GIS Tutorial 1

1. GIS Tutorial 1 Lecture 7 Geocoding

2. Outline • Geocoding overview • Linear (street) geocoding • Problems and solutions • Street map sources • Polygon geocoding • Geocoding in ArcCatalog & ArcMap • Useful Web sites GIS TUTORIAL 1 - Basic Workbook

3. Lecture 7 Geocoding overview GIS TUTORIAL 1 - Basic Workbook

4. Geocoding • Process of creating geometric representations for locations (e.g., points) from descriptions of locations (e.g., street addresses) • Uses a computer program that employs code tables to standardize address components called a geocoding engine • Two ways to geocode • Batch geocoding—attempts to match all addresses • Interactive rematching—sophisticated user interface to match addresses GIS TUTORIAL 1 - Basic Workbook

5. Geocoding examples • City’s economic development department maps technology businesses by street addresses to see technology-rich areas in a city • County health director maps personal care and nursing homes and compares them to elderly population by neighborhood • Business maps store locations and compares to competitor locations • Emergency dispatch operators geocode an address to determine who should respond to an emergency call • Others? GIS TUTORIAL 1 - Basic Workbook

6. Geocoding files • Tabular data (text or dbase) • Street addresses • ZIP codes • Latitude and longitude GIS TUTORIAL 1 - Basic Workbook

7. Geocoding files • Geographic data • Street centerlines • ZIP code polygons GIS TUTORIAL 1 - Basic Workbook

8. Other geocoding files • Lines • Railroads, rivers • Polylines • Parcels, census blocks, tracts, MCD/CCDs, places, counties, etc. • Points • Landmarks such as churches, schools, and other cultural features represented as TIGER as points GIS TUTORIAL 1 - Basic Workbook

9. Lecture 7 Linear (street) geocoding GIS TUTORIAL 1 - Basic Workbook

10. Linear geocoding (streets) • Urban street maps • Four street address numbers ranging from low to high for each side of a street segment 198 100 Oak Street 199 101 GIS TUTORIAL 1 - Basic Workbook

11. Geocoding steps Original address: 125 East Oak Street 15213 Address parced: |125|East|Oak|Street| 15213 Abbreviations standardized: |125|E|Oak|St|15213 Elements assigned to match keys: [HN]:125 [SN]:Oak[ST]:St [SD]:E [ZP]:15213 Index values calculated: [HN]:125 [SN]:Oak(Soundex # ) [ST]:St [SD]:E [ZP]:15213 (Index #) GIS TUTORIAL 1 - Basic Workbook

12. Geocoding steps Candidates identified: 125 East Oak Street15213 Candidates scored and filtered: GIS TUTORIAL 1 - Basic Workbook

13. Geocoding steps Best candidate matched Oak St 198 98 100 2 101 1 199 99 123 Pine Av GIS TUTORIAL 1 - Basic Workbook

14. Address components Number123Oak St E, Apt. 2, Pittsburgh, PA 15213 Street name 123 Oak St E, Apt. 2, Pittsburgh, PA 15213 Street type 123 OakStE, Apt. 2, Pittsburgh, PA 15213 Direction, suffix 123 Oak St E, Apt. 2, Pittsburgh, PA 15213 Direction, prefix 123 EOak St, Apt. 2, Pittsburgh, PA 15213 Unit number 123 Oak St E, Apt. 2, Pittsburgh, PA 15213 Zone, city 123 Oak St E, Apt. 2, Pittsburgh, PA 15213 Zone, ZIP code 123 Oak St E, Apt. 2, Pittsburgh, PA 15213 Items for single number street address: Address Unit City ZIP Code 123 Oak St E Apt. 2 Pittsburgh 15213 GIS TUTORIAL 1 - Basic Workbook

15. Lecture 7 Problems and solutions GIS TUTORIAL 1 - Basic Workbook

16. Possible problems • Variations in street names • Fifth Avenue, Fifth Ave., 5th AV • Saw Mill Run Blvd, Route 51 • Data entry errors • Fidth Avenue • Sawmill Run • Place Names • White House, Heinz Field, Empire State Building • Intersections • Fifth Avenue and Craig Street GIS TUTORIAL 1 - Basic Workbook

17. Possible problems • Zones • 100 Main ST 15101, 100 Main ST 16202 • P.O. boxes • P.O. Box 125 • Missing street (TIGER) information GIS TUTORIAL 1 - Basic Workbook

18. Solutions • Clean data before geocoding • Use postal address standards • Publication 28 of the U.S. Post Office (2000) • Ultimate source on mailing address formats and codes • Provides standard street address formats • Standards include house number, prefix directional, street name, street suffix, common unit designator abbreviation for apartment, city, state abbreviation, five-digit ZIP code, ZIP+4 extension • Use Standard Intersection Connectors • & | @ GIS TUTORIAL 1 - Basic Workbook

19. Solutions • Use alias tables • Assign house numbers in rural areas • Purchase or build high quality maps (field verification) GIS TUTORIAL 1 - Basic Workbook

20. Lecture 7 Street map sources GIS TUTORIAL 1 - Basic Workbook

21. TIGER/Line files • 2000 Census street centerlines GIS TUTORIAL 1 - Basic Workbook

22. TIGER/Line files GIS TUTORIAL 1 - Basic Workbook

23. TIGER/Line files GIS TUTORIAL 1 - Basic Workbook

24. Street Map USA GIS TUTORIAL 1 - Basic Workbook

25. GDT Dynamap/2000 U.S. street data • Small fee for individual ZIP code layers • Map layers are the highest quality street-map layers in terms of appearance, completeness, and accuracy • Maps include more than 14 million U.S. street segments and include postal boundaries, landmarks, water features, and other features GIS TUTORIAL 1 - Basic Workbook

26. Lecture 7 Polygon geocoding GIS TUTORIAL 1 - Basic Workbook

27. Polygon geocoding • Method to map data whose identifier is a polygon (e.g. ZIP code, city, parcel identifier- ppn, or county) • Create an aggregate table with a single record for each unique polygon • Count the records for each polygon • Join table to corresponding polygon layer • Symbolize with a choropleth map or graduated point symbols GIS TUTORIAL 1 - Basic Workbook

28. TIGER: Polygon topology • ZIP codes • American Indian Reservation • Alaska Nature Village Statistical Area • Tribal Designated Statistical Area • Tribal Jurisdiction Statistical Area • Alaska Nature Regional Corp. • FIPS State and County Codes • MCD • Place • Census tract/block groups/blocks GIS TUTORIAL 1 - Basic Workbook

29. Polygon geocoding (ZIP codes) GIS TUTORIAL 1 - Basic Workbook

30. Polygon geocoding (ZIP codes) • Points created at ZIP code centroids GIS TUTORIAL 1 - Basic Workbook

31. Polygon geocoding (ZIP codes) • Spatially join points to polygons to make choropleth map GIS TUTORIAL 1 - Basic Workbook

32. Choropleth map result GIS TUTORIAL 1 - Basic Workbook

33. Lecture 7 GEOCODING IN ARCCATALOG GIS TUTORIAL 1 - Basic Workbook

34. Create address locator • ArcCatalog GIS TUTORIAL 1 - Basic Workbook

35. Choose address locator style • Skeleton of the address locator • Based on data tables and reference layer GIS TUTORIAL 1 - Basic Workbook

36. Choose reference layer • Streets, ZIP codes GIS TUTORIAL 1 - Basic Workbook

37. Address locator properties GIS TUTORIAL 1 - Basic Workbook

38. Geocode in ArcMap • Add tabular data and streets layer • Add address locator • Geocode addresses • View geocoding results • Interactively rematch addresses GIS TUTORIAL 1 - Basic Workbook

39. Address rematching • Investigate unmatched addresses • Generally requires expertise with knowledge of local streets • Compare street name in the attributes of streets table and address table GIS TUTORIAL 1 - Basic Workbook

40. Prepare log file • Log file includes reasons why addresses did not geocode • Useful for future work on cleaning addresses or repairing street maps GIS TUTORIAL 1 - Basic Workbook

41. Lecture 7 Useful websites GIS TUTORIAL 1 - Basic Workbook

42. Useful Web sites • http://www.usps.gov/ • http://www.geocode.com/geocode.htm • http://www.batchgeocode.com/ • http://www.mapquest.com • http://maps.google.com • http://www.zipinfo.com • http://zipskinny.com/ • http://www.semaphorecorp.com/cgi/zp4.html GIS TUTORIAL 1 - Basic Workbook

43. Summary • Geocoding overview • Linear (street) geocoding • Problems and solutions • Street map sources • Polygon geocoding • Geocoding in ArcView • Useful Web sites GIS TUTORIAL 1 - Basic Workbook