1. Chapter 10
Geocoding

2. Outline
What is geocoding?
Geocoding styles

3. What is geocoding?
The matching of a location stored in a table to a spatial point feature based on a reference spatial data layer, most often applied to converting addresses to locations.
Similar to an attribute join of a standalone table to an attribute table of a spatial data set, except
It can use multiple fields to match records
It can match records that are similar but not exactly the same
The spatial data set is called the reference layer

4. Geocoding applications
911 emergency response,
Map Quest and Google Earth,
Finding locations of customers,
Marketing analysis,
Mapping distribution of crimes, and
Mapping township/range descriptions.

5. Match an address to a street
The reference layer contains information about the street names and address ranges.
Each address in a table is matched to a location on a particular street.
Creates a point layer of addresses.
Address table
Reference layer

6. Matching addresses to points or polygons
Parcel reference layer

7. “Fuzzy” matching Joins and queries are based on exact matches
Geocoding is able to match records when values may be close but not identical
525 Mt Rushmore Rd
525 Mt. Rushmore Road
525 Mount Rushmore Rd.
525 Mt Rushmore
Address to match
Candidates

8. Using geocoding to join
Because geocoding relies on scoring candidates, rather than exact matching, it can be useful for joining tables lacking a single common field
Case does not match
City/state in two fields
Same name in multiple states
These two tables can’t be joined, but they can be matched.

9. Requirements
A reference layer, which is a shapefile or feature class containing features with attributes for matching
An address locator set up for the reference layer with rules and options
A table with address records to be matched

10. Address geocoding
Addresses to be matched are parsed into separate components (number, street name, etc.)
Each component is compared to the same fields in the reference layer
Candidates are scored based on closeness of matches (0-100)
is a good match

11. Address components Prefix direction. 124 East Main St.
Prefix type Highway 85.
Number Maple St.
Street name Maple St.
Street type Maple St. or 15 Elm Ct
Suffix direction. Florman St. E or 87th St. North
City, State, Zip code. Optional

12. How addresses are parsed
Prefix Dir
Prefix Type
Num-ber
Street
Type
Suffix Dir
123 Maple Road
123
MAPLE RD
15 Center St. East 15
CENTER ST E
314 Hwy 85 N
HWY
314 85 N
234 E. St. Patrick St.
234
SAINT PATRICK
Notice that parsing includes converting to upper case.

13. Reference layer 3120 NORTHLAND DR
Point, line, or polygon features with attributes on which matching will be based

14. Placing addresses 750 Meadowlark From: To: 700 799 } Offset
Meadowlark St.
From:
700
To:
799
750 Meadowlark
725 Meadowlark
} Offset

15. Geocoding Styles Single Field US Alphanumeric Ranges
US Cities with State
US One Address
US One Range
US Streets
US Hyphenated
World Cities with Country
ZIP 5-Digit and ZIP+4
With Zone

16. US Streets Style
Locates street address on both sides of the street using a line reference layer.
Requires address ranges on both left and right side of streets.

17. US One Range Style
Similar to US Streets but does not consider left or right sides.
Requires a single address range for each street.

18. One Address Style
Matches a single field address to a single point or polygon.
Most often used with parcel data.

19. City State Style
Matches two fields containing a city name and a state name or abbreviation.
Must match to points or polygons.

20. PLSS Coding Public Land Survey System Plotted on topographic maps
Common in many states for recording locations
Township = 36 sections
Section = 1 mi2 = 640 acres
Each section is divided into quarters: NW, NE, SW, SE.
Each ¼-section is divided into 4 more quarters (40 acres).
T15S, R28E, S6, NW,NW

21. TSR geocoding Townships for Grant County, Oregon
Sample localities in TRS format
Calculated key
Townships for Grant County, Oregon
Locate geologic samples based on TSR

22. References Price, M. (2013). Mastering ArcGIS (6th ed.). McGraw-Hill
Price, M. (2013). Mastering ArcGIS (6th ed.). McGraw-Hill. Mastering ArcGIS, 6/e Instructor Edition Chapter 10: PowerPoint Notes and Figures