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"
(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