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Help with curve description

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(@kscott)
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Surprisingly, I have no experience with the following terminology in a curve description and I could use a little help regarding the proper interpretation: "thence westerly to the left along an arc of 477.52 feet radius 383.0 feet, measured on 25 foot chords:"
Is this calculated as the fifteen 25 foot chords plus the remaining 8 foot chord?
Thanks

 
Posted : July 21, 2014 12:50 pm
(@brad-ott)
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> Surprisingly, I have no experience with the following terminology in a curve description and I could use a little help regarding the proper interpretation: "thence westerly to the left along an arc of 477.52 feet radius 383.0 feet, measured on 25 foot chords:"
> Is this calculated as the fifteen 25 foot chords plus the remaining 8 foot chord?
> Thanks

I am guessing that it is calculated with the 477.52 & 383.0 bits. They are just telling you that they measured it out in the field along the 25 feet chord segments?????

 
Posted : July 21, 2014 12:55 pm
(@kscott)
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I think you are correct. I realized that at that radius the arc length of a 25 feet chord is 25 feet! Thanks for the reply.

 
Posted : July 21, 2014 1:06 pm
(@bill93)
Posts: 9834
 

Chord 25.000 gives arc 25.00286, so over the full length you'll be off by about the magic number 0.04 between arc and sum of chords.

The radius looks like it was chosen to give exactly 3 degree delta per 25 ft chord (actually 477.519).

 
Posted : July 21, 2014 1:51 pm