Add example

.gitignore

@@ -3,3 +3,4 @@
 *.egg-info/
 build/
 .cache/
+example/

example.py

@@ -0,0 +1,43 @@
+import shutil
+import urllib.request
+import zipfile
+from pathlib import Path
+
+import pycolmap
+from pycolmap import logging
+
+
+def run():
+    output_path = Path("example/")
+    image_path = output_path / "Fountain/images"
+    database_path = output_path / "database.db"
+    sfm_path = output_path / "sfm"
+
+    output_path.mkdir(exist_ok=True)
+    logging.set_log_destination(logging.INFO, output_path / "INFO.log.")  # + time
+
+    data_url = "https://cvg-data.inf.ethz.ch/local-feature-evaluation-schoenberger2017/Strecha-Fountain.zip"
+    if not image_path.exists():
+        logging.info("Downloading the data.")
+        zip_path = output_path / "data.zip"
+        urllib.request.urlretrieve(data_url, zip_path)
+        with zipfile.ZipFile(zip_path, "r") as fid:
+            fid.extractall(output_path)
+        logging.info(f"Data extracted to {output_path}.")
+
+    if database_path.exists():
+        database_path.unlink()
+    pycolmap.extract_features(database_path, image_path)
+
+    pycolmap.match_exhaustive(database_path)
+
+    if sfm_path.exists():
+        shutil.rmtree(sfm_path)
+    sfm_path.mkdir(exist_ok=True)
+    recs = pycolmap.incremental_mapping(database_path, image_path, sfm_path)
+    for idx, rec in recs.items():
+        logging.info(f"#{idx} {rec.summary()}")
+
+
+if __name__ == "__main__":
+    run()