1. GTECH 709 Geocoding and address matching
What is a census?
Decennial census
Census geography framework

2. Geocoding
The process of assigning a location to an address by comparing the descriptive location elements in the address to those present in the reference material

3. Address Processing

4. Address Basics
What is an address?
Address elements
Address formats

5. Address Reference Systems
Axial
Based on a set of base lines that define the starting points for numbering
Often the basis for a “grid” type system
Linear Non-Axial
Numbering is based on the distance along a specific street
Where streets follow contours, change direction frequently
Area-based
Numbers assigned within a specified area by other method (example: mobile home parks, campgrounds)‏
May use lot numbers, chronological order, other

6. Address Grid Example Axis Lines Point of Beginning East 2000 East 3000
North 2000
Point of Beginning
North 1000
South 1000
South 2000
West 3000
West
West

7. Axial System
Starting Point
for address numbers

8. Linear Non-Axial System
Each street may be numbered starting at a specified location
Sometimes similar to State DOT: numbering begins at south or west end, ends at north or east end
May simply be defined locally
Most often found where there is significant topography, such as mountains, river deltas, other natural features that would make a grid or axial system impractical
Useful when streets change directions frequently due to topography or natural barriers

9. Linear Non-Axial System
Starting Point
for numbering

10. Requirements Creating an address locator Reference layer
Rules for assigning a location to an address
Reference layer
The address locator assigns addresses based on information in this layer

11. Using Addresses for Geocoding
A vague method used to describe a location
Addresses are matched against a data reference source that contains address information as well as spatial information (feature geometry)

12. Addresses
Come in a variety of formats

13. Address Elements Pre-modifier: Old North B Street
Pre-directional: North Main Street
Pre-type: Avenue A
Name: Main Street
Post-type: Main Street
Post-directional: Main Street North
Post-modifier: B Street Extended
Separator: Avenue of the Americas

14. Landmarks
A landmark is a named point or area that is prominent enough in the local landscape as to be publicly known
Landmark: Hunter College
Complete Landmark Name: North Building, Hunter College
Community: 123 Urbanization Los Olmos

15. Geocoding Workflow

16. Reference Data Needs to cover the same area as data to be geocoded
Needs to have adequate level of detail
Needs to be current
Needs to be standardized
Use standard abbreviations

17. Reference Data Source

18. Address Locators
A dataset that stores the address attributes, associated indexes, and rules that define the process for translating nonspatial descriptions of places, such as street addresses, into spatial features
An address locator contains a snapshot of the reference data used for geocoding, and parameters for standardizing addresses, searching for match locations, and creating output

19. Address Locators
Contain information including address attributes, indexes, and queries for geocoding
Path to the reference data source and address event table
Algorithms for standardizing address descriptions and matching them to the reference data
Parameters for:
reading address data
matching the address data to the reference data
creating output

20. Address Locator
Specifies the method to interpret a particular type of address input, relate it with the reference data and deliver a geocoded output
The rule base is a collection of files used to translate the address data into the desired output

21. Address Locator Properties

22. Data Organization Mapping of attributes Reference feature…
and it’s associated table
Mapping of attributes

23. Address (Event) Tables
Any supported tabular format
One field must specify an address

24. Interactive Matching

25. Unmatched Records

26. Recoding Options

27. Interactive Review Dialog

28. Interpolating Addresses

29. Address Data Standards
Existing and Proposed US Standards
FGDC (Federal Geographic Data Committee) ‏- Endorsed, In Use
USPS (U.S. Postal Service)‏ - In Use
NENA (National Emergency Number Association)‏ - Pending adoption