@jacob.small Thanks for this valuable info.
Just to clarify: Continuing the discussion from Fit the curves in geometry …polyline to geometry line:
I have devided the lines in to say 20 parts and each part is filtered with bounding box to collect the existing points inside the box. and tried to fit an arc for that portion through points.
Issue was that one point at the edge of bounding box was only considered once and thus resulting in gaps in the arc so need to add points again to the previous list just to get a continues arc.
This is what i was doing manually at the time of creating that alignment and trying to replicate the same in code now.
I know there are still hurdles in the approach but lets take one step at a time by dividing the problem. Once best fit arcs are done then the big issue will be the connection at end and tangency between the arcs, also what if points are more or less in straight line …hope to find a solution for that too.