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R= vs L= Quick Question

(@airpix)
FNG Member
Joined: 2 months ago
Posts: 1
December 6, 2018 6:08 am

I am a landowner and don't have any experience reading a survey plan. Could some one tell me what the actual frontage along the road is in regards to the attached small portion of our plan? Is it  L=167.25' or R=220.00' ? I assume it's 167.25" but I would greatly appreciate knowing for sure.

John / Airpix

(@tim-reed)
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Joined: 9 years ago
Posts: 105
December 6, 2018 6:13 am

L= Length of Curve, or Arc Length.

Delta= Angular difference of the radial lines intersecting the two end points of the curve known as the PC (Point of Curvature) and PT (Point of Tangency)

167.25 is the lot frontage.

(@dave-karoly)
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Posts: 10020
December 6, 2018 6:16 am

L=length along the curve.

The triangle=delta=the included angle of the arc.

((43°33'24"/360)*440)*3.1416)=167.25'

O death, where is thy sting? O grave, where is thy victory? -1 Corinthians 15:55

(@jim-frame)
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December 6, 2018 6:21 am

Perhaps the most important thing for the owner to realize is that the frontage distance of 167.25' is measured along the arc.  If he stretches a tape from one front corner toward the other and measures the frontage distance, he's going to overshoot the other corner.  The chord (straight-line) distance is only 163.25'.

Jim Frame
Frame Surveying & Mapping
609 A Street
Davis, CA 95616
framesurveying.com

dms330, FL/GA PLS., Cee Gee and 2 people liked
(@john-putnam)
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December 6, 2018 6:53 am

Another quick heads up to the OP.  When surveyors work in feet it is conventionally annotated in decimal feet.  Thus the .25' = 3".

John Putnam, PLS
OR, CA, WA & ID

(@holy-cow)
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December 6, 2018 11:22 am

You guys jumped in very well on this.  Hope the original poster understands now.  The comment on the small difference, in this case, between the arc length and a straight-lined measurement is very important.  For a very different radius the difference can be very important.  For example, on a radius of 50 feet with a straight distance of 100 feet between the ends the arc length could be as much as 157 feet.

(@bill93)
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December 6, 2018 12:39 pm
Posted by: holy cow

The comment on the small difference, in this case, between the arc length and a straight-lined measurement is very important.

I wouldn't call 167.25 versus 163.25 a small difference.

(@thebionicman)
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December 6, 2018 1:22 pm

If you're buying it's huge, selling not so much...

CFedS, PLS ID-OR-WA-UT-NV

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