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Re: [ferret_users] reading ascii data directly onto a grid



Hi Martin,

You still need the /COLUMNS qualifier, which describes the organization of the data in the file.  The /GRID= qualifier describes the shape of the grid that PyFerret or Ferret will use to interpret the data once it's read in, acting very much like the RESHAPE function.

This data has all 10368 values in one record, so PyFerret needs that information.


yes? define axis/x=-180:180:2.5/edges/unit=degrees_east xd
yes? define axis/y=-90:90:2.5/edges/unit=degrees_north yd
yes? define grid/x=xd/y=yd gxy

yes? set data/ez/col=10368/var=cline/grid=gxy cf_01.txt
yes? shade cline

Without /COLUMNS=10368, only the first value of the first (and only) record would be read.

-Ansley


On 7/22/2019 1:11 PM, Martin Schmidt wrote:
Hi all,

the attached data file is complemented by a description, which allows to put the data onto a lat/lon grid.

Here is the definition of the grid. wc -w shows the correctness of the grid size.

yes? define axis/x=-180:180:2.5/edges/unit=degrees_east xd
yes? define axis/y=-90:90:2.5/edges/unit=degrees_north yd
yes? define grid/x=xd/y=yd gxy
yes? let gd = x[gx=gxy]+y[gy=gxy]

Now we read the data onto a line:

yes? set data/ez/col=10368/var=cline  lcf_01.txt

and reshape to the grid

yes? let cloud = reshape(cline,gd)

shade cloud shows a "good looking" plot of global cloud cover.

However, set data/ez offers the /grid attribute. So the following may work:

yes? set data/ez/var=cline/grid=gxy cf_01.txt
yes? sh data
    1> lcf_01.txt  (default)
 name     title                             I         J K         L
 CLINE    cline                            1:144     1:72 ...       ...

Looks good! However:

shade cline gives a strange plot and

yes? sh data
    1> lcf_01.txt  (default)
 name     title                             I         J K         L
 CLINE    cline                            1:144     1:1 ...       ...

Playing with the format and adding /del=delimited and so on does not resolve the problem.

Do I something wrong or is this a bug in pyferret 7.4 and 7.5?

Best regards,

Martin

--
Ansley Manke
NOAA/PMEL Science Data Integration Group
7600 Sand Point Way NE
206-526-6246

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