Redigitize timeseries chart record.

Hi,

I'm needing to redigitize old data from an old chart recorder. Why not generate new data with modern methods? It's a long story, but I'm stuck with it.

Because of fast risetimes, trying to do this task is too prone to error with usual hand operated movement of the cursor and cross-hairs.

I need to effectively use ginput(), but have the vertical cross hair be incremented in equal steps across the image (based on linspace) so that I only need to use the cursor to mark the y-value where my single channel trace intersects with the vertical cross hair. i.e. ginput with computer controlled increments of x, so that my points only need one-degree-of-freedom.

It is possible that this could be done by analysis of the trace, but unfortunately the trace is not that clean.

Is is possible that somebody has already done this? Or it is included in a tool box?

Thanks for any suggestion