【Python】画像から GeoJSON / KML ファイルを作る

import glob
import os
import numpy as np
from PIL import Image
import geojson
from xml.etree.ElementTree import Element, SubElement, tostring, ElementTree

# 画像パスの取得
image_paths = glob.glob('./*.png')  

for image_num in range(len(image_paths)):

    # グレースケール画像の読み込み
    image_path = image_paths[image_num]
    print(f'画像の読み込み: {image_path}')
    image = Image.open(image_path).convert('L') 
    image_array = np.array(image)

    # 黒またはグレーのピクセルの座標を取得（閾値を128とする）
    threshold = 128
    dark_pixels = np.argwhere(image_array <= threshold)

    # Y座標を逆にして左下を基準にする
    height, width = image_array.shape
    dark_pixels[:, 0] = height - dark_pixels[:, 0] - 1

    # 座標を経緯度に変換
    dark_pixels[:, 0] = dark_pixels[:, 0] - height / 2
    dark_pixels[:, 1] = dark_pixels[:, 1] - width / 2
    if width >= height * 2:
        normalized_dark_pixels = dark_pixels / width * 200
    else:
        normalized_dark_pixels = dark_pixels / height * 100

    # GeoJSONのFeatureリストを作成
    features = []
    for pixel in normalized_dark_pixels:
        y, x = pixel
        point = geojson.Point((x, y))
        feature = geojson.Feature(geometry=point)
        features.append(feature)

    # GeoJSONファイルの作成
    feature_collection = geojson.FeatureCollection(features)
    output_path = os.path.splitext(os.path.basename(image_path))[0] + '.json'
    with open(output_path, 'w') as f:
        geojson.dump(feature_collection, f)
    print(f'GeoJSONファイルが作成されました: {output_path}')

    # KMLファイルの作成
    kml_output_path = os.path.splitext(os.path.basename(image_path))[0] + '.kml'
    kml = Element('kml', xmlns="http://www.opengis.net/kml/2.2")
    document = SubElement(kml, 'Document')
    for pixel in normalized_dark_pixels:
        y, x = pixel
        placemark = SubElement(document, 'Placemark')
        point = SubElement(placemark, 'Point')
        coordinates = SubElement(point, 'coordinates')
        coordinates.text = f'{x},{y},0'
    tree = ElementTree(kml)
    tree.write(kml_output_path, encoding='utf-8', xml_declaration=True)
    print(f'KMLファイルが作成されました: {kml_output_path}')