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Civil 3D Best Fit Line
Posted by john-putnam on November 25, 2019 at 6:41 pmDoes anyone know if there is a way to assign an initial offset to points in the create line by best fit routine. I’m trying to create common center-line from tied monuments with varying offsets of record. I.e some are actual center-monuments while some at 30 foot offsets and still others are at 40 foot offsets.
Thanks in advance.
John
steven-metelsky replied 4 years, 9 months ago 9 Members · 9 Replies -
9 Replies
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Or you can add a screenshot for me to see what you want and keep the conversation here so everybody can see
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I’ve never had to do that before but look into creating a best fit alignment, you’re going to have more options than in the Line by Best Fit routine. Good luck!
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In cases where I have points on right of way lines on both sides of center, and I’m trying to establish a best fit centerline, here is what I do:
- Establish a rough centerline direction, perhaps by best fitting the monuments on one side.
- Draw a line perpendicular to that line, exactly as long as the right of way half-width.
- snap copies of that line to the right of way monuments.
- Do a best fit line by selecting “points on the screen”, snapping to the line endpoints opposite the monuments.
If the rough centerline direction determined in step 1 turns out to be too rough, I might have to run through the process a second time.
If C3d was survey software it would have a much better option.
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1. draw a circle on the the offset monuments (radius=offset)
2. c3d best fit of a line ‘by selecting on screen’
3. when selecting the offset circles use osnap ‘near’ and eyeball the tangent point
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I have drawn a line between the two circles by snapping tangent one each.
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From what I understand, you have a series of monuments along a centerline. Each one is at a different offset.
If I had any idea of the general direction, I would simply create a point at the offset distance, and use those calc points for a best fit. Then you could refine that by using it as a reference for perpendicular, calculating new offset points, and then doing a best fit. I would imagine that two or three iterations would be sufficient to get into “It doesn’t matter anymore” range.
-All thoughts my own, except my typos and when I am wrong. -
I think I would initially create a circle about each offset monument with radius equal to its offset value and then draw a series of tangent lines connecting all the circle tangent points. Use Civil 3D Best Fit Line routine and use the created tangent lines as your sample entities. At least this is how I understand the problem. Hope this helps.
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Are you trying to establish a baseline for a county ROW or are you trying to use Civil 3d for Boundary Analysis?
If for a Route Survey (baseline): draw circles from the monuments at their respective offsets from center line. Then draw a line tangent to said arcs. Zero Fillet to create any angle points. Assign points to those angle points and do a best fit on those alone. That should get you close if not right on where you need to be.
Edited: TickMagnet pretty much said what I eluded to.
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