# Address Standardizer

This is a fork of the PAGC standardizer (original code for this portion was PAGC PostgreSQL Address Standardizer).

The address standardizer is a single line address parser that takes an input address and normalizes it based on a set of rules stored in a table and helper lex and gaz tables.

The code is built into a single PostgreSQL extension library called `address_standardizer` which can be installed with `CREATE EXTENSION address_standardizer;`. In addition to the address_standardizer extension, a sample data extension called `address_standardizer_data_us` extensions is built, which contains gaz, lex, and rules tables for US data. This extensions can be installed via: `CREATE EXTENSION address_standardizer_data_us;`

The code for this extension can be found in the PostGIS `extensions/address_standardizer` and is currently self-contained.

For installation instructions refer to: installing_pagc_address_standardizer.

## How the Parser Works

The parser works from right to left looking first at the macro elements for postcode, state/province, city, and then looks micro elements to determine if we are dealing with a house number street or intersection or landmark. It currently does not look for a country code or name, but that could be introduced in the future.

Country code

- Assumed to be US or CA based on: postcode as US or Canada state/province as US or Canada else US

Postcode/zipcode

- These are recognized using Perl compatible regular expressions. These regexs are currently in the parseaddress-api.c and are relatively simple to make changes to if needed.

State/province

- These are recognized using Perl compatible regular expressions. These regexs are currently in the parseaddress-api.c but could get moved into includes in the future for easier maintenance.

This section lists the PostgreSQL data types installed by Address Standardizer extension. Note we describe the casting behavior of these which is very important especially when designing your own functions.

## Address Standardizer Types

stdaddr

A composite type that consists of the elements of an address. This is the return type for `standardize_address` function.

#### Description

A composite type that consists of elements of an address. This is the return type for standardize_address function. Some descriptions for elements are borrowed from PAGC Postal Attributes.

The token numbers denote the output reference number in the rulestab.

&address_standardizer_required;

building

- is text (token number `0`): Refers to building number or name. Unparsed building identifiers and types. Generally blank for most addresses.

house_num

- is a text (token number `1`): This is the street number on a street. Example 75 in `75 State Street`.

predir

- is text (token number `2`): STREET NAME PRE-DIRECTIONAL such as North, South, East, West etc.

qual

- is text (token number `3`): STREET NAME PRE-MODIFIER Example OLD in `3715 OLD HIGHWAY 99`.

pretype

- is text (token number `4`): STREET PREFIX TYPE

name

- is text (token number `5`): STREET NAME

suftype

- is text (token number `6`): STREET POST TYPE e.g. St, Ave, Cir. A street type following the root street name. Example STREET in `75 State Street`.

sufdir

- is text (token number `7`): STREET POST-DIRECTIONAL A directional modifier that follows the street name.. Example WEST in `3715 TENTH AVENUE WEST`.

ruralroute

- is text (token number `8`): RURAL ROUTE . Example 7 in `RR 7`.

extra

- is text: Extra information like Floor number.

city

- is text (token number `10`): Example Boston.

state

- is text (token number `11`): Example `MASSACHUSETTS`

country

- is text (token number `12`): Example `USA`

postcode

- is text POSTAL CODE (ZIP CODE) (token number `13`): Example `02109`

box

- is text POSTAL BOX NUMBER (token number `14 and 15`): Example `02109`

unit

- is text Apartment number or Suite Number (token number `17`): Example 3B in `APT 3B`.

This section lists the PostgreSQL table formats used by the address_standardizer for normalizing addresses. Note that these tables do not need to be named the same as what is referenced here. You can have different lex, gaz, rules tables for each country for example or for your custom geocoder. The names of these tables get passed into the address standardizer functions.

The packaged extension `address_standardizer_data_us` contains data for standardizing US addresses.

## Address Standardizer Tables

rules table

The rules table contains a set of rules that maps address input sequence tokens to standardized output sequence. A rule is defined as a set of input tokens followed by -1 (terminator) followed by set of output tokens followed by -1 followed by number denoting kind of rule followed by ranking of rule.

#### Description

A rules table must have at least the following columns, though you are allowed to add more for your own uses.

id

- Primary key of table

rule

- text field denoting the rule. Details at PAGC Address Standardizer Rule records.

  A rule consists of a set of non-negative integers representing input tokens, terminated by a -1, followed by an equal number of non-negative integers representing postal attributes, terminated by a -1, followed by an integer representing a rule type, followed by an integer representing the rank of the rule. The rules are ranked from 0 (lowest) to 17 (highest).

  So for example the rule `2 0 2 22 3 -1 5 5 6 7 3 -1 2 6` maps to sequence of output tokens TYPE NUMBER TYPE DIRECT QUALIF to the output sequence STREET STREET SUFTYP SUFDIR QUALIF. The rule is an ARC_C rule of rank 6.

  Numbers for corresponding output tokens are listed in stdaddr.

#### Input Tokens

Each rule starts with a set of input tokens followed by a terminator `-1`. Valid input tokens excerpted from PAGC Input Tokens are as follows:

Form-Based Input Tokens

AMPERS

- (13). The ampersand (&) is frequently used to abbreviate the word "and".

DASH

- (9). A punctuation character.

DOUBLE

- (21). A sequence of two letters. Often used as identifiers.

FRACT

- (25). Fractions are sometimes used in civic numbers or unit numbers.

MIXED

- (23). An alphanumeric string that contains both letters and digits. Used for identifiers.

NUMBER

- (0). A string of digits.

ORD

- (15). Representations such as First or 1st. Often used in street names.

ORD

- (18). A single letter.

WORD

- (1). A word is a string of letters of arbitrary length. A single letter can be both a SINGLE and a WORD.

Function-based Input Tokens

BOXH

- (14). Words used to denote post office boxes. For example Box or PO Box.

BUILDH

- (19). Words used to denote buildings or building complexes, usually as a prefix. For example: Tower in Tower 7A.

BUILDT

- (24). Words and abbreviations used to denote buildings or building complexes, usually as a suffix. For example: Shopping Centre.

DIRECT

- (22). Words used to denote directions, for example North.

MILE

- (20). Words used to denote milepost addresses.

ROAD

- (6). Words and abbreviations used to denote highways and roads. For example: the Interstate in Interstate 5

RR

- (8). Words and abbreviations used to denote rural routes. RR.

TYPE

- (2). Words and abbreviation used to denote street typess. For example: ST or AVE.

UNITH

- (16). Words and abbreviation used to denote internal subaddresses. For example, APT or UNIT.

Postal Type Input Tokens

QUINT

- (28). A 5 digit number. Identifies a Zip Code

QUAD

- (29). A 4 digit number. Identifies ZIP4.

PCH

- (27). A 3 character sequence of letter number letter. Identifies an FSA, the first 3 characters of a Canadian postal code.

PCT

- (26). A 3 character sequence of number letter number. Identifies an LDU, the last 3 characters of a Canadian postal code.

Stopwords

STOPWORDS combine with WORDS. In rules a string of multiple WORDs and STOPWORDs will be represented by a single WORD token.

STOPWORD

- (7). A word with low lexical significance, that can be omitted in parsing. For example: THE.

#### Output Tokens

After the first -1 (terminator), follows the output tokens and their order, followed by a terminator `-1`. Numbers for corresponding output tokens are listed in stdaddr. What are allowed is dependent on kind of rule. Output tokens valid for each rule type are listed in rule_types_rank.

#### Rule Types and Rank

The final part of the rule is the rule type which is denoted by one of the following, followed by a rule rank. The rules are ranked from 0 (lowest) to 17 (highest).

MACRO_C

(token number = "0"). The class of rules for parsing MACRO clauses such as PLACE STATE ZIP

MACRO_C output tokens (excerpted from http://www.pagcgeo.org/docs/html/pagc-12.html#--r-typ--.

CITY

- (token number "10"). Example "Albany"

STATE

- (token number "11"). Example "NY"

NATION

- (token number "12"). This attribute is not used in most reference files. Example "USA"

POSTAL

- (token number "13"). (SADS elements "ZIP CODE" , "PLUS 4" ). This attribute is used for both the US Zip and the Canadian Postal Codes.

MICRO_C

(token number = "1"). The class of rules for parsing full MICRO clauses (such as House, street, sufdir, predir, pretyp, suftype, qualif) (ie ARC_C plus CIVIC_C). These rules are not used in the build phase.

MICRO_C output tokens (excerpted from http://www.pagcgeo.org/docs/html/pagc-12.html#--r-typ--.

HOUSE

- is a text (token number `1`): This is the street number on a street. Example 75 in `75 State Street`.

predir

- is text (token number `2`): STREET NAME PRE-DIRECTIONAL such as North, South, East, West etc.

qual

- is text (token number `3`): STREET NAME PRE-MODIFIER Example OLD in `3715 OLD HIGHWAY 99`.

pretype

- is text (token number `4`): STREET PREFIX TYPE

street

- is text (token number `5`): STREET NAME

suftype

- is text (token number `6`): STREET POST TYPE e.g. St, Ave, Cir. A street type following the root street name. Example STREET in `75 State Street`.

sufdir

- is text (token number `7`): STREET POST-DIRECTIONAL A directional modifier that follows the street name.. Example WEST in `3715 TENTH AVENUE WEST`.

ARC_C

(token number = "2"). The class of rules for parsing MICRO clauses, excluding the HOUSE attribute. As such uses same set of output tokens as MICRO_C minus the HOUSE token.

CIVIC_C

(token number = "3"). The class of rules for parsing the HOUSE attribute.

EXTRA_C

(token number = "4"). The class of rules for parsing EXTRA attributes - attributes excluded from geocoding. These rules are not used in the build phase.

EXTRA_C output tokens (excerpted from http://www.pagcgeo.org/docs/html/pagc-12.html#--r-typ--.

BLDNG

- (token number `0`): Unparsed building identifiers and types.

BOXH

- (token number `14`): The BOX in `BOX 3B`

BOXT

- (token number `15`): The 3B in `BOX 3B`

RR

- (token number `8`): The RR in `RR 7`

UNITH

- (token number `16`): The APT in `APT 3B`

UNITT

- (token number `17`): The 3B in `APT 3B`

UNKNWN

- (token number `9`): An otherwise unclassified output.

lex table

A lex table is used to classify alphanumeric input and associate that input with (a) input tokens ( See rule_input_tokens) and (b) standardized representations.

#### Description

A lex (short for lexicon) table is used to classify alphanumeric input and associate that input with rule_input_tokens and (b) standardized representations. Things you will find in these tables are `ONE` mapped to stdword: `1`.

A lex has at least the following columns in the table. You may add

id

- Primary key of table

seq

- integer: definition number?

word

- text: the input word

stdword

- text: the standardized replacement word

token

- integer: the kind of word it is. Only if it is used in this context will it be replaced. Refer to PAGC Tokens.

gaz table

A gaz table is used to standardize place names and associate that input with (a) input tokens ( See rule_input_tokens) and (b) standardized representations.

#### Description

A gaz (short for gazeteer) table is used to standardize place names and associate that input with rule_input_tokens and (b) standardized representations. For example if you are in US, you may load these with State Names and associated abbreviations.

A gaz table has at least the following columns in the table. You may add more columns if you wish for your own purposes.

id

- Primary key of table

seq

- integer: definition number? - identifer used for that instance of the word

word

- text: the input word

stdword

- text: the standardized replacement word

token

- integer: the kind of word it is. Only if it is used in this context will it be replaced. Refer to PAGC Tokens.

## Address Standardizer Functions

parse_address

Takes a 1 line address and breaks into parts

    					record parse_address
    					text  address

#### Description

Returns takes an address as input, and returns a record output consisting of fields num, street, street2, address1, city, state, zip, zipplus, country.

Availability: 2.2.0

&address_standardizer_required;

#### Examples

Single Addresss

    SELECT num, street, city, zip, zipplus
    	FROM parse_address('1 Devonshire Place, Boston, MA 02109-1234') AS a;

     num |      street      |  city  |  zip  | zipplus
    -----+------------------+--------+-------+---------
     1   | Devonshire Place | Boston | 02109 | 1234

Table of addresses

    -- basic table
    CREATE TABLE places(addid serial PRIMARY KEY, address text);

    INSERT INTO places(address)
    VALUES ('529 Main Street, Boston MA, 02129'),
     ('77 Massachusetts Avenue, Cambridge, MA 02139'),
     ('25 Wizard of Oz, Walaford, KS 99912323'),
     ('26 Capen Street, Medford, MA'),
     ('124 Mount Auburn St, Cambridge, Massachusetts 02138'),
     ('950 Main Street, Worcester, MA 01610');

     -- parse the addresses
     -- if you want all fields you can use (a).*
    SELECT addid, (a).num, (a).street, (a).city, (a).state, (a).zip, (a).zipplus
    FROM (SELECT addid, parse_address(address) As a
     FROM places) AS p;

     addid | num |        street        |   city    | state |  zip  | zipplus
    -------+-----+----------------------+-----------+-------+-------+---------
         1 | 529 | Main Street          | Boston    | MA    | 02129 |
         2 | 77  | Massachusetts Avenue | Cambridge | MA    | 02139 |
         3 | 25  | Wizard of Oz         | Walaford  | KS    | 99912 | 323
         4 | 26  | Capen Street         | Medford   | MA    |       |
         5 | 124 | Mount Auburn St      | Cambridge | MA    | 02138 |
         6 | 950 | Main Street          | Worcester | MA    | 01610 |
    (6 rows)

#### See Also

standardize_address

Returns an stdaddr form of an input address utilizing lex, gaz, and rule tables.

    					stdaddr standardize_address
    					text  lextab
    					text  gaztab
    					text  rultab
    					text  address

    					stdaddr standardize_address
    					text  lextab
    					text  gaztab
    					text  rultab
    					text  micro
    					text  macro

#### Description

Returns an stdaddr form of an input address utilizing lextab table name, gaztab, and rulestab table names and an address.

Variant 1: Takes an address as a single line.

Variant 2: Takes an address as 2 parts. A `micro` consisting of standard first line of postal address e.g. `house_num street`, and a macro consisting of standard postal second line of an address e.g `city, state postal_code country`.

Availability: 2.2.0

&address_standardizer_required;

#### Examples

Using address_standardizer_data_us extension

    CREATE EXTENSION address_standardizer_data_us; -- only needs to be done once

Variant 1: Single line address. This doesn't work well with non-US addresses

    SELECT house_num, name, suftype, city, country, state, unit  FROM standardize_address('us_lex',
    			   'us_gaz', 'us_rules', 'One Devonshire Place, PH 301, Boston, MA 02109');

    house_num |    name    | suftype |  city  | country |     state     |      unit
    ----------+------------+---------+--------+---------+---------------+-----------------
    1         | DEVONSHIRE | PLACE   | BOSTON | USA     | MASSACHUSETTS | # PENTHOUSE 301

Using tables packaged with tiger geocoder. This example only works if you installed `postgis_tiger_geocoder`.

    SELECT *  FROM standardize_address('tiger.pagc_lex',
             'tiger.pagc_gaz', 'tiger.pagc_rules', 'One Devonshire Place, PH 301, Boston, MA 02109-1234');

Make easier to read we'll dump output using hstore extension CREATE EXTENSION hstore; you need to install

    SELECT (each(hstore(p))).*
     FROM standardize_address('tiger.pagc_lex', 'tiger.pagc_gaz',
       'tiger.pagc_rules', 'One Devonshire Place, PH 301, Boston, MA 02109') As p;

        key     |      value
    ------------+-----------------
     box        |
     city       | BOSTON
     name       | DEVONSHIRE
     qual       |
     unit       | # PENTHOUSE 301
     extra      |
     state      | MA
     predir     |
     sufdir     |
     country    | USA
     pretype    |
     suftype    | PL
     building   |
     postcode   | 02109
     house_num  | 1
     ruralroute |
    (16 rows)

Variant 2: As a two part Address

    SELECT (each(hstore(p))).*
     FROM standardize_address('tiger.pagc_lex', 'tiger.pagc_gaz',
       'tiger.pagc_rules', 'One Devonshire Place, PH 301', 'Boston, MA 02109, US') As p;

        key     |      value
    ------------+-----------------
     box        |
     city       | BOSTON
     name       | DEVONSHIRE
     qual       |
     unit       | # PENTHOUSE 301
     extra      |
     state      | MA
     predir     |
     sufdir     |
     country    | USA
     pretype    |
     suftype    | PL
     building   |
     postcode   | 02109
     house_num  | 1
     ruralroute |
    (16 rows)

#### See Also

stdaddr, rulestab, lextab, gaztab, Pagc_Normalize_Address