Finding an address

Entering an address

For optimal performance and match rates, input an address free of misspellings and with all known address components. If you are using GeoStan for mailable address standardization, to obtain the highest match rate, verify that your input follows USPS standards.

GeoStan accepts many input fields that make up an address. Ensure that your input address contains a street address line and a last line, or a singleline with both address and last line elements. These inputs help ensure that GeoStan can accurately identify a location area in which to search for a match candidate based on the city, state, and ZIP Code. GeoStan can also perform address matching with only a city in the input lastline; however, certain restrictions do apply - for more information, see City-only lastline matching.

GeoStan also accepts a street address line with individual city, state, and ZIP Code fields instead of a last line. Use this type of input configuration if you are confident that you have a complete address list; free of misspellings and incomplete addresses.

If you are using GeoStan for address standardization or geocoding, GeoStan requires addresses to have at least a street name, and either a city or a ZIP Code to obtain a match and a geocode. The addition of a state will help resolve multiple matches if only entering a city, but it is not required.

Understanding the typical address

The typical address consists of the following elements:

GeoStan also recognizes the elements on individual input lines when matching in multiline mode.

Understanding how GeoStan processes addresses

GeoStan processes addresses in the following order:

1. Parses the address elements.

   When you load data in GeoStan, GeoStan parses the data into single elements. Parsing occurs on data in the order in which you load the data. Even if a valid address is missing an element, GeoStan can find a match. In addition, some elements, such as predirectionals, may not be critical elements of some addresses. By comparing an address as input against all known addresses in a search area, GeoStan can usually determine if any of these elements are missing or incorrect.

2. Determines the search area.

   GeoStan uses the last line elements of an address to determine a search area. You can specify if you want the search area to be based on a finance area or on an area defined by the city, state, and ZIP Code. If the city and state are not in the ZIP Code, GeoStan performs separate searches for the ZIP Code and city.

   Note: A finance area is a collection of ZIP Codes within a contiguous geographic region.

3. Finds possible matches within the search area.

   Once GeoStan has determined the search area, it tries to match the elements from the street address line to the records in the standardized data files and completes the following:

   • Checks input address ranges for missing or misplaced hyphens, and alpha-numeric ranges for proper sequence.

   • Searches for any misspellings and standard abbreviations. For example, GeoStan can recognize Mane for Main and KC for Kansas City.

   • Searches for any street name alias matches to the USPS and Spatial data (TIGER, TomTom, User Dictionaries, HERE (formerly NAVTEQ) and Points). For example, GeoStan recognizes that in Boulder, "CO Highway 36" is also known as "28th Street".

   Note: The USPS does not consider matches to data that they did not create and these are not considered valid addresses for postal delivery. Therefore, GeoStan does not match to any spatial alias data, User Dictionaries, or auxiliary files, when processing in CASS mode.

   • Searches for addresses that contain a house number and unit number as the same element. For example, GeoStan recognizes the input 4750-200 Walnut Street and performs recombination to output 4750 WALNUT ST STE 200

   • Searches for any USPS recognized firm names for additional match verification.

   • Searches for street intersection matches. GeoStan recognizes and, &, &&, at, AT, and @ in the input address for an intersection match.

   Note: The USPS does not consider intersections valid addresses for postal delivery. Therefore, GeoStan does not match intersections when processing in CASS mode.

4. Scores each possible match against the parsed input.

   Note: If you need to develop your own scoring system, use the Find functions. For more information, see Appendix B: Extracting Data from GSD Files.

   GeoStan compares each element in the input address to the corresponding element in the match candidates, and assigns a confidence level. GeoStan weighs the confidence level for all of the elements within a match candidate, and assigns a final score.

   Note: GeoStan uses a penalty scoring system. If an element does not exactly match an element in the match candidate, GeoStan adds a penalty to the score of the match candidate. Therefore, scores with lower numbers are better matches.

5. Determines the match.

GeoStan prioritizes each match candidate based on the assigned confidence score and returns as a match the candidate that has the lowest score.

The match mode you choose determines the range that GeoStan allows for a match. GeoStan only returns a match if the score of the target address falls within the range designated by the selected match mode.

In some cases, more than one match candidate may have the lowest score. In this instance, GeoStan cannot always determine on its own which record is correct, and returns a status indicating a match candidate. You can retrieve the list of possible matches, present them to the user, and allow the user to select one of the choices. Alternatively, you can resolve the matches internally in your application.

Along with a standardized address, GeoStan also returns the following:

Geocode   Longitude and latitude for the address

Match code   Information about the match of the input address to the reference data

Location code   Precision level of the geocode

Result code   GeoStan returns a result code for every record it attempts to match.

Street Parity   The side of the street on which the match resides.

Range Parity   The parity of the house number in the range: even, odd, or both.

Search area designation

To assist in finding a match when the input address contains limited or inaccurate city or ZIP Code information, GS_FIND_SEARCH_AREA may be set using one of the following options:

• 0 - GS_FIND_SEARCH_AREA_CITY - (default) Searches the specified city.

• 1 - GS_FIND_SEARCH_AREA_FINANCE - Searches the entire Finance Area for possible streets.

• 2 - GS_FIND_SEARCH_AREA_EXPANDED - This value effectively has two options that can be set:

  • Allows the setting of the radius in miles (up to 99) around which your record lies. The default radius setting is 25 miles.

  • Allows for limiting the search to the state. The default setting is True.

When the value of GS_FIND_SEARCH AREA is set to GS_FIND_SEARCH_AREA_EXPANDED, you can set two other properties that tell GeoStan how far to expand the search. To set the radius, use the property, GS_FIND_EXPANDED_SEARCH_RADIUS and specify the number of feet to search around the area defined by the Last-line lookup information. To limit the search to the state, even if the radius would extend past state borders, set the property GS_FIND_EXPND_SRCH_LIM_TO_STATE to True.

These expanded search options allow for searching within a city, its finance areas (groups of ZIP Codes as defined by the USPS), or by specifying the radius searched in miles.

Hyphenated addresses

GeoStan handles hyphens in address ranges. Address ranges are checked for missing or misplaced hyphens. Alpha-numeric ranges are checked for proper sequence.

If a house number is incorrectly entered with a hyphen, the number is first concatenated. If no match is resolved, GeoStan tries the section of the house number following the hyphen as a unit number. See Matching address ranges for special processing of hyphens.

Parsing city names

GeoStan correctly parses out the separate elements of City, State, and ZIP Code from the data entered under GS_LASTLINE. When the city element is preparsed using GS_CITY, GeoStan parsing is bypassed. For example, "Mt Pilot" entered into GS_CITY would not be parsed to look for "Mount Pilot." Best results are obtained keeping all three elements under GS_LASTLINE.