Python script to grab modus data

modis.py

#===============================================================================
#  Date:    	May 22, 2016
#  Author:  	Lindy Nelson
#  Purpose: 	This script downloads monthly MODIS burn data from 
#  
#
#  FTP Server:  fuoco.geog.umd.edu
#  
#
#  Python FTP User Guide:
#
#				https://docs.python.org/2.7/library/ftplib.html
#
#  Modus User Guide:  
#
# 				http://modis-fire.umd.edu/files/MODIS_Burned_Area_Collection51_User_Guide_3.1.0.pdf
#
#  Example Run:  
#           
#            	python modis_download.py h01v10 /Users/lindynelson/Desktop 201304 201306
#     
#  
#  Arguments 
#    
#  Arg 1:  		h01v10 - tile to download
#  Arg 2: 		download location
#  Arg 3: 		begin month and year (inclusive)  YYYYMM
#  Arg 4:       end month and year (inclusive)  YYYYMM
#
#
#===============================================================================





import ftplib
import datetime
import sys
import os





#===============================================================================
#function get_all_files_for_tile
#
#input:  	the tile that was entered as arg 1
#output: 	the list of files that are in the data directory 
#===============================================================================

def get_all_files_for_tile(tile):
    
    username = 'fire'
    password = 'burnt' 
    modis_ftp_url = 'fuoco.geog.umd.edu'
    ftp_data_directory = '/db/MCD64A1/%s/' %tile
    
    ftp = ftplib.FTP(modis_ftp_url, username, password)
    global ftp
    ftp.cwd(ftp_data_directory)
    file_list = ftp.nlst(ftp_data_directory)
    return file_list






#===============================================================================
#function download
#
#input:  	filename to download
#			directory to download
#desc:   	download given filename to given local data_dir
#===============================================================================

def download(filename, data_dir):    

    '''
    params: filename to download
            directory for download
    desc:   download given filename to given local data_dir
    '''
    
    assert os.path.isdir(data_dir), 'FTP download failed. Not a directory: %s' %data_dir
    
    retr_cmd = 'RETR %s' %filename

    local_file = os.path.join(data_dir, filename)

    fp = open(local_file, 'wb')

    ftp.retrbinary(retr_cmd, fp.write)

    fp.close()
 







#===============================================================================
#function download_files
#
#input:  	filename to download
#			directory to download
#desc: 		downloads all files from start_month to end_month for given tile
#===============================================================================


def download_files(tile, data_dir, start_month, end_month):
    
    """
    download all files from start_month to end_month(inclusive) for given tile
    """
    
    def filename_is_between_months(filename, start_month_arg, end_month_arg):

        
        filename_parts = filename.split('.')
        tile_id = filename_parts[2]
        julian_day = filename_parts[1][1:]
        year = int(julian_day[:4])
        day = int(julian_day[4:])

        date = datetime.datetime(year, 1, 1) + datetime.timedelta(day -1) 

        start_dt_obj = datetime.datetime.strptime(start_month, '%Y%m')
        end_dt_obj = datetime.datetime.strptime(end_month, '%Y%m')
        bool_ret_val = (date >= start_dt_obj and date <= end_dt_obj)

        return bool_ret_val

    file_list = get_all_files_for_tile(tile)
    files_to_download = [filename for filename in file_list if filename_is_between_months(filename, start_month, end_month)]

    for filename in files_to_download:
        print('downloading file: %s' %filename )
        download(filename, data_dir)





    
#===============================================================================
#function main
#===============================================================================      

def main():
    
    assert len(sys.argv) is 5, 'Usage: download_modis.py tile data_dir start_month end_month'
    tile, data_dir, start_month, end_month = sys.argv[1:]
    assert len(start_month) is 6, 'Invalid month format %s: start_month must be in format of YYYYMM, e.g. 201308' %start_month
    assert os.path.isdir(data_dir), 'Please specify an existing directory.  Not a directory: %s' %data_dir
    assert len(end_month) is 6, 'Invalid month format %s: end_month must be in format of YYYYMM, e.g. 201308' %end_month    
    assert int(start_month), 'Invalid month format %s: start_month must be in format of YYYYMM, e.g. 201308' %start_month
    assert int(end_month), 'Invalid month format %s: end_month must be in format of YYYYMM, e.g. 201308' %end_month    

    download_files(tile, data_dir, start_month, end_month)


if __name__ == "__main__":

   main()