Re: Converting GMT files to the netCDF format --- script

["Paulo B. Oliveira" <pbo@xxxxxxxxx>]

Hi All,

I'm sure others have also already written a script like
this, but here it is what I'm using to convert GMT cdf 
files do FERRET cdf...

--------------------------------
gmt2fer.jnl
-----------------------------------------------------
sp echo 's/z/var/'              > sed.cmds
sp echo 's/xysivare/xysize/'   >> sed.cmds
sp echo 's/xyvar2/xyz2/'       >> sed.cmds
sp echo '1,$s/NaN/-1.e+34/g'   >> sed.cmds
sp echo '1,$s/nan/-1.e+34/g'   >> sed.cmds

def sym tmp    *YOUR CHOICE*
def sym gmt_nc *YOUR CHOICE*
def sym fer_nc *YOUR CHOICE*

! -- Ferret doesn't like a var called Z. 
! ... Caution, this overwrites original file...
sp ncdump ($gmt_nc) | sed -f sed.cmds | ncgen -o ($tmp)
sp mv ($tmp) ($gmt_nc)

use ($gmt_nc) 

def ax/x=`x_range[i=1]`:`x_range[i=2]`:`spacing[i=1]`/units=longitude
xax
def ax/y=`y_range[i=1]`:`y_range[i=2]`:`spacing[i=2]`/units=latitude yax

let tpl   = 0*x[gx=xax]+0*y[gy=yax]
let var_r = reshape(var,tpl)

set mem/size=20

save/file=($tmp)/clobber var_r

canc var/all; canc data/all

use/order=X-Y ($tmp)

save/file=($fer_nc)/clobber var_r

-------------------------------------------------------------------

Ansley Manke wrote:
> 
> Hi Mark,
> Once you've written a NetCDF file, you can always read it
> and permute or flip the with, for instance, USE/ORDER=X-Y
> 
> For a description of this, go to this section in the Users Guide,
> "NetCDF, permuted axes, /ORDER qualifier".  The syntax
> must be used carefully.  ( I see we need more index entries
> pointing to this information!)  Here's one relevant bit:
> 
>      To indicate that the coordinates along a particular
>      axis are reversed  from the "right hand rule" ordering,
>      for example a Y axis which runs north to south (not
>      uncommon in image data), we would precede that axis
>      by a minus sign. For example
> 
>      USE/ORDER=X-Y my_flipped_images.nc
> 
> Hope this is what you need!
> 
> Ansley Manke
> 
> Mark A Ohrenschall wrote:
> 
> > Thanks, everyone, for your help -- it works!
> >
> > However, I have one small detail to take care of. The y-axis of the
> > grid
> > in the netCDF file is inverted, and I need to re-order the rows. I
> > tried
> > repeating my steps but this time transposing the coordinates (24 and
> > 31)
> > in the DEFINE AXIS/Y command, but that makes no difference.
> >
> > What can I do to re-order the y-axis?
> >
> > Thanks,
> >
> > Mark
> >
> > Mark A Ohrenschall wrote:
> >
> > > yes? DEFINE AXIS/X=-98:-81/npoints=20401 xax
> > > yes? DEFINE AXIS/Y=24:31/npoints=8401 yax
> > > yes? LET my_grid = RESHAPE(depth, x[gx=xax]+y[gy=yax])
> 
> --
> Ansley Manke  Pacific Marine Environmental Laboratory  Seattle WA
> (206)526-6246
>