" attitude refuses to comply with the program.
Rant off!