Abstract When Visvalingam’s algorithm was first presented, it was noted that it could be driven with any metric to suit different purposes, types of features and degrees of generalisation. It was illustrated with the concept of the effective area (EA). The intelligent application of metrics with and without weighting requires the prior segmentation of polylines with heterogeneous shapes into geometrically similar sections. Automatic line segmentation remains a research challenge. Meanwhile, different weighting functions have been used with different types of lines as noted in this paper. EA has a tendency to output spiky lines. Attempts have been made to give less weight to acute angles and favour obtuse angles. This yields visually more pl...