CDO

Hi,

can i extract the position (lon/lat) of a gridcell with cdo?

I'm not sure if I understood your question correctly. For all grid/cells (assuming your input file has only one variable and one level; otherwise you have to include -selvar and -sellevel)

cdo -outputcenter input_file.grb > outfile.dat

This will give all lon/lat and corresponding value

"-outputbounds" also can be used instead of -outputcenter

If you are looking for the exact lat/lon (for example nearby 68 lon and -18 lat), you may try:

cdo -outputcenter -remapnn,lon=-68_lat=-18 input_file.grb

Cheers,
Jaison.

ok, thanks for this hint! ;-)

i have a nc file with monthly-mean-temperature over one year period!
with

cdo outputf,'%10.2f',2700 input > output

i get a list with values

    293.42    293.46    293.14    293.69    ...
    283.42    294.46    296.14    299.69    ...
      .         .         .         .       ...
      .         .         .         .       ...
      .         .         .         .       ...
    243.42    273.46    293.04    283.69    ...

12 rows with 2700 values each.

ist it possible to combine outputcenter with outputf?

i would like to have

    293.42(LAT/LON)    293.46(LAT/LON)    293.14(LAT/LON)    293.69(LAT/LON)    ...

or

    ROW 1     ROW 2     ROW 3     ROW 4     ...
    LAT       LAT       LAT       LAT       ...                          
    LON       LON       LON       LON       ...
    293.42    293.46    293.14    293.69    ...

as an example of formatting.

is it possible with cdo?

Hi,

I don't think there is an option in CDO to format "outputcenter"; otherwise you could use the shell commands like sed and awk;

for example;

cdo -outputcenter ifile.nc | sed '/^ #/d;s/#.*//' > colums_out.dat

this will remove the header and

awk '{ for (i=1;i<=NF;i++) { arr[i]=arr[i]" "$i; }} END{ for(i=1;i<=NF;i++) print arr[i]; }' colums_out.dat > rows_out.dat

the above will transform the column data to rows.

May be others can help you with more intuitive ways

Cheers,
J.

Hi,

thanks for your help!

I suspect that it boils down to awk and sed... ;-)

The Regular expression did not remove the header.

Can you explain the regular expression in sed, i'm not very familiar with this at the moment...

Cheers,
Ronny

Try the undocumented operator outputtab to create a user defined table of a dataset:
Each parameter of outputtab is one row in the table. Here is an example to print the Lon, Lat and Value of all fields:

cdo outputtab,lon,lat,value ifile

value, code, name, lon, lat, lev, date, time, year, month, day

The Regular expression did not remove the header.

It will work BUT if you simply copy the expression (using mouse) it may not work since there is NO space between ^ and # in the first part of the sed expression; if there is a space character it won't work. It must be /^#/d

Anyway thanks to Uwe for the "outputtab" info.

Cheers,
J.

Thanks for your great tips!
That helps me alot and i can mix that with sed and awk!

Cheers,
Ronny

Hi,
I have a spatio-temporal dataset. I need the time series of the specific grid point (for example -44 lon and -20 lat, from 01/01/2009 to 31/12/2009).
How can I do this?
I've been tried this functions:
cdo -outputcenter -remapnn,lon=-68_lat=-18 input_file.grb (but just worked with the first hour/day).
and
cdo outputtab,date,lon,lat,value ifile (but extract all grid points and I need only one)

Can anybody help me?

best regards,

Romulo

Hi,

I've been tried this functions:
cdo -outputcenter -remapnn,lon=-68_lat=-18 input_file.grb (but just worked with the first hour/day).

try "outputtab" along with remapnn (instead of outputcenter"); i.e.

cdo -outputtab,date,lon,lat,value -remapnn,lon=-68_lat=-18 input_file.grb

Cheers,
J.

Hi J.,
Thank you very much for the help!
exactly how I wanted.

cheers,
Romulo

Hi, I am following up this topic, I need to get one value for all the grids (e.g. region), Is that a command to calculate this? I tried cdo zonmean but it generate a value for each longitude? Can someone here help me out?
Regards,

Ping

fldmean computes the mean value over all grid cells.

Hi Jaison,
Could you help me to write as below formatting :

ID 1x1     ID 1x2     ID 1x3     ID 1x4     ...
             LAT        LAT         LAT         LAT       ...                          
 TIME         LON        LON         LON        LON       ...
20140101      1.1       4.6       5.2          5.6        ...         
20140102      5.8       5.8       9.6          2.5        ...
.
.
.
and I would like to get one value for each grid (computes the annual mean value).
I am looking forward your answering.
Thanks so much.  
Jaison-Thomas Ambadan wrote:

Hi,

I don't think there is an option in CDO to format "outputcenter"; otherwise you could use the shell commands like sed and awk;

for example;

cdo -outputcenter ifile.nc | sed '/^ #/d;s/#.*//' > colums_out.dat

this will remove the header and

awk '{ for (i=1;i<=NF;i++) { arr[i]=arr[i]" "$i; }} END{ for(i=1;i<=NF;i++) print arr[i]; }' colums_out.dat > rows_out.dat

the above will transform the column data to rows.

May be others can help you with more intuitive ways

Cheers,
J.

I would recommend using:

cdo -outputtab,date,time,lon > ifile.dat

then load the ifile.dat to some software like matlab/R and then do a transpose()

if you want to use shell, then use the awk loop mentioned above to transpose into rows

Hi all,
I need help with outputtab, I'm using version cdo 1.6 for windows, I have problemos when I want to save the result in a table data.tab and I get this error:
cdo outputtab: Open failed on >> <
Invalid argument

My line of code is:
cdo -outputtab,year,month,lon,lat,value -remapnn,lon=76_lat=3 data.nc > data.tab

Appreciate your help