Hi Adir,

The easiest way to extract a variable at a given point from a netCDF file is by using the NCO tools (free software), the command you need is (ncks):

ncks -v u10max,v10max -d lon,145.7292 -d lat,-40.9972 infile.nc outfile.nc

here I am extracting variables 'u10max' and 'v10max' from the point (145.7292,-40.9972) from the file 'infile.nc' and writing them to the file 'outfile.nc' (for a list of all the commands in NCO see: http://nco.sourceforge.net/#Definition)

You can convert any netCDF file to plain text (*.txt) using the command:

ncdump infile.nc > outfile.txt

Hope it helps,

Augusto

Hi Adir,

The easiest way to extract a variable at a given point from a netCDF file is by using the NCO tools (free software), the command you need is (ncks):

ncks -v u10max,v10max -d lon,145.7292 -d lat,-40.9972 infile.nc outfile.nc

here I am extracting variables 'u10max' and 'v10max' from the point (145.7292,-40.9972) from the file 'infile.nc' and writing them to the file 'outfile.nc' (for a list of all the commands in NCO see: http://nco.sourceforge.net/#Definition)

You can convert any netCDF file to plain text (*.txt) using the command:

ncdump infile.nc > outfile.txt

Hope it helps,

Augusto

Dear Hadir;

Your question is a very common question, so I suggest you to read these links, which could help you, but if you need any more help I am here.

https://www.researchgate.net/post/How_can_I_extract_a_time_series_of_the_SM_data_for_a_specific_location_specific_longitude_and_latitude_from_a_SMAP_h5_dataset_or_tif

https://www.researchgate.net/post/How_can_I_open_and_read_TRMM_NetCDF_file_in_R_or_Matlab

https://www.researchgate.net/post/How_to_Read_3BR42_RT_in_R_or_Matlab

https://www.researchgate.net/post/Projection_of_NetCDF_file_for_the_extraction_of_climate_change_variables

https://www.researchgate.net/post/Why_do_I_get_different_values_when_I_extract_climate_data_from_netCDF_files_using_Matlab_and_ArcGIS_for_the_same_grid_point

https://www.researchgate.net/post/Does_anybody_know_a_visualization_software_for_viewing_velocity_vectors_and_flooding_based_on_netcdf_format

Also you could use different software as the link shows:

https://www.esrl.noaa.gov/psd/data/gridded/tools.html

Although Matlab is easy to use, but my suggestion is using NCL. I send you the user guide and Tutorial of that.

Best

use cdo

You can use either NCO or CDO, which both are both a collection of command line tools to post-process NetCDF files.

CDO is developed by Max-Planck Institute in Hamburg, Germany mainly for use with Meteorological data, though can be used for other data too.

https://code.mpimet.mpg.de/projects/cdo

It uses a larger number of operators with different names, which takes time to memorize but there's a neat reference card:

https://code.mpimet.mpg.de/projects/cdo/embedded/cdo_refcard.pdf

NCO is an open source project and widely used in the US. It has a collection of about a dozen packages, which can be used for different operations incl. cutting .nc files.

http://nco.sourceforge.net/

You may look at both and decide, which one works best for you.

I would recommend NCL. Using ncl you can extract particular bounding box, and save that output to a txt file. Sample code is attached inside.

Thank you for your concern. But does NCL work in window or it is only in Linux system.

.

It's depend on your model. What is your model? What is domain and scale of your model?

You can read data from netcdf file by using Netcdf Extractor in https://agrimetsoft.com/netcdf-extractor.aspx

It's a windows software for extract time series from netcdf files.

But about calculate your grid number, it's depend on your model. If you have domain of your netcdf file you can use 'Grid Number Calculator' Api that there is in Netcdf-Extractor V1.1 or higher.

Besides that, you can watch many video about calculation of grid number(origin and shape) in my Chanel in YouTube

https://www.youtube.com/playlist?list=PLaT4Cfntnc9jklkHwIh0tR0eGx_3BDc0k

or visit http://faq.agrimetsoft.com

Thanks all for help.

Hi

You can use a tool with name "Open NC File" for extract data by using Lat/Lon in decimal or UTM for this purpose.

I can't write the link of my website please search "Open NC File" in google to find it.

You can use MATLAB (ncdisp, ncread, ....)

https://www.mathworks.com/help/matlab/ref/ncread.html

after you sure about your model you can use code like this in Matlab.

the details is depend on your model.

Add a folder named AOI

with shape file of your area of interest and nic file in other folder code is simple just take a look.

If face any problem tell me.

Hi dear

You can use below script in NCL. You must specify the latitude and longitude you are looking for. Provides data as csv format.

Hadir A. Moneim , If you are familiar to R you can extract your data with a few statements.

First install and load "raster" and "ncdf4" packages

# read in our netcdf file

ncfile

I use the FERRET tool in the Linux operating system. You can read at a point you choose.

Dear Hadir,

The best tool to extract data from netCDF is python programming. You can extract the data from many netCDF files using for loop in python but I think the simple tools are GIS softwares like QGIS and ARCGIS.

Hi dear all

As other researchers have mentioned above, you can use different programming codes and software tools, namely Matlab coding, NCL, ArcGIS, R, and GRADS.

But the most important tips that you should consider is:

If you want to extract your data model in monthly scale and in a continuous file, it is not any easy process. I want to present an example, as you know CMIP5 has around 60 models which every of them has a especial format for downloading data. One of them in 10 years continuous file but other not.

I mean that if you want to write a unique code which can apply for every format of file (in NC) it is not possible to do. If you want to overcome to this critical issue you should have enough knowledge about programming languages with different aspects.

However, I want to tell you that it was a big problem for my and my colleagues since we are working on various projects that the input files are in nc, nc4, and etc.

So, we decided to solve it and progress a complete tool which can extract any format of nc files, such ac CMIP5 models, CORDEX data outputs, and different outputs in nc. Please see the bellow link for better clarifications:

https://agrimetsoft.com/open_nc_file_for_coordinates.aspx

With this tool, you can easily enter your lists of stations and extract them in a while without any concern, and reduce your time. See the link for better understanding.

Kindest Regards,

Nasrin

Bonjour,

J'ai le même problème actuellement et je tente d'utiliser cdo; mais la solution de

Muhammad Mubashar Dogar, permet d'extraire une zone et non un point. Comment faire pour extraire les données en un point d'un fichier netcdf avec cdo?

Merci.

lat=ncread(fileName,'lat');

if lat is in sub groups, then

lat=ncread(fileName,'/groups/lat');

ncks from nco should work