Translating multiband netCDF to GTiff using gdalwarp and Python

Question

How do I translate (extract) multiband netCDF to individual raster geotiff?

I am new to scripting, so I am hoping you could help me with how I should write my gdal translate script starting from setting my working directory.

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Instructions that come with the data:

The maps can be transformed to the GTiff format using GDAL as follows, replacing Year, Band_Name and Output_Filename with the parameters of interest:

gdalwarp -of Gtiff -co COMPRESS=LZW -co TILED=YES -ot Byte -te -180.0000000 -90.0000000 180.0000000 90.0000000 -tr 0.002777777777778 0.002777777777778 -t_srs EPSG:4326 NETCDF:xxxYEAR.nc:BandName OutputFilename.tif

So far:

import os, sys # the standard imports

BaseFolder = r'C:\Users\Dlan\Desktop\netCDF_TIFF' # change this to match your data

for FullPath, dirs, files in os.walk(BaseFolder):
for ThisFile in files:                   # iterate the files
    fN,fE = os.path.splitext(ThisFile)   # separate file name and extension
    if fE.lower() == 'LCCS-2018.nc':
        # this is a netCDF file, though other extensions might exist
        # you will need to provide these details or ascertain them from
        # the input NetCDF file name.

        Year = '2018'
        Band = 'lccs_class'
        OutputName = 'LCCS-2018'


        GDAL_Command = 'gdalwarp -of Gtiff -co COMPRESS=LZW -co TILED=YES -ot Byte -te '\
                                     '-180.0000000 -90.0000000 180.0000000 90.0000000 -tr 0.002777777777778 0.002777777777778 '\
                                     '-t_srs EPSG:4326 NETCDF:{}YEAR.nc:{} {}.tif'.format( Year, Band, os.path.join(FullPath,OutputName))
        os.system(GDAL_Command) # run the command

There are some other instructions:

The maps can be transformed to the GTiff format using GDAL as follows, replacing Year, Band_Name and Output_Filename with the parameters of interest:

with Year the year : 2016, 2017 or 2018; and BandName one of the following: lccs_class; processed_flag; current_pixel_state; observation_count; change_count.

Format: gdalwarp -of Gtiff -co COMPRESS=LZW -co TILED=YES -ot Byte -te -180.0000000 -90.0000000 180.0000000 90.0000000 -tr 0.002777777777778 0.002777777777778 -t_srs EPSG:4326 NETCDF:XXX-YEAR.nc:BandName OutputFilename.tif

Example code: gdalwarp -of Gtiff -co COMPRESS=LZW -co TILED=YES -ot Byte -te -180.0000000 -90.0000000 180.0000000 90.0000000 -tr 0.002777777777778 0.002777777777778 -t_srs EPSG:4326 NETCDF:LCCS-2018.nc:lccs_class LCCS-2018.tif

Answer 1

It can be achieved with a simple walk or listdir:

import os, sys # the standard imports

BaseFolder = r'c:\your\folder\with\data' # change this to match your data

for FullPath, dirs, files in os.walk(BaseFolder):
    for ThisFile in files:                   # iterate the files
        fN,fE = os.path.splitext(ThisFile)   # separate file name and extension
        if fE.lower() == '.nc':
            # this is a netCDF file, though other extensions might exist
            # you will need to provide these details or ascertain them from
            # the input NetCDF file name.
            Year = 'XXXX'
            Band = 'bandName'
            OutputName = 'OutputName.tif'

            GDAL_Command = 'gdalwarp -of Gtiff -co COMPRESS=LZW -co TILED=YES -ot Byte -te '\
                                         '-180.0000000 -90.0000000 180.0000000 90.0000000 -tr 0.002777777777778 0.002777777777778 '\
                                         '-t_srs EPSG:4326 NETCDF:{}YEAR.nc:{} {}.tif'.format( Year, Band, os.path.join(FullPath,OutputName))
            os.system(GDAL_Command) # run the command 

Hopefully you can derive your output name from your input, I don't have enough information to decide that but this will help loop through the folders and run the command when you have decided what the command should contain. Note the '\ on the end of each line is a continuation character to split the sting onto multiple lines for readability.

Before you can start with the coding portion of this you need to have your warp command recognized. If you don't have OSGeo4W shell there is a shell batch in your GDAL install folder or you could navigate to your GDAL\bin folder with a command like CD /D "C:\Program Files\GDAL" where the gdalwarp executable resides.