NCGIA Core Curriculum in Geographic Information Science
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Unit 016 - Discrete Georeferencing

by David J. Cowen, Department of Geography, University of South Carolina, Columbia, USA

This section was edited by Kenneth Foote, Department of Geography, University of Texas Austin.

This unit is part of the NCGIA Core Curriculum in Geographic Information Science. These materials may be used for study, research, and education, but please credit the author, David J. Cowen, and the project, NCGIA Core Curriculum in GIScience. All commercial rights reserved. Copyright 1997 by David J. Cowen.

Your comments on these materials are welcome. A link to an evaluation form is provided at the end of this document.

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Unit 016 - Discrete Georeferencing

1. Georeferencing (or Geocoding)

 1.1. Example of Georeferencing

The Palmetto Seafood Company
2200 Gervais Street
Columbia, SC 29204-1808 USA
Address Feature Description Figures
USA Country Figure 1
292 Three digit ZIP-Code Area Figure 2.
29204 Five digit ZIP-Code Area Figure 3.
29204-18 ZIP Plus 2 Area Figure 4.
29204-1808 ZIP Plus 4 Point Figure 5.
SC State Figure 6.
Columbia City Figure 7.
The postal definition of Columbia  Group of ZIP Areas Figure 8.
2200 Gervais Street Street Address Figure 9
The UTM Coordinates  X, Y Coordinate pairs  Figure 10.
The Palmetto Seafood Company Name of Business Figure 11.

1.2. Georeferencing Applications

2. Georeferencing Methods

2.1. Direct Survey and property boundaries

2.2. Simple Database Queries

2.3. Specialized Georeferencing Options

 2.3.1. Single Field

2.3.2. Zip Code Address Style

2.3.3. US Streets Address Style

2.3.4. Single Range

3. Problems With Address Records

3.1. Handling Address Errors

3.2. ArcView™ Example

3.2.1. Spelling Sensitivity

3.2.2. Minimum Match Score

3.2.3. Minimum Score to be Considered a Candidate

3.3. Examples

3.3.1. Example 1

Address Score
2200 Gervais St 100
Figure 23. 2200 Gervaiss St 91 
2200 Gervais Dr 75
2200 Gerv St  72
2200 N. Gervais St  52
Address Score
Gervais 100
Gregg 57
Green 57

3.3.2. Example 2

Address Score
2210 Gervais St 85
2221 Gervais St 70
2200 Gervais St 70
2010 Gervais St  70
2100 Gervais St 53
2229 Gervais St 40

3.4. Limitations of Georeferencing

4. Sources of Basemaps for Georeferencing

4.1. Bureau of the Census

4.2. Other Suppliers

5. Sources of Address Data

5.1. Digital Yellow Pages

5.1.1. Web Based

5.1.2. CD-ROM Based

5.2. Demographic and Marketing firms

6. Review and Study Questions

7. Reference Materials

7.1. Print References

Berry, Joseph K. 1996. "Spatial Objects--Parse and Parcel of a GIS?," GIS World. October: Vol.9, No.10, p. 28.

Cooke, Donald F. 1993. "TIGER 1992 Version Scheduled to Arrive," GIS World. May, Vol.6, No.5. p. 61.

Cooke, Donald, 1997. "Understanding Geodemographics," Business Geograpics, Vol.5, No.1, p. 32.

Halls, Joanne. 1994. "Address-Matching Using U.S. Postal Service Zip+4", Proceedings. ESRI Users Conference.

Lange, Art. 1996. "Georeferencing Basics Lead to Accurate GIS Data" GIS World, December, Vol. 9, No.12, p. 106.

Raper, J., D. Rhind, and J. Sheperd. 1992 Postcodes: The New Geography, Essex:
Longman Scientific.

Marx. 1990. The TIGER system: Yesterday, Today and Tomorrow, Cartography and GIS Vol. 17, No.1, pp. 89-97. (This volume of CAGIS was dedicated to TIGER)

Thrall, Grant, J. del Valle, and S. Elshaw-Thrall. 1995. "Business GIS Data Part 6: When is Zip+2 Geocoding Good Enough?,"Geo Info Systems, Vol.5, No.11, p. 40.

Thrall, Grant, J. del Valle, and S. Elshaw-Thrall. 1994 "Shop Talk: Business GIS Data, Part Three Zip plus 4 Geocoding," Geo Info Systems, Vol. 4, p. 57.

Van Demark, Peter. 1993. "City Tailors GIS to Address Information Needs," December: Vol.6, No.12, p. 50.

Van Demark, Peter. 1993. "TIGER Massage Expands TIGER FILE FUNCTIONALITY," GIS World, August: Vol. 6, No.8, p. 62.

7.2. Web References

7.3. Glossary


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Cowen, David J. (1997) Discrete Georeferencing, NCGIA Core Curriculum in GIScience,, posted February 11, 1997.

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Created: February 11, 1997.  Last revised: December 18, 1997.

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