RE: Time axis

["Kwok,Ken [PYR]" <Ken.Kwok@xxxxxxxx>]

Thanks Steve, I still need some clarifications now that I understand the
DAYS1900 command.

Is it possible for Ferret to recognize hours and minutes in an ASCII
dataset?  Also, when I use the SCAT2GRIDLAPLACE_XY external functions, is it
possible to define T-axis as X?

Thanks,
Ken

-----Original Message-----
From: Steve Hankin [mailto:hankin@pmel.noaa.gov]
Sent: Friday, August 03, 2001 3:58 PM
To: Kwok,Ken [PYR]
Subject: Re: Time axis


Hi Ken,

Did you get an answer to this?

Ferret V5.4 will be able to read your ASCII file and make sense of the
dates. In
current versions Ferret needs to either be able to read the file with rigid
columns (readinging month, day, year as separate variables) -- this would be
SET
DATA/FORMAT="(FORTRAN format)" -- or use system utilities (e.g. Unix "sed")
to
change the "/" into a comma and use the "FILE" command alias.

The DAYS1900(year,month,day) allows you to convert the year,month,day
variables
to a Julian day. Use that in
    DEFINE AXIS/T=="1-jan-1900"/units=days my_axis =
DAYS1900(year,month,day)

Now you have your time axis.  You can use the @ASN regridding transformation
to
tell Ferret to regard this axis as the axis of your data.

All of these topics are described in the Ferret Users' guide.

    - steve

========================

"Kwok,Ken [PYR]" wrote:

> Hello Ferreters,
>
> I have a question regarding time axis and NetCDF file formats.  I have a
set
> of ASCII data with columns of date, time, pressure, and humidity.  The
data
> is scattered (ie. no regular time intervals, pressure intervals etc).  The
> date format is YYYY/MM/DD and the time format is HH:MM:SS.  If I want to
> graph the time axis in a continuing basis with hourly increments, do I
have
> to covert my ASCII file into NetCDF format?  I have no experience in
NetCDF
> files at all.  What I eventually want to do is to have a graph of pressure
> versus time, with contours of humidity.  I know I can accomplish this
using
> SCAT2GRID functions but I don't know how to get Ferret to recognize the
time
> axis.
>
> Any help would be much appreciated.
>
> Thanks,
> Ken
>
> ---------------------------------
> Kenneth Kwok - UBC MET Co-op
> Applications and Services
> Meteorological Services of Canada
> Pacific and Yukon Region
> Telephone: 604.664.9179

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