Partitioning is the process of ascertaining whether a subset of points can be regressed to a straight line, or to an arc. After partitioning, regression analysis can then be performed on the subset of points, which will result in PI points and curve radii.
No partitioning or regression analysis will be done. If the source polyline has bulges, then no regression analysis will be done. The bulge values will simply be used to calculate curve radii and the vertex positions to calculate PI points.
If the source polyline is derived from a survey of a road centreline, then Civil Designer can attempt to automatically partition the polyline vertices into linear and conical sections by using an Autoregressive moving average statistical model. If successful, the result will be a closest fit Horizontal alignment (straights and arcs). If the source data is not suitable for this type of analysis, Automatic partitioning will fail and present you with alternatives:
You can graphically indicate linear and conical subsets therefore manually doing the partitioning. Civil designer will then perform regression analysis on the specified subsets.
Extract Existing would be the appropriate method of extracting the original horizontal alignment from a polyline along the centre line of road design, where the vertices are exactly colinear or lie exactly on a circular arc. This method uses Demodulation algorithms to extract the alignment from the polyline.
No partitioning or regression analysis will be done. Each vertex of the source polyline will simply be extracted as a PI with zero radius.