Cities

Filter

This filter identifies common US cities as determined by the US census in text.

Required Parameters

This filter has no required parameters.

Optional Parameters

Parameter	Description	Default Value
cityFilterStrategies	A list of filter strategies.	None
fuzzy	When set to true, matching is fuzzy, using sensitivity to control the fuzziness. When false, terms are matched exactly, ignoring case.	false
sensitivity	How close a word must be to a term to be reported when fuzzy is true, measured in edits (a character inserted, removed, or changed). high reports only exact matches, medium allows one edit, and low allows up to two. off reports only exact matches. auto allows no edits for a word under five characters, one edit for a word under nine, and two for a longer word, counts two swapped neighboring letters as one edit (so Smiht is one edit from Smith), and reports a fuzzy match only when it begins with a capital letter, which helps keep common short words such as and and the from matching names and places. Words shorter than three characters, not counting punctuation around them, are not compared. Any other value refuses the policy when it is saved, even when fuzzy is false.	auto
terms	A list of terms to detect in place of the list bundled with Philter. When given, only these terms are detected and the bundled list is not used; an empty list uses the bundled list. They are matched the way fuzzy says: exactly, ignoring case, or fuzzily.	None (the bundled list)
capitalized	When set to true, a match is reported only when its first letter is uppercase, so a term that is also an ordinary word is not reported when written in lowercase. Applies only when fuzzy is set to true; with exact matching it has no effect, and a match is reported whatever its case.	false

Cities That Are Common Words

About 1,300 names in the bundled list are also common English words, such as Call, Driver, Hope, Center, Phoenix, and Mobile. One of these is reported as a city only when it begins with a capital letter and either follows in, from, to, near, outside, toward, towards, or via (Born in Phoenix.), or is followed by a comma and a state name or two-letter state abbreviation (Mobile, Alabama, Reading, PA). So Call the clinic with questions. and She lives on Oak Street in Austin. report only Austin. Other names in the list are reported wherever they appear. The rule does not apply to terms.

Such a city written without that context, as in Phoenix is hot this summer. or lives in phoenix, is not reported. To find it wherever it appears, list the cities you need in terms. A capitalized common word after a location word, as in a title such as Welcome to Paradise, is reported; list such words in ignored.

Filter Strategies

The filter may have zero or more filter strategies. When no filter strategy is given the default strategy of REDACT is used. When multiple filter strategies are given, they are evaluated in the order listed and only the first one whose condition is satisfied, or that has no condition, is applied. See Filter Strategies for details.

Strategy	Description
REDACT	Replace the sensitive text with a placeholder.
RANDOM_REPLACE	Replace the sensitive text with a similar, random value.
STATIC_REPLACE	Replace the sensitive text with a given value.
CRYPTO_REPLACE	Replace the sensitive text with its encrypted value.
HASH_SHA256_REPLACE	Replace the sensitive text with its SHA256 hash value.

Conditions

Each filter strategy may have one condition. See Conditions for details.

Conditional	Description	Operators
TOKEN	Compares the value of the sensitive text.	==, !=, startswith
CONTEXT	Compares the filtering context.	== , !=
CONFIDENCE	Compares the confidence in the sensitive text against a threshold value.	< , <=, > , >=, ==, !=

Example Policy

{
   "identifiers": {
      "city": {
         "fuzzy": true,
         "sensitivity": "medium",
         "cityFilterStrategies": [
            {
               "strategy": "REDACT",
               "redactionFormat": "{{{REDACTED-%t}}}"
            }
         ]
      }
   }
}

Using your own terms

To detect only your own list of terms, give them in terms. With fuzzy set to true, close misspellings of a term can also be detected, as sensitivity allows; with capitalized also set to true, a term written in lowercase is not reported:

{
   "identifiers": {
      "city": {
         "terms": ["Springfield", "Shelbyville"],
         "fuzzy": true,
         "capitalized": true,
         "cityFilterStrategies": [
            {
               "strategy": "REDACT",
               "redactionFormat": "{{{REDACTED-%t}}}"
            }
         ]
      }
   }
}