Time lines with flexible time intervals...

**happychap** · 10-27-2012, 03:29 AM

I have a small series of data that includes: dates, irreguar times, and two columns of temperature data over the range 20 deg C to 40 deg C.

The dates are sequential, but the irregular times reflect observation times that may be taken once, twice or three times per day but at no particularly regular interval.
Obviously I want the observation times to relate to the actual time on each day... so that the temps are placed proportionately along the 24 hour time slot. For example, 08:00 would be one third the way through the 24 hour period, and 19:30 closer to 23:59.

Both temperature observations are taken at the same time.

In my mind's eye, I can see a 24 hour period, delineated by a date, with the observation times inserted along that continuum, and the temperature data above the observation time, with one line series differentiated from the other.

Any thoughts on how I can achieve this, or any help is greatly appreciated.

**Andy Pope** · 10-27-2012, 05:33 AM

Multi level category labels mean the axis will be treated as text and therefore equally spaced.

If you you combine date and time values and use a line chart the times will not be displayed correctly as Line chart groups by days.

You could use a xy-scatter if you combine the values.

**happychap** · 10-28-2012, 01:08 AM

Thanks Andy.
Does that mean "it can't be done"?

**Andy Pope** · 10-28-2012, 07:32 AM

No, as I said you can combine date/time values and then plot as xy-scatter.

**happychap** · 10-28-2012, 08:41 AM

Thanks, Andy.
I tried your idea but it made little difference to what I think it should look like. I think what I'll have to do is plot the time scale as "elapsed time", which seems to give a truer picture of the relationship of time and temperature over the period. It's just a botheration doing the conversions. I'm sure there is a way of automating these figures, but I haven't figured it out yet.