Time Scales of Plots

[geomat0626]

I have a concern about the way Vensim displays the horizontal scale.

I generated a simulation run and used the custom graph option to displays real data and simulated data. The simulation time is from 2005 to 2050 represented as Time 0 to 540.

For displaying the graph I selected the plot to show from 0 to 132 months.

Why do Vesim show the graph as 2 scale divisions for the 1st year and then 1 scale division per year there after?

Please find the plot attached.

Thank you

George

[tomfid]

You have 6 divisions of 11 years here, which is a little unnatural because that means 22 month intervals. However, the labels are misleading, because they don't indicate the lack of precision - those dates should be Oct. 2006, Aug 2008, June 2010, ...

I'll see what we can do to improve the display. In the meantime, I'd either show 11 intervals or pad the chart with extra years to make things work out.

[geomat0626]

Thanks for the reply Tom.

I redid the simulations with the END TIME to be 126 months and the plot is a bit better but something still seems amiss

This large print seems to show beginning and ending of years but still 2008 and 2011 has only one scale division.

My timestep for the model is 0.015625.

As you mentioned, it might not be a precision issue but it is hard to convince a mathematician (My thesis supervisor) about these scales

Thank you
George

[tomfid]

It's not an internal precision issue; it's that the label is apparently using the integer truncation of whatever the real date is.

126 won't work because 126/6 = 21 months.

144 months with 6 divisions or 132 with 11 divisions should work though.

[geomat0626]

Thanks for this Tom.

I assumed it was because of the real data (lots of data point are not populated)

I will try it to see.