A spiral is a curve of constantly varying radius. Here is how the Oregon DOT describes spirals - this example is from their Right of Way Engineering Manual, a good source for certain formats. Pretty simple.
. . . which center line is described as follows:
Beginning at Engineer's center line Station 1079+76.00, said station being
549.00 feet North and 723.28 feet East of the South quarter corner of Section 27,
Township 7 South, Range 11 West, W.M.; thence South 46° 59' 38" East
1,027.87 feet; thence on a spiral curve right (the long chord of which bears South
43° 51′ 22″ East 199.76 feet) 200.00 feet; thence on a 608.48 foot radius curve
right (the long chord of which bears South 30° 04′ 19″ East 158.97 feet) 159.42
feet; thence on a spiral curve right (the long chord of which bears South 1° 19′
41″ West 746.91 feet) 760.00 feet to Engineer's center line Station 1101+23.29
Back equals 1101+16.80 Ahead; thence South 13° 12′ 56″ West 119.42 feet to
Engineer's center line Station 1102+36.22.
@Norman_Oklahoma Nice, they totally ignore the elements of the spiral and just do the long chord. I would love to do that but I was concerned about creating a gap...
Since a spiral can’t be offset I’m curious how others would define the R/W, on US Surveys BLM would define with equally divided short chords. I’d considered, but didn’t get the opportunity to try defining a separate spiral for the sides of the R/W.
Carlson apparently has a routine to offset a spiral. Whether it works or not I don’t know, but I guess that would be my first solution.
I guess I should have said that there's no mathematical way to offset a spiral, to my knowledge anyway,
Civill3D and other programs that I've used can offset them, but the result is a polyline with a whole bunch of teeny-weeny segments.
"...they totally ignore the elements of the spiral and just do the long chord. "
Not ignoring. The bearing of the connecting tangents, the length, and the ending radius fully defines the spiral. The chord bearing and distance provide redundancy. That is (more than) all you need.
I guess I should have said that there’s no mathematical way to offset a spiral, to my knowledge anyway,
Civill3D and other programs that I’ve used can offset them, but the result is a polyline with a whole bunch of teeny-weeny segments.
Oh, I see.
Idaho roadways created by prescription can be limited to improvements or a set statutory width. The law here is not simple and few have bothered to read (much less understand) it. They simply echo the last incorrect width shown by a surveyor or asserted by a receptionist at the local highway department.
One of the Boise law offices maintains an excellent road handbook and posts it free online.
I did forget you mentioned that. Have you reviewed the grantor grantee indexes at the County? If there are state plans there were almost certainly deeds.
...or asserted by a receptionist at the local highway department.
Well, that's not a surveyor problem, imo. If I call the agency that is supposed to know and... they don't know then... 🤷♂️
One of the Boise law offices maintains an excellent road handbook and posts it free online.
Do you have a link to this handy? I'm not sure if I have this in my collection.
I did forget you mentioned that. Have you reviewed the grantor grantee indexes at the County? If there are state plans there were almost certainly deeds.
Not yet, but I did put in an order for a title report so we'll see if anything shows up there.
The link is about a paragraph long. Do a search for Givens Pursley Idaho road law handbook and it will pop up.
In the meantime a little food for thought...
We form professional opinions based on evidence evaluated under the law. Why is it acceptable to simply list the assertion of a person with no authority as our professional opinion of a right of way location? That is tantamount to asking the neighbor of our client where the boundary is and mapping it without question. The next surveyor then shows what we have on our map without research or question.
A right of way is a boundary and must be determined to the same standard of care as any other boundary line.
Why is it acceptable to simply list the assertion of a person with no authority as our professional opinion of a right of way location?
I'm not sure what you're referring to. Are you talking about a survey that perpetuates the right of way location from a previous survey?
If so then I would say presumably that previous surveyor, being the professional that the state says they are, did consult an authority and that's where the right of way location came from.
I find virtually no correct right of way determinations in some counties. Zero. When I contact the surveyor they either say it was shown that way by others or the road department gave the width. More often than not the creation documents and/or governing law are easily obtained.
Part of the purpose of the narrative law was to require us to obtain and cite source information for all boundaries shown on our surveys. Records of survey cannot create rights of way and are not a valid citation.
Well, if someone isn't doing enough research then that's a standard of care issue.
It's amusing how some of the entities responsible for knowing this stuff don't even want to answer the question.
I've called a county to inquire about a right of way only to be told to contact a city in the county instead. When I contacted the city they immediately tried to pawn me off on the county. I go BZZZZT I already talked to them and they told me to come to you. I don't care which, but one of these fools is going to give me the info I'm after !
I talked to another city about a right of way once where the guy literally told me he didn't want to give me an answer because there was too much liability involved. 🤦♂️🤦♂️
Therein lies part of the problem. The entity having jurisdiction is a matter of law. Many of those entities have no idea where the width is established and believe some manager can just declare it by fiat.
In the majority of cases a width can be easily determined with a little research. Where width is not set, the commission should make an assertion (with the advice of qualified counsel) and follow up with a road validation. If not challenged that width has certainty.
My greatest issue here is the impact of an incorrectly shown r-o-w. It can take rights from one and assign them to another, allow prohibited development, or disallow where it should be fine. These things hurt people and it is our paramount duty to prevent that. We need to put an end to survey by old wives tale and push for better practice. This old dinosaur will never stop preaching this while hammering the table..
We need to put an end to survey by old wives tale and push for better practice.
I don't think any surveyor is opposed to that, but when the authority doesn't know, or doesn't want to do their job, and regularly tries to pawn the decision-making off on us (pretty sure I've had an agency respond to my question with "well what do the plats/surveys say" too) then it doesn't exactly make our job any easier.
I certainly don't mind making a decision based on the fieldwork and research I've done, but in cases where that evidence isn't clear it's important to have authorities that don't give squirrelly answers.
