bmp2nc

#!/usr/bin/env python

import netCDF4 as nc
from  PIL import Image
import numpy as np
from argparse import ArgumentParser


def write_field(filename, data):
    file=nc.Dataset(filename,"w")
    file.createDimension("y",data.shape[0])
    file.createDimension("x",data.shape[1])
    file.createVariable("imagedata",'i4',("y","x"))
    file.variables["imagedata"][:]=data


# def rescale_data(data, prescale_function=False):
#     if prescale_function:
#         data=prescale_function(data)
#     dmin = data.min()
#     dmax = data.max()
#     data = ((data+dmin)/(dmax-dmin)*255).round().astype(np.uint8)
#     return data

def read_image(filename, opts=False):
    pic = Image.open(filename)
    pix = np.asarray(pic) # .reshape(pic.size[0], pic.size[1], 3)
    if len(pix.shape) == 3:
        pix= pix[:,:,0]*(256*256)+pix[:,:,1]*256+pix[:,:,2]
    # values=np.unique(pix)
    # pix2=np.zeros(pix.shape,dtype='i8')
    # for (n,x) in enumerate (values):
    #     pix2[pix==x]=n
    # return pix2
    return pix


def parse_options():
    # initialize parser
    parser = ArgumentParser()
    parser.description = "Convert a netcdf field into a bmp image"
    # specify options
    parser.add_argument("-f" , "--filename", help = "filename", required = True)
    parser.add_argument("-t" , "--transpose", help = "transpose field", action = "store_true")
#    parser.add_argument("-n" , "--var_name", help = "variable name", required = True)
    parser.add_argument("-o" , "--out_name", help = "filename for output, default file.nc for input name file.bmp ", default = None )
    parser.add_argument("-v", "--verbose", 
                        help='''Be verbose''', action="store_true")
    
    # run argparse
    options = parser.parse_args()
    return options  


def main():
    options = parse_options()
    data = read_image(options.filename, opts=False)
    outfilename = options.filename[:-4]+".nc"
    if options.out_name:
        outfilename = options.out_name
    if options.transpose:
        data=data.transpose()
    write_field(outfilename,  data)
if __name__ == "__main__":
    main()