(address matching)

Address Matching or Geocoding is the process by which addresses in your records are compared to addresses in your street file or parcel layer. If a legitimate address is found a point is created and the record is successfully geocoded on the map. X and Y coordinates can also be used to geocode records by location but more often than not the location is based on a physical address.

The following is a list of common reasons why a record would not match properly based on an address:

1. Insufficient Address Information – a full address consists of a street number, street direction, street name, and street type. An example of a full address would be “154 E SMITH ST.” An example of an insufficient address would be “E SMITH ST.” Without a street number it is impossible to locate the record.

2. Improper Address Entry – commercial business names or common landmark names are not considered to be sufficient address information. Entries such as “Lincoln High School” or “McDonalds” can not be matched if there is more than one “Lincoln High School” or “McDonalds” in the area. A full address is always preferred. Some common names can be located with the use of an alias table but this further reduces accuracy.

3. Extraneous Information Present – records will not match if there is extraneous information present. An example would be “Near the house at 123 S HAMPTON LN.” In this example “Near the house at” makes the record unmatchable. In some cases this extraneous information can be removed with address fixes but still further reduces the accuracy of the application.

4. Outside of Address Range – if a record has a street number that falls outside of the address range found in the street file, it will not match. For example if a record contains “1255 W MELBOURNE AVE” and the street file only contains ranges up to 1200 for W MELBOURNE AVE, the record will not match. This means that either the ranges in the street file need to be corrected or the street number was incorrectly entered.

5. Street Does Not Exist – sometimes a full address will not match because the street does not exist in the street file. In this case the street name could have been entered improperly, the street is outside of the area, or the street needs to be added to the street file. In some cases new streets can be added to the street layer. However, this is typically the responsibility of the city or county GIS manager.

6. Intersection Delimiter Inconsistent – intersections will only match if the delimiter is consistent. An example of a proper intersection entry would be “W SMITH ST & N BIRD LN.” In this example the delimiter is “&.” The use of several intersection delimiters such as “&”, “And”, “/” or “At” in one record set can be dealt with but again, further reduce the accuracy of the application by allowing more room for error.

7. No Address Present – it is impossible to locate records with an empty address. In these cases it is probably best to go back and research an actual location. Sometimes reviewing the original student record, incident report, or dispatch entry is helpful.

8. PO BOX Present – a post office box is sufficient when mailing a letter. However, it is not useful for locating points on a map. This would be another case where researching a physical location would be helpful.

9. Street Name Misspelled – sometimes records are rejected during the address match process because the street name is misspelled. Many of these misspellings can be handled with address fixes during the import process. However, this is sometimes subject to interpretation and spelling errors should be corrected by the records management system before geocoding takes place.

10. More Than One Match – the presence of the same street name in two different areas can also cause matching problems. In these cases it is usually best geocode the records with additional location information such as a zip code.

11. Multiple Name Entry – in some areas Spanish street names such as “VIA DEL REY” or “AVENIDA DEL TORO” are common. In such cases working with the address standardization and spelling sensitivity during the geocoding process is helpful in matching these records. On occasion the street file requires some editing. This is typically the responsibility of the city or county GIS manager.

Sources: WikiPedia and Omega Help Documents

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