Re: [ferret_users] How to read ASCII data accurately

[Martin Schmidt <martin.schmidt@xxxxxxxxxxxxxxxxx>]

Thanks Russ and Akshay for the suggestions.

It turns out that I need to be mor specific.

The file contains a space delimited list of 28 variables in 28 columns. 
The first column is the critical time variable.
My command to open the file is:

set data/ez/format=delimited/col=28/skip=1/del=" " 
"RAW/davis_msm184_30min.dat"
define axis/t/units=day/t0="1-jan-0000 00:00"/from_data time=v1
 *** NOTE: Axis has repeated values -- micro-adjusting ...

This is from the missing accuracy of the time variable in v1. Adding the 
/type="numeric" argument does not change this.

Alternatively,

set 
data/ez/col=28/skip=1/var=v1,v2,v3,v4.v5,v6.v7.v8.v9,v10,v11,v12,v13,v14,v15,v16,v17,v18,v19,v20,v21,v22,v23,v24,v25,v26,v27,v28 
"RAW/davis_msm184_30min.dat"
 *** NOTE: attempt to initalize 24 variables
 *** NOTE: maximum allowed is 20 variables
However, reading data this way
define axis/t/units=day/t0="1-jan-0000 00:00"/from_data time=v1

generates the desired time axis. Hence, reading the variables separately 
without a format specifier gives the correct answer. But now I have to 
split the file.

Generating a testfile with one column only

set data/ez test.dta

reads data correctly.

So my conclusion is, that the missing precision is coupled to the fact, 
that I open the file in the delimited format.

Cheers,
Martin





Russ Fiedler wrote:
> Hi Martin,
>
> Version 6.82 RH6 reads this to full precision so it looks like a
> difference between OS or a bug has crept in.
>
> russ-hf% ferret -nojnl
>          NOAA/PMEL TMAP
>          FERRET v6.82
>          Linux 2.6.32-279.1.1.el6.x86_64 64-bit - 08/03/12
>           3-May-13 09:55
> yes? file/var=xx dummy
> yes? list/prec=10 xx
>               VARIABLE : XX
>               FILENAME : dummy
>               X        : 1
>            734707.0101
>
> There also the /TYPE=r8 qualifier which might work or try specifying the
> Fortran format explicitly.
>
> Russ
>
> On Thu, 2013-05-02 at 17:50 +0200, Martin Schmidt wrote:
>    
> > Hi,
> > I have an ASCII input file. One variable is the Julian day (from 0000)
> > and looks like
> >
> > 734707.010069
> >
> > Reading this with set data/ez I find
> >
> > list/prec=10 v1
> >
> > 1   / 1:  734707.0000
> >
> > which is not, what I would like to get.
> >
> > I am using ferret_v6842_rh5, which should use real*8 accuracy for
> > operations.
> >
> > Is there a way to read ASCII data with the same accuracy?
> >
> > I do not know, who had the idea to use this far away time origin, the
> > data are as they are. Possibly
> > for compatibility with EXCEL.
> > For sure, I could edit the input file, remove the first four digits of
> > the time variable and add this
> > after reading the data. This workaround is fine for my example, but for
> > a larger project I am interested in a
> > more general solution with ferret - if it exists.
> >
> > Many thanks,
> > Martin Schmidt
> >
> >
> >      
>