make_patch_img.py

#!/usr/bin/env python3
# make patch images.

import subprocess
import argparse
import os
import re


def main():
    parser = argparse.ArgumentParser(usage="make patch images from satellite imgase.\n" +
            "%(prog)s [img_dir] [out_dir] [size] [center_lat] [center_lon]\n" + 
            "ex) %(prog)s /path/to/img_dir /path/to/out_dir 10 36.1 140.1")
    #parser = argparse.ArgumentParser(description="make patch images from satellite imgase.")
    parser.add_argument('img_dir', action='store', type=str, 
                        help='directory where the input images are stored.')
    parser.add_argument('out_dir', action='store', type=str,
                       help='directory whre the output images are stored.')
    parser.add_argument('size', action='store', type=int,
                       help='radius size of the image to cut out. ')
    parser.add_argument('center_lat', action='store', type=float,
                       help='center latitude of the image to cut out. ')
    parser.add_argument('center_lon', action='store', type=float,
                       help='center longitude of the image to cut out. ')
    
    args = parser.parse_args()
    
    # set parameter
    img_dir = args.img_dir
    out_dir = args.out_dir
    size = args.size
    center_lat = args.center_lat
    center_lon = args.center_lon
    
    # get img list from img_dir
    img_list = get_img_list(img_dir)
    
    print("start making patch images ...")
    for img_file in img_list:
        make_patch_image(img_dir, img_file, out_dir, center_lat, center_lon, size)
        
    print("complete process.")


def get_img_list(imgdir):
    """ get tif list from imgdir.(helper functoin.)"""
    imgdir_list = os.listdir(imgdir)
    img_list = [f for f in imgdir_list if re.match(r'.*tif$', f)]
    return img_list


def make_patch_image(img_dir, img_file, out_dir,center_lat, center_lon, size):
    """ make patch image using gdal_translate command.
    input:
        img_dir : img directory.
        img_file: img file which you want to cut.
        out_dir : save directory.
        center_lat: center latitude.
        centa_lon: center longitude.
        size: (unit:meter)
    
    output:

    """
    # assume 1deg=110km; so 1m=9.09e-6
    one_meter=9.090909090909091e-06 
    distance = one_meter * size # unit: degree
    
    # set coordinate.
    upper_left_x = str(center_lon - distance)
    upper_left_y = str(center_lat + distance)
    lower_right_x= str(center_lon + distance)
    lower_right_y= str(center_lat - distance)
    
    command = ["gdal_translate", "-projwin",
               upper_left_x, upper_left_y,
              lower_right_x, lower_right_y,
               img_dir + "/" + img_file,
               out_dir + "/" + img_file]
    # run gdal_command
    subprocess.run(command)


if __name__ == '__main__':
    main()