Session: Parcel/Address Data MaintenanceHow Addresses Are Used in GIS

Presenter:Wade Kloos, ESRI

Date: Thursday, October 4, 2001

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How Addresses Are Used In GIS

Addresses can be used to join or relate GIS data to other agency databases (police, sales-tax and other non-APN based datasets)

Addresses are valuable attributes for

managing GIS features (parcels,

businesses, utilities,etc.)

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The Search for Map Position

GEOCODING also called

ADDRESS MATCHING

Depicting the relationship of a record’s address to a mapped street feature.

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GeoCoding – How It Works

Interpolating Process Compares a record’s address attribute to

the address range of a mapped feature – a road.

100 Main St. 200

101 199

170 Main St.

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123 Main Street 100-200 Main St. 95 123 Maine St. 100-200 Main St. 80 123 Mane Rd. 100-200 Main St. 50/DNP 99 Main St. 100-200 Main St. DNP

Scoring GeoCoded Matches

Example: Record Range Score

The GeoCoding process assigns a match score to each address –if the match score is over a certain threshold, the program will map the record.

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GeoCoding – Not an Exact Science

Placement can be affected by: Inconsistencies of data entry process Subtleties of the GeoCoding scoring methods The interpretive process itself Land use patterns

However, GeoCoding is useful when address data is less than perfect

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Another Address Location Option

ISSUES:Not a Batch Process – unless custom scripts are builtNo tolerance for dissimilar addresses – no interpolationOnce matched, placement is as accurate as features are mapped

Direct queries against GIS feature databases - Polygons and Points

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Based on parcel polygon attributes

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Based on point feature attributes

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Database Conventions

To maximize usefulness of address information, a database should have the several data fields, including but not limited to:

Street Number (numerical/alphanumeric)Street NameStreet Name PrefixStreet Name SuffixUnit Number (residential apt. or condo)Suite Number (businesses)Address – combo of number, street, suffix, etc.City ZipZip + 2,4

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Database Standards

Standardization of addressing syntax is critical for consistent search results and integration with other application databases.

Develop and adopt a master address database - from USPS or existing city databases – both of which requires QC by staff

Every field needs to be QC

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Database Standards

1st vs. First E. Ball vs. East Ball Avenida del Caballo vs. Ave. Del Caballo King Court vs. King Ct

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Using GIS to QC Address Data

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Using GIS to QC Address Data