Expr(f) and Z-axis
Added by Thomas Lechauve over 8 years ago
Hi,
I did not found any expr command to select a specific z-axis of a variable.
For example, i have isobaric and surface vertical coordinates and inside isobaric i have 31 levels. i would like to select isobaric(29), but how ?
Cheers,
Replies (4)
RE: Expr(f) and Z-axis - Added by Uwe Schulzweida over 8 years ago
You can select the vertical coordinate of a variable with clev(x). The value of one vertical layer can be selected with sellevidx(x,29). Here is an example:
vcoord=clev(varname); vcoord29=sellevidx(vcoord,29);Or in one line:
vcoord29=sellevidx(clev(varname),29);Unfortunately all expr command with a comma (like sellevidx(x,k)) can't be processed from the CDO command line. That means they can be used only with the CDO operator exprf or aexprf, which read the expr commands from a file.
Cheers,
Uwe
RE: Expr(f) and Z-axis - Added by Thomas Lechauve over 8 years ago
Hi,
Thanks for you answer, but i think i did not ask the proper question. Put the levels aside
Here the sinfon output of my dataset:
File format : GRIB2 -1 : Institut Source Steptype Levels Num Points Num Dtype : Parameter name 1 : NCEP unknown avg 1 1 259920 1 P9 : tcc 2 : NCEP unknown avg 1 2 259920 1 P9 : tcc 3 : NCEP unknown avg 1 3 259920 1 P9 : tcc Grid coordinates : 1 : lonlat : points=259920 (720x361) lon : 0 to 359.5 by 0.5 degrees_east circular lat : 90 to -90 by -0.5 degrees_north Vertical coordinates : 1 : generic (ltype=214) : : levels=1 lev : 0 2 : generic (ltype=224) : : levels=1 lev : 0 3 : generic (ltype=234) : : levels=1 lev : 0 Time coordinate : 2 steps RefTime = 2016-09-23 12:00:00 Units = hours Calendar = proleptic_gregorian YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss YYYY-MM-DD hh:mm:ss 2016-09-23 15:00:00 2016-09-23 18:00:00
Here an example of what i want:
tcc214 = ? tcc224 = ? tcc234 = ?
As all variables have the same name, i can not use clev(tcc).
Thank you in advance
Cheers,
RE: Expr(f) and Z-axis - Added by Uwe Schulzweida over 8 years ago
Duplicate variable names can't be handled by the CDO operator expr. The last occurrence of the variable name will be used.
Variables with different level type (ltype) can only be selected with the CDO operator selltype:
cdo selltype,214 file ofile214
RE: Expr(f) and Z-axis - Added by Thomas Lechauve over 8 years ago
Thank you, then i'll use temp files.