The following works! It should not, but it does.
!Read only the first column into variable v1. Define the time axis
set data/ez/skip=1/var=v1 "RAW/davis_msm184_30min.dat"
define axis/t/units=day/t0="1-jan-0000 00:00"/from_data time=v1[d=1]
define grid/t=time tgrid
let tdummy = t[gt=tgrid]
!Open the same data set again, now as delimited data set. Now only
real*4 accuracy is used
set data/ez/columns=28/skip=1/format=deli/del=" "
"RAW/davis_msm184_30min.dat"
let v21 = reshape(v2,tdummy)
let v31 = reshape(v3,tdummy)
let v41 = reshape(v4,tdummy)
...
....
!Listing v1 and time gives different results
list/i=1/prec=12 v1
VARIABLE : V1
FILENAME : davis_msm184_30min.dat
FILEPATH : RAW/
X : 1
734707.000000
This is wrong!
yes? list/l=1/prec=12 t[gt=time]
VARIABLE : T
axis TIME
TIME : 24-JUL-2011 00:14
734707.010069
This is correct, but v1 is defined twice! Here the first definition
(correct) is used.
list/l=1:10 tair
24-JUL-2011 00:14:29 / 1: 23.58
24-JUL-2011 00:45:00 / 2: 23.32
24-JUL-2011 01:14:59 / 3: 23.22
24-JUL-2011 01:44:29 / 4: 23.22
24-JUL-2011 02:15:00 / 5: 23.18
24-JUL-2011 02:44:59 / 6: 23.12
24-JUL-2011 03:14:29 / 7: 23.01
24-JUL-2011 03:45:00 / 8: 22.98
24-JUL-2011 04:14:59 / 9: 22.80
24-JUL-2011 04:44:29 / 10: 22.69
gives correct temperature and correct times.
yes? sh/brief data
currently SET data sets:
1> RAW/davis_msm184_30min.dat (default)
The data set is only opened once.
Something is going on in the background, which is not ferret-like.
Usually I would expect, changing v1 would imply changes in
the definition of the time axis too.
____________
Nevertheless, I think the fact that a line like
set data/ez/columns=28/skip=1/format=deli/del=" "
"RAW/davis_msm184_30min.dat"
truncates the data should be considered as a bug?
Martin
Martin Schmidt wrote:
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