Problem on subsampling gridded field onto point data locations and times

[Yang Haijun <navyang@xxxxxxxxxxxxxxxxxxxx>]

Hi, all,

I am learning to subsampling gridded field onto point data times. I did the following thing 
based on Ferret documentation(V5.0) in the chapter entitled "Chapter 7A: WORKING WITH SPECIAL 
DATA SETS" section 2.3:

yes? use coads_climatology
yes? let my_lon=lon[d=my_data_file.dat]
yes? let my_lat=lat[d=my_data_file.dat]
yes? let sst_xy=samplexy(sst,my_lon,my_lat)

The file "my_data_file.dat" is

    index  longitude  latitude
      1       150         0
      2       150        2.5
      3       150         5
      4       150        7.5
      5       150        10
      6       157.5      12.5
      7       165        15
      8       172.5      17.5
      9       180        20
     10       187.5      22.5
     11       195        25
     12       202.5      27.5
     13       210        30

So "my_lon" and "my_lat" are respectively,

    150,150,150,150,150,157.7,165,172.5,180,187.5,195,202.5,210
     
      0,2.5,  5,7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30
      
The variable sst_xy should have a 2-D structure with index by 12 months.

But when I list sst_xy, it gives

yes? list sst_xy
             SAMPLEXY(SST,MY_LON,MY_LAT)
             DATA SET: /usr5/navyang/FERRET/FER_DSETS/data/coads_climatology.cdf
                    1   2   3   4   5   6   7   8   9   10  11  12  13  
                     1   2   3   4   5   6   7   8   9  10  11  12  13
 16-JAN      /  1:....................................................
 15-FEB      /  2:....................................................
 17-MAR      /  3:....................................................
 16-APR      /  4:....................................................
 16-MAY      /  5:....................................................
 16-JUN      /  6:....................................................
 16-JUL      /  7:....................................................
 16-AUG      /  8:....................................................
 15-SEP      /  9:....................................................
 16-OCT      / 10:....................................................
 15-NOV      / 11:....................................................
 16-DEC      / 12:....................................................


Can anyone tell me what's wrong with the aboved process?

Thanks a lot in advance.

Haijun Yang


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Dept. of Atmospheric and Oceanic Sci.
Univ. of Wisconsin-Madison
1225 West Dayton St.
Madison, WI 53706
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