download_panoramas.py

# Download panorama images (0, 90, 180, 270 stitching) with duplicate detection and 404 error handling
# Input: CSV file (e.g., selected_data.csv) containing panoid field
# Output: Panorama images saved to save_dir
import os
from PIL import Image
import requests
import io
import csv
from tqdm import tqdm
import dotenv
import pandas as pd
import re
from time import sleep
import random

dotenv.load_dotenv("../.env")
API_KEY = os.getenv('GOOGLE_MAP_API_KEY')
base_url = 'https://maps.googleapis.com/maps/api/streetview'
save_dir = '/home/xiuying.chen/jingpu/data/panoramas'
csv_path = '/home/xiuying.chen/jingpu/data/exist_pano.csv'

headings = {
    'north': '0',
    'east': '90',
    'south': '180',
    'west': '270',
}

def get_street_view_image(pano_id):
    params = {
        'size': '640x640',
        'pano': pano_id,
        'key': API_KEY,
        'pitch': '0',
        'return_error_code': 'true'
    }

    images = []
    error_panoids = []

    # Download images facing east, south, west, and north
    for direction, heading in headings.items():
        params['heading'] = heading
        sleep(random.randint(1, 5))
        response = requests.get(base_url, params=params)
        print(f'{direction} request status:', response.status_code)
        if response.status_code == 200:
            images.append(Image.open(io.BytesIO(response.content)))
            image_filename = f'{pano_id}_{direction}.jpg'
            save_path = os.path.join(save_dir, image_filename)
            with open(save_path, 'wb') as f:
                f.write(response.content)
            print(f'Saved {image_filename}')
        elif response.status_code == 404:
            if pano_id not in error_panoids:
                error_panoids.append(pano_id)
            print(f'Failed to get the {direction} image, panoid: {pano_id} does not exist')
            
    # If there are panoids causing a 404, write them to 404panoid.csv
    if error_panoids:
        error_df = pd.DataFrame(error_panoids, columns=['panoid'])
        error_df.to_csv('404panoid.csv', mode='a', header=not os.path.exists('404panoid.csv'), index=False)

    # Stitch images together to form a panorama
    try:
        # Calculate the dimensions of the final panorama image
        width = sum(img.width for img in images)
        height = images[0].height
        
        # Create a new image and stitch the downloaded images together
        panorama = Image.new('RGB', (width, height))
        x_offset = 0
        for img in images:
            panorama.paste(img, (x_offset, 0))
            x_offset += img.width
        
        # Save the panorama image
        output_path = os.path.join(save_dir, f'{pano_id}_panoramic.jpg')
        panorama.save(output_path, quality=95)

        # Update exist_pano.csv with the new panoid information
        new_row = {'panoid': pano_id, 'address': save_dir}
        existing_data = pd.read_csv(csv_path) if os.path.exists(csv_path) else pd.DataFrame(columns=['panoid', 'address'])
        existing_data = existing_data._append(new_row, ignore_index=True)
        existing_data.to_csv(csv_path, index=False)
        return output_path
        
    except Exception as e:
        print(f"Error downloading panorama: {str(e)}")
        return None

def check_panoramas_exist(panoid):
    """Check if the given panoid has already been crawled"""
    csv_path = '/home/xiuying.chen/jingpu/data/exist_pano.csv'
    
    # Read existing panoid data
    if not os.path.exists(csv_path):
        return False  # If the file does not exist, return False

    existing_data = pd.read_csv(csv_path)
    
    # Check if the panoid exists in the 'panoid' column
    return panoid in existing_data['panoid'].values

def read_pano_ids(file_path):
    pano_ids = []
    with open(file_path, 'r', encoding='utf-8') as f:
        reader = csv.DictReader(f)  # Use DictReader to read the CSV file
        for row in reader:
            pano_id = row['panoID']  
            pano_ids.append((pano_id))  # Add the panoid to the list 
    return pano_ids

def load_exist_pano(scaned_dir):
    """Read .jpg files in the specified directory and update exist_pano.csv"""
    # Read existing panoid data
    csv_path = '/home/xiuying.chen/jingpu/data/exist_pano.csv'
    if os.path.exists(csv_path):
        existing_data = pd.read_csv(csv_path)
    else:
        print("exist_pano.csv not found, quit")
        return

    # Iterate over all .jpg files in the specified directory
    for filename in os.listdir(scaned_dir):
        if filename.endswith('.jpg'):
            # Use regex to extract the panoid by removing the directional suffix
            match = re.match(r'^(.*?)(?:_east|_north|_south|_west|_panoramic)\.jpg$', filename)
            if match:
                panoid = match.group(1)  # Extract the panoid part

                # Check whether the panoid already exists
                if panoid not in existing_data['panoid'].values:
                    # Create a new row and save the file address
                    new_row = {'panoid': panoid, 'address': scaned_dir}
                    existing_data = existing_data._append(new_row, ignore_index=True)

    # Write the updated data back to the CSV file
    existing_data.to_csv(csv_path, index=False)

if __name__ == '__main__':
    pano_ids = read_pano_ids("GT.csv")
    for pano_id in tqdm(pano_ids, desc="Downloading street view images"):
        # Check whether the image has already been downloaded
        if check_panoramas_exist(pano_id):
            # print(f'{pano_id} already exists')
            continue
        else:
            # print(f'{pano_id} does not exist')
            sleep(5)
            get_street_view_image(pano_id)
            print(f'{pano_id} downloaded')