# Re: [ferret_users] Correlation between one point and 2D spatial data

Hello Sir,
Check the time axis.And specify the time axis while assiagning P and Q.
Here your data is daily,so according to the time axis there will be 504 points.Also you didn't mention the location,so lets just say current at 90E and sla at the equatorial indian ocean.After specifying the all axis then it will look like the following,then go for the correlation.

use daily-current.nc
use daily-ssh.nc
set mem/size=600

let p = u[d=1,l=1:504,x=90E,y=0]
let q = sla[d=2,l=1:504,x=40E:120E,y=10s:10n]
go variance

can data/a
can var/a
can mem

Hope it will solve your error.

--
Regards,
Chinnu Sachidanandan
Physical Oceanography Division
National Institute of Oceanography
csachidanandan@xxxxxxx

On Fri, Jan 15, 2016 at 12:37 PM, 'Iskhaq Iskandar' via _OAR PMEL Ferret Users wrote:
Dear Ferret users,

I am trying to compute a correlation between an observed current at one location (1D data: varies in time only) with SSH of a basin-wide region (2D data in x,y and time).

What I did is something like this:

-------------------
use daily-ssh.nc
use daily-current.nc
set mem/size=600

def axis/t=1-jan-2009:19-May-2010:1/unit=days tday
let ssh = sla[d=1, gt=tday]
let uvel = u[d=2, gt=tday]

let p = uvel
let q = ssh
go variance

!
can data/a
can var/a
can mem
--------------------

But I got an error like:

-------
*** NOTE: Ambiguous coordinates on X axis: P*Q-P*Q + 1
*** NOTE: Ambiguous coordinates on X axis: Q*MASK_PQ
**ERROR: dimensions improperly specified: must be a 2D region
--------

If I change between P and Q, I will get an error like:

--------
*** NOTE: Ambiguous coordinates on X axis: P*Q-P*Q + 1
*** NOTE: Ambiguous coordinates on X axis: Q*MASK_PQ
**ERROR: inconsistent sizes of data regions: X axis
Q has 3 points (I=0:2)
_expression_ has 301 points (I=001:301)
---------

Do you have any suggestion?
Thank you for help.

Best regards,
Iskhaq

---------------------------------------------------------------- Dr. Iskhaq Iskandar Jurusan Fisika, Fakultas MIPA Universitas Sriwijaya Kampus Inderalaya, Ogan Ilir (OI) Sumatra Selatan, 30662 INDONESIA Phone: +62 (711) 580743 Fax: +62 (711) 580268 E-mail: iskhaq.iskandar@xxxxxxxxx http://iskhaq.wordpress.com/ ----------------------------------------------------------------