RE: [ferret_users] Question on plotting ascii and netcdf information [SEC=UNCLASSIFIED]

[Savin Chand <S.Chand@xxxxxxxxxx>]

Thanks heaps Ansley.

 

I manged to do the required plotting following your recommendations and discussion.

 

Cheers,

Savin

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From: Ansley Manke [mailto:ansley.b.manke@xxxxxxxx]
Sent: Saturday, 18 August 2012 3:52 AM
To: ferret_users@xxxxxxxx; Savin Chand
Subject: Re: [ferret_users] Question on plotting ascii and netcdf information [SEC=UNCLASSIFIED]

Hi Savin,
There are several steps to this.

What you want to do is I think similar to what's described here, putting a set of labels at locations on a plot.
http://ferret.pmel.noaa.gov/Ferret/faq/labelling-dates-along-a-trackline   Is that right?  Or, reading your message again, maybe you want just one label corresponding to the date of the plot.

Either way you need to open and read the ascii file, and use the variables in it to make the labels. It would look something like this

yes? file/skip=1/var="lat,lon,clumb_num,timevar" my_ascii.dat

You want to make dates out of that time variable.  There's a discussion about that here,
http://ferret.pmel.noaa.gov/Ferret/faq/creating-a-time-axis-from-time-variables

but first you need to define separate variables for the year, month, day.

yes? let years = INT(timevar/10000)
yes? let months = int((timevar-10000*years)/100)
yes? let days = (timevar-10000*years) - 100*months

yes? ! check this
yes? list/i=1:5 years, months, days

yes? ! Now following what's in the FAQ above,
yes? let tstep = DAYS1900(years[d=1],months[d=1],days[d=1])

yes? ! Define a time axis, ttaxis, from variable tstep
yes? DEFINE axis/T/T0=1-jan-1900/UNIT=days ttaxis=tstep[L=1:`tstep,i=@ngd]`]

yes? ! put the lon,lat,clump data onto this time axis
yes? let tt = t[gt=ttaxis]
yes? let lat_t = reshape(lat[d=1], tt)
yes? let lon_t = reshape(lon[d=1], tt)
yes? let clump_t = reshape(clump_num[d=1], tt)

Depending on what you want to do, you could regrid the vorticity data to the time axis we defined here from the ascii data. Then you could step through that time axis, plotting the vorticity data and making the label, using the LABEL command and specifying the longitude, latitude, at the particular time as the location and the clump_t variable as the text of the label.

I hope this will get you started.

On 8/15/2012 11:41 PM, Savin Chand wrote:

Dear ferret users,

 

Please advice how I can solve the following problem in ferret...

 

I have a netcdf data containing daily averaged relative vorticity (say for January 2000).f

 

I also have an ascii file containing the following information:

Lat	Long	Clump_number	Time
20.5	120.5	1	20000105
30.5	180	2	20000108
8.6	170	3	20000111
9.4	126	4	20000114
25.6	75	5	20000117
.	.	.	.
.	.	.	.
.	.	.

 

I can generate maps of relative vorticity for each day from the netcdf file but cannot plot the clump number in the corresponding relative vorticity map at the respective latitude-longitude position as given in the ascii file. I can do it manually though using "label" command one at a time.

 

Can anyone please advice how I can automate it as I will be dealing with a large number of files.

 

Your help will be very much appreciated.

 

Thanks.

Savin