Re: Temporal graphs on Schema2

In message of 17 Jan, G Robin Edwards <robin.edwards@xxxxxxxxxxxxx> wrote:

> In article <2adb1eea4d.tim@xxxxxxxxxxxxxxxxxxxxx>, Tim Powys-Lybbe
> <tim@xxxxxxxxx> wrote:
> > I am trying to make a simple graph of interest rates, you know rates
> > up and down the Y axis and dates along the X axis. I use Schema2 v.
> > 1.06a4.
>
> > I've got the graph OK now but the X axis just displays the day
> > numbers as days since 1900, from 35000 (1900 odd) to 38000 (2004 odd)
> > and I would like to see something like years instead.
>
> > The real complication is that the scale of the X axis has to be days
> > as the interest changes in my data set occur at random intervals. So
> > I have two columns of data: the first is the days since 1900 but
> > formatted to display calendar date and the second is the interest
> > rate. In other words the source data for the graph has the dates in
> > day-month-year format but won't transfer this format to the graph.
>
> > Does anyone have any ideas on how to display the X axis as I want it?
>
> > In case anyone's interested, I've put the Schema2 *** on:
>
> > www.southfarm.plus.com/riscos/BaseRates.zip
>
> 1st - which I am sure you know all about, does not have a date variable
> facility. Since I produce large numbers of time series plots, and
> other plots which have a time variable of some sort on the X axis I
> have to do something to produce a continuous time scale, so what I do
> is to generate what I call decimal years, for example 2006.453. For my
> purposes the dates do not have to be completely accurate, so I use a
> simple conversion method that may introduce an error of perhaps half a
> day occasionally. It seems to work quite well, but may not suit an
> accountant, I suppose.

Thanks for that. I think I can see what you mean:

The current X-axis data is day numbers (from 1900) formatted to appear
as calendar dates.

I could convert this easily to Year numbers with decimals of a year.
Possibly format these to show only the integer part.

Use the new year numbers to provide a new X-axis which should,
hopefully, display itself on the graph as integer years.

Currently I am up to eyeballs in tax returns (the base rates data was
part of the process) so I will get back to it when this ghastly job is
finished.

--
Tim Powys-Lybbe                                          tim@xxxxxxxxx
             For a miscellany of bygones: http://powys.org
.

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