EXPNDI_BY_Z

EXPNDI_BY_Z(dat,mask,n_profiles,max_profile_len)

Use to split a variable into a set of depth profiles (see also the EXPNDI_BY_T function for T profiles)

Example:
Data read from ascii files or data organized as simple 1-D lists may represent sets of depth profiles, but of different lengths. See how DEPTH starts with 0 for each station, but there are a different number of measurements in each profile.

STATION DEPTH LON LAT TEMP SALINITY1 0 12.45 45.5 24.25 36.421 5 12.45 45.5 24.46 36.421 10 12.45 45.5 24.23 36.433 0 15.08 51.3 24.74 36.062 5 15.08 51.3 24.65 36.052 10 15.08 51.3 24.74 362 20 15.08 51.3 24.75 35.982 50 15.08 51.3 24.75 35.952 75 15.08 51.3 24.75 35.952 100 15.08 51.3 24.75 35.963 0 17.11 41.3 24.79 36.343 5 17.11 41.3 24.8 36.343 10 17.11 41.3 24.79 36.353 20 17.11 41.3 24.78 36.343 50 17.11 41.3 24.78 36.313 75 17.11 41.3 24.78 36.33 100 17.11 41.3 24.77 36.313 150 17.11 41.3 24.78 36.323 200 17.11 41.3 25.1 36.273 300 17.11 41.3 24.56 36.243 400 17.11 41.3 24.81 36.33 600 17.11 41.3 24.8 36.31

Open this dataset. Read the data as single 1-D lists, then define a XT variable.

yes? define axis/x=1:22:1 xinyes? define grid/x=xin input_gridyes? file/skip=1/var="sta, depth, lat, lon, temp, salt"/grid=input_grid tprofiles.datyes? list depth, temp, salt
 DATA SET: ./zprofiles.dat
 X: 0.5 to 22.5
 Column 1: DEPTH
 Column 2: TEMP
 Column 3: SALT
 DEPTH TEMP SALT
1 / 1: 0.0 24.25 36.42
2 / 2: 5.0 24.46 36.42
3 / 3: 10.0 24.23 36.43
4 / 4: 0.0 24.74 36.06
5 / 5: 5.0 24.65 36.05
6 / 6: 10.0 24.74 36.00
7 / 7: 20.0 24.75 35.98
8 / 8: 50.0 24.75 35.95
9 / 9: 75.0 24.75 35.95
10 / 10: 100.0 24.75 35.96
11 / 11: 0.0 24.79 36.34
12 / 12: 5.0 24.80 36.34
13 / 13: 10.0 24.79 36.35
14 / 14: 20.0 24.78 36.34
15 / 15: 50.0 24.78 36.31
16 / 16: 75.0 24.78 36.30
17 / 17: 100.0 24.77 36.31
18 / 18: 150.0 24.78 36.32
19 / 19: 200.0 25.10 36.27
20 / 20: 300.0 24.56 36.24
21 / 21: 400.0 24.81 36.30
22 / 22: 600.0 24.80 36.31
...! Define the mask variable so that each new station is marked with a 1.! (We could also have said "let mask = if depth EQ 0 then 1")yes? let mask = if depth[i=@ddb] LT 0 then 1yes? list depth, mask
 DATA SET: ./zprofiles.dat
 X: 0.5 to 22.5
 Column 1: DEPTH
 Column 2: MASK is IF DEPTH[I=@DDB] LT 0 THEN 1
 DEPTH MASK
1 / 1: 0.0 ....
2 / 2: 5.0 ....
3 / 3: 10.0 ....
4 / 4: 0.0 1.000
5 / 5: 5.0 ....
6 / 6: 10.0 ....
7 / 7: 20.0 ....
8 / 8: 50.0 ....
9 / 9: 75.0 ....
10 / 10: 100.0 ....
11 / 11: 0.0 1.000
12 / 12: 5.0 ....
13 / 13: 10.0 ....
14 / 14: 20.0 ....
15 / 15: 50.0 ....
16 / 16: 75.0 ....
17 / 17: 100.0 ....
18 / 18: 150.0 ....
19 / 19: 200.0 ....
20 / 20: 300.0 ....
21 / 21: 400.0 ....
22 / 22: 600.0 ....
! Note that the first is profile is not marked in the mask.yes? let n_profiles = `1 + mask[i=@ngd]`! We may be able to define the size of the profile using the data, ! Depending on the information available to us. Or just give some upper bound.

yes? let max_profile_len = 15yes? let sal_xz = expndi_by_z(salt, mask, n_profiles, max_profile_len)yes? list sal_xz
 VARIABLE : EXPNDI_BY_Z(SALT, MASK, N_PROFILES, MAX_PROFILE_LEN)
 FILENAME : zprofiles.dat
 SUBSET : 3 by 15 points (X-Z)
 1 2 3 
 1 2 3
 1 / 1: 36.42 36.06 36.34
 2 / 2: 36.42 36.05 36.34
 3 / 3: 36.43 36.00 36.35
 4 / 4: .... 35.98 36.34
 5 / 5: .... 35.95 36.31
 6 / 6: .... 35.95 36.30
 7 / 7: .... 35.96 36.31
 8 / 8: .... .... 36.32
 9 / 9: .... .... 36.27
 10 / 10: .... .... 36.24
 11 / 11: .... .... 36.30
 12 / 12: .... .... 36.31
 13 / 13: .... .... ....
 14 / 14: .... .... ....
 15 / 15: .... .... ....

Now we could define a Z axis in units of meters, using the data in variable DEPTH, and regrid variable sal_xz to that axis using the @ASN transformation. We could also go on to use the information in the file to locate the profiles in X and Y.