Re: time axis by 30min increments

[Ansley Manke <Ansley.B.Manke@xxxxxxxx>]

Hi Steve,
Add these commands and I think you'll see that this is a precision
problem; the underlying plotting package cannot represent the
numbers accurately enough.

yes? show axis time
yes? list/prec=8 t[gt=tax]

The default time origin is 15-Jan-1901, and there is not enough precision
to measure all that time in minutes.

To solve this, define your axis with a more recent time origin

define axis/t="02-feb-2002:16:00:00":"02-feb-2002:17:00:00":30\
/units=minutes/T0="1-jan-2000" tax

Steve Knox wrote:

> Hi,
> I'm trying to define a time axis with 30min increments as follows:
> The data file "test.dat" consists of 3 lines:
> 1.0
> 2.0
> 3.0
>
> yes? define axis/t="02-feb-2002l:16:00:00":"02-feb-2002:17:00:00":30\
> yes? /units=minutes tax
> yes? define grid/t=tax g1
> yes? file/var=xx/grid=g1 myfile.dat
> yes? list xx
>              VARIABLE : XX
>              FILENAME : test.dat
>              SUBSET   : 3 points (TIME)
>  02-FEB-2002 16:00:00 / 1:  1.000
>  02-FEB-2002 16:30:00 / 2:  2.000
>  02-FEB-2002 17:00:00 / 3:  3.000
> yes? plot xx
> yes? frame/file="/data/ojima/web/vemap2/test.gif"
>
> The times area ok and the data is ok but the plot is NOT a straight line
> and the time (x) axis labels are messed up.
>
> What am I doing wrong?
>
> Steve Knox
> NREL
> Colorado State University