Add --ignore-ssl-errors flag and SSL certificate documentation

[philipdenys]

Summary

This PR adds support for bypassing SSL certificate verification errors commonly encountered on macOS when Python certificates are not properly installed.

Problem

Users on macOS with Python installed from python.org frequently encounter SSL certificate verification errors when the script tries to geocode cities using the Nominatim API:

SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1002)'))

Changes Made

1. New Command-Line Flag

• Added --ignore-ssl-errors flag to bypass SSL certificate verification
• Includes warning message when flag is active
• Not recommended for production use - only for development/testing

2. SSL Patching Implementation

• Monkey-patches ssl._create_default_https_context when flag is enabled
• Lazy-loads geopy.geocoders.Nominatim to ensure patch takes effect before import
• Disables urllib3 SSL warnings to reduce noise
• Updated get_coordinates() function signature to accept the flag (though patching happens globally)

3. Documentation

• Created SSL_CERTIFICATE_ISSUE.md with:
  • Problem description and root cause explanation
  • Recommended solution: Run /Applications/Python X.XX/Install Certificates.command
  • Alternative solution: Use --ignore-ssl-errors flag (with security warnings)
  • Implementation details

Usage Example

Development/Testing (with flag):

python3 create_map_poster.py --ignore-ssl-errors -c Antwerp -C Belgium -t japanese_ink -d 15000

Recommended Approach (install certificates):

/Applications/Python\ 3.11/Install\ Certificates.command
python3 create_map_poster.py -c Antwerp -C Belgium -t japanese_ink -d 15000

Testing

• Tested on macOS with Python 3.11 experiencing SSL certificate errors
• Confirmed warning message appears when flag is used
• Verified lazy loading of geopy module

Security Note

The --ignore-ssl-errors flag is provided as a convenience for development and testing only. Users should be strongly encouraged to install proper SSL certificates using the recommended method.

Related Issues

Addresses SSL certificate verification failures on macOS when using Python installed from python.org (not system Python or Homebrew).

Fixes: Certificate verification errors with nominatim.openstreetmap.org geocoding requests