Re: [ferret_users] synchronizing an i/j/k grid with another lon/lat/z grid

[Ge Peng <gpeng@xxxxxxxxxxxxxxxxxxxxxxx>]

> Hey Peng,
> try to see more into the grids with command
> "show grid vmode[d=1]"
> "show grid u[d=2]"
> It helps a lot. It should say something like this:
>  GRID GKK1
>  name       axis              # pts   start                end
>  XAX       X                   87 r   -10.75               32.25
>  YAX       Y                   77 r   34.25                72.25
>
> (1) You can change the grid of one of the two variables to be the same:
>
> "let u_new=u[d=2,g=GKK1]"
> then "let dmode=vmode[d=1]-u_new"
>

Hi Peter,

This one works well for me. Thanks a lot!

--- Peng

> (2) You can cut the variable on the bigger region:
>
> let vmode_small=vmode[d=1,j=97:200]
>
> (3) Or you can define new axis and change the grid of the two variables
> with
> something like this:
>
> def axis/x=-90:90:0.5 newx
> def axis/y=-90:90:0.5 newy
> def axis/z=1:50:1 newz
> def grid/x=newx/y=newy/z=newz grd
> let u_new=u[d=2,g=grd]
> let vmode_new=vmode[d=1,g=grd]
>
> Hope this helps,
> Cheers, Peter
>
>
>
> On Thu, Sep 25, 2008 at 12:25 AM, Ge Peng
> <gpeng@xxxxxxxxxxxxxxxxxxxxxxx>wrote:
>
>> Hi Ferreters,
>>
>> I have two datasets:
>>
>> Grid in dataset 1:
>> X=1:360:1; Y=1:200:1; Z=1:50:1
>>
>> Grid in dataset 2:
>> X=geolon(i=1):geolon(i=360):1, which is from -279.5 to 80.5 every 1 deg
>> Y=geolat(j=1):geolat(j=200):dlat(j), which is from -83 to 89 with
>> varying
>> dlat.
>> Z=z(k=1):z(k=50):dz(k), dz varies.
>>
>> I need to perform adding or subtracting functions between variables from
>> those two data sets.
>>
>> yes? let dmode=vmode[d=1]-u[d=2]
>> yes? sha dmode[k=1,l=1]
>>
>>  *** NOTE: Ambiguous coordinates on X axis: VMODE[D=1]-U[D=2]
>>  **ERROR: inconsistent sizes of data regions: Y axis
>>          U[D=2] has 104 points (J=097:200)
>>          expression has 200 points (J=001:200)
>>
>>  How do I synchronize these two grids?
>>
>>  Thanks,
>>
>> --- Peng
>>
>> -------------------------------
>> The version of ferret and dataset info:
>>
>> > ferret
>>        NOAA/PMEL TMAP
>>        FERRET v6
>>        Linux(g77) 2.4.21-32 - 08/23/06
>>        24-Sep-08 14:54
>>
>> yes? sho data
>>     currently SET data sets:
>>    1> ./dynmode_cm21_ocn_stress.nc
>>  name     title                             I         J         K
>>  L
>>  NI_DIM   model i-dimension                ...       ...       ...
>> ...
>>  NJ_DIM   model j-dimension                ...       ...       ...
>> ...
>>  NK_DIM   number k-dimension               ...       ...       ...
>> ...
>>  NMODE_DIM
>>          number of modes in file          ...       ...       ...
>> ...
>>  RC       displacement mode eigenvalues    1:360     1:200     1:5
>> ...
>>  VC       velocity mode eigenvalues        1:360     1:200     1:5
>> ...
>>  RMODE    displacement modes               1:360     1:200     1:50
>>  1:5
>>  VMODE    velocity modes                   1:360     1:200     1:50
>>  1:5
>>  RN2      buoyancy frequency square at la  1:360     1:200     1:50
>>  1:5
>>  VN2      buoyancy frequency square at la  1:360     1:200     1:50
>>  1:5
>>
>>    2>
>> /host/crab/data02/gpeng/cm2.1p0_oda/dta/ocn_stress_sim/
>> 19930101-20.ocean_5days.uvts.nc
>>  (default)
>>  name     title                             I         J         K
>>  L
>>  TEMP     Potential temperature            1:360     1:200     1:50
>>  1:5
>>  SALT     Salinity                         1:360     1:200     1:50
>>  1:5
>>  U        zonal current                    1:360     1:200     1:50
>>  1:5
>>  V        meridional current               1:360     1:200     1:50
>>  1:5
>>
>>
>> yes? list vmode[i=116,j=163,k=1,l=1,d=1]
>>             VARIABLE : velocity modes (non-dimensional (unit norm over
>> depth))
>>             FILENAME : dynmode_cm21_ocn_stress.nc
>>             X        : 116
>>             Y        : 163
>>             Z        : 1
>>             T        : 1
>>          0.04642
>> yes? list u[i=116,j=163,k=1,l=1,d=2]
>>             VARIABLE : zonal current (m/sec)
>>             FILENAME : 19930101-20.ocean_5days.uvts.nc
>>             FILEPATH :
>> /host/crab/data02/gpeng/cm2.1p0_oda/dta/ocn_stress_sim/
>>             LONGITUDE: 164W(-164)
>>             LATITUDE : 53N
>>             DEPTH (m): 5
>>             TIME     : 03-JAN-1993 12:00 JULIAN
>>          0.03713
>>
>>
>>
>