How to mark a line crossover point on a chart automatically?

Hi again guys,

I would be grateful for any info you can provide regarding adding a crossover point mark on a chart. I have a set of values that start below zero and then become positive. I would like to add some kind of automatic mark at the point the values cross above zero. The graphs are automatically updated depending on some values, so the mark should be automatically placed at the crossover point.

It would also be helpful if on a chart with many lines i could select two of the sets and have them show a mark at their crossover point (i.e. not an axis-crossover, but two line crossover)

Any simple way of doing these two things in excel 2013?

Thank you very much once again!

Anyone please? How to automatically emphasize the crossover point of two lines on a chart?

Excel is not going to do this automatically. Here's how I would do it.

1) Based on the input data, find a place in the spreadsheet and calculate the x-intercept in a format that works for the data layout and chart type you are using. Assuming an XY scatter chart and numeric data for both y and x, this could be done using a linear interpolation type algorithm or maybe you would prefer a curve fitting type algorithm.
2) Using this calculated point, add the crossover point as a second data series on the chart and format as you would like it to appear.