Useful Tools: Difference between revisions

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Of course, 44 seconds v 4 seconds isn't much (and with smaller files, GPFS can sometimes 'cache' the files making it seem fast), but with c360, things get inflated:

=== Extract ~~variable~~(s) from a file ===

=== Extract fields(s) from a file ===

Often, our NetCDF4 files have many variables and we only care about one. CDO allows one to extract or ''select'' one or more variables:

Often, our NetCDF4 files have many variables and we only care about one. CDO allows one to extract or ''select'' one or more variables. For example, if you only want CLCN, use '''selname''':

$ cdo '''selname,CLCN''' mat-WW3-G40U-2013Jun10-NOWAVE-1day-c48.geosgcm_moist.20000415_0900z.nc4 onlyclcn.nc4

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2000-04-15 09:00:00

cdo sinfon: Processed 1 variable over 1 timestep ( 0.00s )

CDO has many of these operators:

selparam Select parameters by identifier

delparam Delete parameters by identifier

selcode Select parameters by code number

delcode Delete parameters by code number

selname Select parameters by name

delname Delete parameters by name

selstdname Select parameters by standard name

sellevel Select levels

sellevidx Select levels by index

selgrid Select grids

selzaxis Select z-axes

selltype Select GRIB level types

seltabnum Select parameter table numbers

seltimestep Select timesteps

seltime Select times

selhour Select hours

selday Select days

selmon Select months

selyear Select years

selseas Select seasons

seldate Select dates

selsmon Select single month

sellonlatbox Select a longitude/latitude box

selindexbox Select an index box

=== Extract time(s) from a file ===

@@ Line 141: / Line 141: @@
 Of course, 44 seconds v 4 seconds isn't much (and with smaller files, GPFS can sometimes 'cache' the files making it seem fast), but with c360, things get inflated:
-=== Extract variable(s) from a file ===
+=== Extract fields(s) from a file ===
-Often, our NetCDF4 files have many variables and we only care about one. CDO allows one to extract or ''select'' one or more variables:
+Often, our NetCDF4 files have many variables and we only care about one. CDO allows one to extract or ''select'' one or more variables. For example, if you only want CLCN, use '''selname''':
   $ cdo '''selname,CLCN''' mat-WW3-G40U-2013Jun10-NOWAVE-1day-c48.geosgcm_moist.20000415_0900z.nc4 onlyclcn.nc4
@@ Line 167: / Line 167: @@
 -04-15 09:00:00
   cdo sinfon: Processed 1 variable over 1 timestep ( 0.00s )
+CDO has many of these operators:
+  selparam	 Select parameters by identifier
+  delparam	 Delete parameters by identifier
+  selcode	 Select parameters by code number
+  delcode	 Delete parameters by code number
+  selname	 Select parameters by name
+  delname	 Delete parameters by name
+  selstdname	 Select parameters by standard name
+  sellevel	 Select levels
+  sellevidx	 Select levels by index
+  selgrid	 Select grids
+  selzaxis	 Select z-axes
+  selltype	 Select GRIB level types
+  seltabnum	 Select parameter table numbers
+  seltimestep	 Select timesteps
+  seltime	 Select times
+  selhour	 Select hours
+  selday 	 Select days
+  selmon 	 Select months
+  selyear	 Select years
+  selseas	 Select seasons
+  seldate	 Select dates
+  selsmon	 Select single month
+  sellonlatbox	 Select a longitude/latitude box
+  selindexbox	 Select an index box
 === Extract time(s) from a file ===