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Re: [ferret_users] Question on Regridding
And the opposite is also something to pay attention to: if an x-axis is marker "modulo" when you don't want it to be.
If you give Ferret data on a partial longitude axis (say just the Pacific), it will still be modulo in x. That means that operations across all gridpoints (for example smoothing) will wrap across the break. That will often not be what is intended (and you might not be aware of it).
The solution is:
CAN AXIS/MODULO axis_name
I do this every time I'm working with a non-global longitude axis to avoid unintended results.
BK
On Oct 4, 2012, at 10:31 AM, Ansley Manke wrote:
> Hi Paul,
> It's hard to say based on this, but one thing to check is whether the longitude axes are being treated as modulo axes, and if both have units of degrees_east, so that Ferret can reconcile the range of longitudes on the two grids.
>
> yes? show grid slr[d=1]
>
> yes? show grid slr[d=2]
>
> The #pts column for the x axes should contain an "m" for modulo. That is, the "180mr" in the listing below is saying that the x axis has 180 points, is modulo, and is regularly spaced.
>
> yes? use coads_climatology
> yes? sho grid sst
> GRID GSQ1
> name axis # pts start end
> COADSX LONGITUDE 180mr 21E 19E(379)
> COADSY LATITUDE 90 r 89S 89N
> normal Z
> TIME TIME 12mr 16-JAN 06:00 16-DEC 01:20
> normal E
> normal F
> If one of the axes is not marked as being modulo, then you could get what you are seeing. You can fix these properties on an axis with the SET AXIS command,
>
> SET AXIS/MODULO/UNITS="degrees_east" `slr,return=xaxis`
>
> Ansley
>
> On 10/3/2012 7:28 AM, Paul Goddard wrote:
>> Hi, I am attempting to regrid a variable SLR gridded on ACCESS1.0 (x=-0.5:359.5, y=-0.5:299.5 i=1:360, j=1:300) to the grid provided by the variable SLR gridded on GFDL-CM3 (x=80E (-280) :80E, y=82S:90N i=360, j=200).
>>
>> I ran the following script:
>>
>> yes? USE GFDL-CM3_SLR.nc
>>
>> yes? USE ACCESS1.0_SLR.nc
>>
>> yes? let ACCESS10_SLR = SLR[g=SLR[d=1]]
>>
>> yes? save/file=ACCESS10_SLR_REGRID.nc ACCESS10_SLR
>>
>>
>> But when I attempt to shade ACCESS10_SLR I only get a plot with a region around austrailia in the upper right corner and the rest of the plotting space is white. Any ideas?
>>
>> Thanks,
>> Paul
>>
>
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