How to create a json file with the names and attributes of a VIIRS L2 CLDPROP netcdf file using python 3 ?

Example of python 3 code to save in a json file the names and attributes of a VIIRS L2 CLDPROP netcdf file.

Table of contents

Read the file
Get all group names
Get names and attributes in each group
Save in a json file
Python script
References

Note: the json file created can be found here

Read the file

import netCDF4
import numpy as np
import json
import pprint

f = netCDF4.Dataset('CLDPROP_L2_VIIRS_SNPP.A2018046.1436.001.2019068074007.nc')

Get all group names

group_dic = f.groups.keys()

Get names and attributes in each group

data_json = {}

for group in group_dic:
    selected_group = f.groups[group]
    group_variables_dic = selected_group.variables.keys()
    data_group_json = {}
    for group_variables in group_variables_dic:
        attributes = selected_group.variables[group_variables]
        #----------#
        # Get variables attributes
        attributes_dic = {}
        try:
            if group == 'scan_line_attributes':
                attributes_dic['long_name'] = attributes.long_name
                attributes_dic['FillValue'] = int( attributes._FillValue )
                attributes_dic['valid_min'] = int( attributes.valid_min )
                attributes_dic['valid_max'] = int( attributes.valid_max )
                attributes_dic['units'] = attributes.units
                attributes_dic['shape'] = attributes.shape          
            if group == 'geolocation_data':
                attributes_dic['long_name'] = attributes.long_name
                attributes_dic['FillValue'] = int( attributes._FillValue )
                attributes_dic['valid_min'] = int( attributes.valid_min )
                attributes_dic['valid_max'] = int( attributes.valid_max )
                attributes_dic['units'] = attributes.units
                attributes_dic['shape'] = attributes.shape  
                attributes_dic['scale_factor'] = attributes.scale_factor
                attributes_dic['add_offset'] = attributes.add_offset
            if group == 'geophysical_data':
                attributes_dic['long_name'] = attributes.long_name
                attributes_dic['FillValue'] = int( attributes._FillValue )
                attributes_dic['valid_min'] = int( attributes.valid_min )
                attributes_dic['valid_max'] = int( attributes.valid_max )
                attributes_dic['scale_factor'] = attributes.scale_factor
                attributes_dic['add_offset'] = attributes.add_offset
                attributes_dic['units'] = attributes.units
                attributes_dic['shape'] = attributes.shape  
            if group == 'cloud_model_data':
                attributes_dic['long_name'] = attributes.long_name
                attributes_dic['FillValue'] = int( attributes._FillValue )
                attributes_dic['valid_min'] = int( attributes.valid_min )
                attributes_dic['valid_max'] = int( attributes.valid_max )
                attributes_dic['units'] = attributes.units
                attributes_dic['shape'] = attributes.shape  
                attributes_dic['description01'] = attributes.description01  
                attributes_dic['description02'] = attributes.description02  
                attributes_dic['description03'] = attributes.description03  
                attributes_dic['description04'] = attributes.description04  
                attributes_dic['description05'] = attributes.description05  
                attributes_dic['description06'] = attributes.description06                  
        except:
            pass

        data_group_json[group_variables] = attributes_dic

    data_json[group] = data_group_json

Save in a json file

with open('viirs_cldprop_l2_names_attributes.json', 'w') as fp:
    json.dump(data_json, fp, sort_keys=False, indent=4)

Python script

import netCDF4
import numpy as np
import json
import pprint

#----------------------------------------------------------------------------------------#
# Read file

f = netCDF4.Dataset('CLDPROP_L2_VIIRS_SNPP.A2018046.1436.001.2019068074007.nc')

#----------------------------------------------------------------------------------------#
# Read group names

group_dic = f.groups.keys()

#----------------------------------------------------------------------------------------#
# Get names and attributes in each group

data_json = {}

for group in group_dic:
    selected_group = f.groups[group]
    group_variables_dic = selected_group.variables.keys()
    data_group_json = {}
    for group_variables in group_variables_dic:
        attributes = selected_group.variables[group_variables]
        #----------#
        # Get variables attributes
        attributes_dic = {}
        try:
            if group == 'scan_line_attributes':
                attributes_dic['long_name'] = attributes.long_name
                attributes_dic['FillValue'] = int( attributes._FillValue )
                attributes_dic['valid_min'] = int( attributes.valid_min )
                attributes_dic['valid_max'] = int( attributes.valid_max )
                attributes_dic['units'] = attributes.units
                attributes_dic['shape'] = attributes.shape          
            if group == 'geolocation_data':
                attributes_dic['long_name'] = attributes.long_name
                attributes_dic['FillValue'] = int( attributes._FillValue )
                attributes_dic['valid_min'] = int( attributes.valid_min )
                attributes_dic['valid_max'] = int( attributes.valid_max )
                attributes_dic['units'] = attributes.units
                attributes_dic['shape'] = attributes.shape  
                attributes_dic['scale_factor'] = attributes.scale_factor
                attributes_dic['add_offset'] = attributes.add_offset
            if group == 'geophysical_data':
                attributes_dic['long_name'] = attributes.long_name
                attributes_dic['FillValue'] = int( attributes._FillValue )
                attributes_dic['valid_min'] = int( attributes.valid_min )
                attributes_dic['valid_max'] = int( attributes.valid_max )
                attributes_dic['scale_factor'] = attributes.scale_factor
                attributes_dic['add_offset'] = attributes.add_offset
                attributes_dic['units'] = attributes.units
                attributes_dic['shape'] = attributes.shape  
            if group == 'cloud_model_data':
                attributes_dic['long_name'] = attributes.long_name
                attributes_dic['FillValue'] = int( attributes._FillValue )
                attributes_dic['valid_min'] = int( attributes.valid_min )
                attributes_dic['valid_max'] = int( attributes.valid_max )
                attributes_dic['units'] = attributes.units
                attributes_dic['shape'] = attributes.shape  
                attributes_dic['description01'] = attributes.description01  
                attributes_dic['description02'] = attributes.description02  
                attributes_dic['description03'] = attributes.description03  
                attributes_dic['description04'] = attributes.description04  
                attributes_dic['description05'] = attributes.description05  
                attributes_dic['description06'] = attributes.description06                  
        except:
            pass

        data_group_json[group_variables] = attributes_dic

    data_json[group] = data_group_json


#----------------------------------------------------------------------------------------#
# Save in a json file

with open('viirs_cldprop_l2_names_attributes.json', 'w') as fp:
    json.dump(data_json, fp, sort_keys=False, indent=4)

References

Link	WebSite
netCDF4 module	unidata.github.io
Continuity MODIS-VIIRS Cloud Properties products available	ladsweb.modaps.eosdis.nasa.gov
Search for Product Files	ladsweb.modaps.eosdis.nasa.gov
CLDPROP_L2_VIIRS_SNPP - VIIRS/Suomi-NPP Cloud Properties	ladsweb.modaps.eosdis.nasa.gov
READING NETCDF4 DATA IN PYTHON	iescoders.com
Reading NetCDF files with Python	ceda.ac.uk
MODIS and VIIRS Cloud Properties: User Guide	modis-atmosphere.gsfc.nasa.gov
Continuity User Guides	modis-atmosphere.gsfc.nasa.gov
pprint	python doc
How to Get a List of Class Attributes in Python	blog.pythonlibrary.org

Developer in my spare time, I’m interested in Earth observation and satellite-based fire detection. Passionate about Python, machine learning, and open science.