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Re: Reverse data
On Feb 4, 5:08pm, beland@CERCA.umontreal.CA wrote:
> Subject: Reverse data
> Hello all,
>
> I am trying to plot a 2-d field on the globe. The data is written in a
> Fortran unformatted file. I read it with the following:
>
> define axis/x=0:357.5:2.5/unit=degrees x144
> define axis/y=90S:90N:2.5/unit=degrees y73
> define grid/x=x144/y=y73 g144x73
>
> file /var=precip/grid=g144x73/format=UNFORMATTED/COLUMNS=`144*73`
precip79.out
> ppl shakey 1,1,0,0,-3
>
> fill /line/key/title="Total Precipitation (mm)"/i=1:144/j=1:73 precip
>
> The problem is that the output is upside down, since the data is stored
> from North to South instead of from South to North. How can I tell
> ferret to reverse the data and only the data (not the axes) ? I know I
> could write a Fortran program, but I thought that ferret ought to be
> able to do this.
===============================================================
Hi Michel,
Here's what you have to do (for now):
i. yes? SAVE/file=precip79.cdf precip
ii. exit ferret
iii. ncdump precip79.cdf > precip79.cdl
iv. edit the precip79.cdl file to **reverse the order of the points on the Y
coordinate axis**. Let Ferret help: cut and paste the output of
yes? list/y=90s:90n/format=(10(F6.1,","))/order=y -1*y[gy=y73]
v. ncgen -o precip79_reversed.cdf precip79.cdl
vi. yes? use precip79_reversed
Ferret is capable of reversing data that it reads from a NetCDF file, although
it is not presently capable of doing the same from an ASCII or binary file.
cheers - steve
PS: We will be adding a "@REV" (reversal) transform in a near future version
that will make solving this problem much simpler.
--
| NOAA/PMEL | ph. (206) 526-6080
Steve Hankin | 7600 Sand Point Way NE | FAX (206) 526-6744
| Seattle, WA 98115-0070 | hankin@pmel.noaa.gov
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