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Introduction to Geographic Information Systems Spring 2013 (INF 385T-28437) Dr. David Arctur Lecturer, Research Fellow

Introduction to Geographic Information Systems Spring 2013 (INF 385T-28437) Dr. David Arctur Lecturer, Research Fellow University of Texas at Austin Lectures 8 & 9 Feb 28, 2013 8 - Spatial Analysis 9 - Geocoding. Geocoding Outline (Tutorial Ch.7). Geocoding overview

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Introduction to Geographic Information Systems Spring 2013 (INF 385T-28437) Dr. David Arctur Lecturer, Research Fellow

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  1. Introduction to Geographic Information Systems Spring 2013 (INF 385T-28437) Dr. David Arctur Lecturer, Research Fellow University of Texas at Austin Lectures 8 & 9 Feb 28, 2013 8- Spatial Analysis 9 - Geocoding

  2. Geocoding Outline (Tutorial Ch.7) INF385T(28437) – Spring 2013 – Lecture 9 Geocoding overview Linear (street) geocoding Problems and solutions Street map sources Polygon geocoding Geocoding in ArcGIS Useful Web sites

  3. Lecture 9 Geocoding overview INF385T(28437) – Spring 2013 – Lecture 9

  4. Geocoding INF385T(28437) – Spring 2013 – Lecture 9 • 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

  5. Geocoding examples INF385T(28437) – Spring 2013 – Lecture 9 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?

  6. Geocoding files • Tabular data (text or dbase) • Street addresses • ZIP codes • Latitude and longitude INF385T(28437) – Spring 2013 – Lecture 9

  7. Geocoding files INF385T(28437) – Spring 2013 – Lecture 9 • Geographic data • Street centerlines • ZIP code polygons

  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 INF385T(28437) – Spring 2013 – Lecture 9

  9. Lecture 9 Linear (street) geocoding INF385T(28437) – Spring 2013 – Lecture 9

  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 INF385T(28437) – Spring 2013 – Lecture 9

  11. Geocoding steps Original address: 125 East Oak Street15213 Address parsed: |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 #) INF385T(28437) – Spring 2013 – Lecture 9

  12. Geocoding steps Candidates identified: 125 East Oak Street15213 Candidates scored and filtered: INF385T(28437) – Spring 2013 – Lecture 9

  13. Geocoding steps Best candidate matched Oak St 198 98 100 2 101 1 199 99 123 Pine Av INF385T(28437) – Spring 2013 – Lecture 9

  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 INF385T(28437) – Spring 2013 – Lecture 9

  15. Lecture 9 Problems and solutions INF385T(28437) – Spring 2013 – Lecture 9

  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 INF385T(28437) – Spring 2013 – Lecture 9

  17. Possible problems • Zones • 100 Main ST 15101, 100 Main ST 16202 • P.O. boxes • P.O. Box 125 • Missing street (TIGER) information INF385T(28437) – Spring 2013 – Lecture 9

  18. Solutions INF385T(28437) – Spring 2013 – Lecture 9 • 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 • & | @

  19. Solutions INF385T(28437) – Spring 2013 – Lecture 9 • Use alias tables • Points of Interest (POI) databases; gazetteers • Assign house numbers in rural areas • Purchase or build high quality maps (field verification)

  20. Lecture 9 Street map sources INF385T(28437) – Spring 2013 – Lecture 9

  21. Caution: source has changed TIGER/Line files INF385T(28437) – Spring 2013 – Lecture 9 2000 Census street centerlines

  22. Caution: source has changed TIGER/Line files INF385T(28437) – Spring 2013 – Lecture 9

  23. Commercial sources for maps INF385T(28437) – Spring 2013 – Lecture 9 • GDT / ETAK / TeleAtlas TomTom.com • All the big pioneers of streetmaps are now TomTom • EsriStreetMap Premium for ArcGIS • No more free streetmaps • MapBox.com (free & fee) • Others…?

  24. OpenStreetMap.org (free open-source) INF385T(28437) – Spring 2013 – Lecture 9

  25. Lecture 9 Polygon geocoding INF385T(28437) – Spring 2013 – Lecture 9

  26. Polygon geocoding INF385T(28437) – Spring 2013 – Lecture 9 • Suppose you wished to make a choropleth map showing distribution of attendees at an event • Need to geocode data whose identifier is a polygon (e.g. ZIP code, city, 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

  27. Polygon geocoding (ZIP codes) INF385T(28437) – Spring 2013 – Lecture 9

  28. Polygon geocoding (ZIP codes) INF385T(28437) – Spring 2013 – Lecture 9 Points created at ZIP code centroids

  29. Polygon geocoding (ZIP codes) INF385T(28437) – Spring 2013 – Lecture 9 Spatially join points to polygons to make choropleth map

  30. Choropleth map result INF385T(28437) – Spring 2013 – Lecture 9

  31. Lecture 9 Geocoding in Arcgis INF385T(28437) – Spring 2013 – Lecture 9

  32. Create address locator INF385T(28437) – Spring 2013 – Lecture 9 ArcCatalog

  33. Choose address locator style INF385T(28437) – Spring 2013 – Lecture 9 Skeleton of the address locator Based on data tables and reference layer

  34. Choose reference layer INF385T(28437) – Spring 2013 – Lecture 9 Streets, ZIP codes

  35. Address locator properties INF385T(28437) – Spring 2013 – Lecture 9

  36. Geocode in ArcMap INF385T(28437) – Spring 2013 – Lecture 9 Add tabular data and streets layer Add address locator Geocode addresses View geocoding results Interactively rematch addresses

  37. Address rematching INF385T(28437) – Spring 2013 – Lecture 9 • Investigate unmatched addresses • Generally requires expertise with knowledge of local streets • Compare street name in the attributes of streets table and address table

  38. Prepare log file INF385T(28437) – Spring 2013 – Lecture 9 Log file includes reasons why addresses did not geocode Useful for future work on cleaning addresses or repairing street maps

  39. Lecture 9 Useful websites INF385T(28437) – Spring 2013 – Lecture 9

  40. Useful Web sites • http://www.usps.gov/ • http://www.geocode.com/(TomTom fee service) • http://batchgeo.com/ • http://www.mapquest.com • http://maps.google.com • http://www.bing.com/maps/ • http://www.zipinfo.com • http://zipskinny.com/ • Others? INF385T(28437) – Spring 2013 – Lecture 9

  41. Geocoding Summary INF385T(28437) – Spring 2013 – Lecture 9 Geocoding overview Linear (street) geocoding Problems and solutions Street map sources Polygon geocoding Geocoding in ArcView Useful Web sites Complete Assignment 7-1 (7-2 optional)

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