Manually "drawing" line graph chart and export data

Question

I would like to manually create a line graph and then sample the created line to generate a data series from it.

Basically I have an idea, what a plotted values should look approximately and would like to be able to fine tune the chart, export the data and test on a 3rd party software if the drawn line fits the expected result.

I imagine there should be an option in excel/calc/some other software, which provide an "in-chart" editing and then replicating the changes on the original data set, but so far I wasn't able to find anything like this.

Do you know some why I can easily modify a line chart and get the samples data from it? It can be either in Microsoft excel, LibreOffice Calc, or some other software.

Answer 1

There is no way for that in Excel or similar program. Neither you can draw charts, neither it can read chart.

If you need to do it regularly then look for a specialized application.

If it's only one time, then I'd consider drawing it on a paper with mm scale and entering data manually.