Match county names to predefined list

Question

I read large lists of county names that people wrote down manually and now need to be matched to a predefined list of counties.

I understand that those matches cannot be perfect, but the operator should be shown a list of "wrong" county names together with their best matches, and ideally needs just to click "ok" to proceed and use them.

Until now, I just use levenshtein distance, which is great for catching typos, but not great for abbreviations. Real world examples that would be obvious to a human, but which levenshtein does not match correctly:

• Input: Siegen
• Should be: Siegen-Wittgenstein
• Levenshtein: Hagen

or

• Input: Rhein.-Berg. Kreis
• Should be: Rheinisch-Bergischer Kreis
• Levenshtein: Rhein-Sieg-Kreis

How can I catch those abbreviations as well?

I use PHP, but this more a question about the right algorithm than about PHP.

Answer 1

As you're dealing with geographic data, perhaps a geocoding approach could work? An example API would be Nominatim, but there are many other (paid) options.

If I use your two examples in the debugging interface of Nominatim I get the following:

Example 1:

• Input: Siegen
• Expected output: Siegen-Wittgenstein
• Nominatim outputs (link):
  • Siegen, Kreis Siegen-Wittgenstein, North Rhine-Westphalia, Germany
  • Siegen, Haguenau-Wissembourg, Bas-Rhin, Grand Est, Metropolitan France, 67160, France
  • Siegen, Kreis Siegen-Wittgenstein, North Rhine-Westphalia, 57072, Germany

Example 2:

• Input: Rhein.-Berg. Kreis
• Expected output: Rheinisch-Bergischer Kreis
• Nominatim outputs (link):
  • Geschäftsstelle DRK Kreisverband Rhein.-Berg. Kreis, 261, Hauptstraße, Heidkamp, Bergisch Gladbach, Rheinisch-Bergischer Kreis, North Rhine-Westphalia, 51465, Germany
  • Auf dem Kreis, Bad Berleburg, Kreis Siegen-Wittgenstein, North Rhine-Westphalia, Germany
  • Region Rhein-Neckar (HE), Kreis Bergstraße, Hesse, Germany

The quality is mixed, it definitely requires additional filtering. Without any additional filtering you get various resulttypes (administrative regions, a mountain peak, a charity) and also various countries (Germany and France).

However, you can apply filters on the detailed output to return only county names in a specific country to get the output you want.