I have a line chart where the x-axis is taken from a column containing the name of each row of accounting-month data (ie. not strict calendar months). I want a major grid line every twelve accounting months, but because the scale format is “text” this does not seem to be an option. I have tried re-defining the scale as “date” but this only offers grid intervals based on a number of days, not periods.
My requirement must be very common and it isn’t an issue in Excel, so I think I must be missing an obvious solution here.
In response to LeroyG, I am using version 220.127.116.11 and I am attaching a sample file (assuming my first attempt at this works)
New information: I have just discovered that the problem I am having disappears when I delete the final row of my spreadsheet (row 89 in the sample file). When I do this after following your instructions I can see monthly minor gridlines and yearly major gridlines exactly as I want them.
If it is any sort of clue as to what is going on, copy row 89 into a new row 90, and then delete 89 and this makes the chart work properly too, even though the data should be exactly the same. It is unfortunate that I tried to modify my chart immediately after both updating LibreOffice and also creating the new row in my spreadsheet, as I now have no idea which change gave rise to the issue.