What if the graph contains multiple curves?
If the curves do not intersect, UN‑SCAN‑IT will follow each curve automatically. If the lines do cross, you can use color differentiation to follow the desired line, or the software can be automatically paused at the intersection points and digitizing resumed just beyond the intersection point. Then a cubic spline fit can fill the gap. In addition, UN‑SCAN‑IT has a Semi-Automatic Mode that can be used for intersecting lines or dashed and dotted lines.
