California Surveyors Forums

I have a CL I am trying to establish consisting of 2 curves reversed of each other with a section of straight tangent between them. I have found monuments at all four BC/EC curve points and defining the tangents into/out of this section of CL.

To resolve the CL, I can:

1) Hold the monument positions and the record radii. Then the curves/lines would be non-tangent.

2) Hold the tangent lines into/out of the curves, fillet them with record radii, and then the monuments would be called off.

3) Use the tangent bearings from the monuments to establish the curve deltas, use the distance between the monuments to define the chord length, and adjust the record radii for the curves to match the monuments with the points of tangents.

What would you do?

It's going to depend on what effect the sidelines of the right of way have on improvements - if any.

Option three is usually the best, provided that the radii don't change significantly.

I have encountered situations in which any of the three options were valid. A lot depends on the time frame that the original centerline was calculated, and the method in use. Follow in the footsteps. If the monuments were placed contemporaneously, they are going to have the greatest weight.

These problems are not generally capable of bright line solutions. That's why we get paid the medium bucks!

Warren,

Half has no improvements, the other half is improved with subdivisions (wall, CGW, & landscaping) and the effect would be minimal to the improvements with any of the 3 options.

The monuments were set with the County Survey establishing the road layout and at the same time period dedication deeds were recorded, but not cited in the dedication deeds.

What was the original intent? Usually intended to be tangent lines to a radius. Sometimes I will run record and rotate to the best monuments. Inverse to check the tolerance of all of the found monuments and is what I am comfortable with. Have found a lot of monuments are set 0.1-0.2'+/-

With option 3 I still can't make it hit all the monuments, I think I am leaning towards Option 1 at this point.

How far is "off"?

Medium bucks. Like that. ;)

I've been using the Record Tangent distances lately to establish PI's of the curves and then letting the radius distance float. If you're working in an area where the chord data is usually shown then that should work too. In So Cal the Tangent Distance is shown a lot of the time, but not always. I like holding tangent as much as possible, but sometimes you have to break the back and make it non-tangent.

The math is there to help the next guy find the monument, but the monument is the BC/EC or Property Corner.

What if you found the monuments on a curved property line where the deed description has a nice tangent curve with a 500' radius and then you hold the monuments at each end of the curve for line and fillet the record radius and the monuments are off by 0.3' or 0.4'? Are you going to call those monuments off and tell the property owner, "Well the monument is on line, but the beginning of the curve is 0.4' over there at an unmarked point on the ground?" I would feel much better letting the mathematical value of the radius float and hold the monuments as the actual BC or EC.

I would think you go with option 1 and slide the BC and EC on the tangent lines if the intent is for a tangent curve. I know on a lot of older county road maps they only used to set the PI's specifically for this reason.

hold the measured chord, hold the measured delta and break the radius. That is the best way to do it. Radial lines at the bc and ec will be within a second or two or three or perpendicular.

Flip somebody out and show on the map the radius of one curve is 200.09' vs 200.00 and the other is 350.14 instead of 350 radius. Or whatever the numbers are.

It seems that I've seen Solution No. 2 used most often in this area.

This does not mean that No. 1 and No. 3 are not viable solutions.

Since improvements are not in play here, I think that you should be guided by what else may have done in the immediate area and how your particular solution fits in that area.

........but what do I know?

4) Any combination of any or all of 1, 2, and 3 that best fits all of the monumentation of the centerline and sidelines of the road in the vicinity of the curves. As in other retracement situations, the monument locations as set are the highest consideration, whatever has to yield in the dimensions to hold the monuments to be on the centerline and as close to the ends of the curves as you can fit those curves to be is what you do. The exceptions being if any of the monuments had been moved from their original location or if any of the CL mons had been set with in an erroneous location and that error is made obvious in that the roadway was constructed in the correct location.

Use the dart board method :)

What happens when you superimpose record information onto your surveyed monument positions ? How close do they fit.
My thought process here is that there is open space inside of monuments that can accept the record information.
The worst case (perhaps what you have) is that the found monuments cannot fit record information at all, in which case you'll need to do some massage.

I think above suggestions kinda sorta say, there is no wrong way. My Dads thought was that if record was tangent, then that is a better case than non-tangent. holding radius is good also due to possible community minimum radius standards.

best wishes.

Sounds like you may be able to best resolve this using the Remnants Rule. That will give you justification for your resolution. If your unfamiliar with Remnants Rule, I suggest to research it as this pertains to curves.

Good luck and Happy Surveying