GIS Tutorial 1 Lecture 7 Geocoding Outline u

GIS Tutorial 1 Lecture 7 Geocoding

Outline u u u u Geocoding overview Linear (street) geocoding Problems and solutions Street map sources Polygon geocoding Geocoding in Arc. View Useful Web sites GIS TUTORIAL 1 - Basic Workbook 2

Lecture 7 GEOCODING OVERVIEW GIS TUTORIAL 1 - Basic Workbook 3

Geocoding u u u 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 4

Geocoding examples u u u 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 5

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

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

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

Lecture 7 LINEAR (STREET) GEOCODING GIS TUTORIAL 1 - Basic Workbook 9

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

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 11

Geocoding steps Candidates identified: 125 East Oak Street 15213 From To Street Type Side Parity Direction Street_ 2 98 Oak St R E W 4344 1 99 Oak St L O W 4345 100 198 Oak St R E E 4346 101 199 Oak St L O E 4357 Candidates scored and filtered: From To Street Type Side Parity Direction Street_ 100 198 Oak St R E E 4346 101 199 Oak St L O E 4357 GIS TUTORIAL 1 - Basic Workbook 12

Geocoding steps Best candidate matched From To Street Type Side Parity Direction Street_ 101 199 Oak St L O E 4357 Oak St 98 100 198 1 99 101 199 Pine Av 2 GIS TUTORIAL 1 - Basic Workbook 123 13

Address components Number 123 Oak St E, Apt. 2, Pittsburgh, PA 15213 Street name 123 Oak St E, Apt. 2, Pittsburgh, PA 15213 Street type 123 Oak St E, Apt. 2, Pittsburgh, PA 15213 Direction, suffix 123 Oak St E, Apt. 2, Pittsburgh, PA 15213 Direction, prefix 123 E Oak 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 123 Oak St E GIS TUTORIAL 1 - Basic Workbook Unit City ZIP Code Apt. 2 Pittsburgh 15213 14

Lecture 7 PROBLEMS AND SOLUTIONS GIS TUTORIAL 1 - Basic Workbook 15

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

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

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

Solutions u Use alias tables Alias Address White House 1600 Pennsylvania Avenue Heinz Field 100 Art Rooney Avenue Empire State Building 350 5 th Ave u u Assign house numbers in rural areas Purchase or build high quality maps (field verification) GIS TUTORIAL 1 - Basic Workbook 19

Lecture 7 STREET MAP SOURCES GIS TUTORIAL 1 - Basic Workbook 20

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

TIGER/Line files GIS TUTORIAL 1 - Basic Workbook 22

TIGER/Line files GIS TUTORIAL 1 - Basic Workbook 23

Street Map USA GIS TUTORIAL 1 - Basic Workbook 24

GDT Dynamap/2000 U. S. street data u u u 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 25

Lecture 7 POLYGON GEOCODING GIS TUTORIAL 1 - Basic Workbook 26

Polygon geocoding u Method to map 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 GIS TUTORIAL 1 - Basic Workbook 27

TIGER: Polygon topology u u u u u 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 28

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

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

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

Choropleth map result GIS TUTORIAL 1 - Basic Workbook 32

Lecture 7 GEOCODING IN ARCVIEW GIS TUTORIAL 1 - Basic Workbook 33

Create address locator u Arc. Catalog GIS TUTORIAL 1 - Basic Workbook 34

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

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

Address locator properties GIS TUTORIAL 1 - Basic Workbook 37

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

Address rematching u 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 39

Prepare log file u u Log file includes reasons why addresses did not geocode Useful for future work on cleaning addresses or repairing street maps Incorrect address Possible reason/solution 490 Penn Avenue Missing ZIP code 111 Hawksworth Spelled incorrectly 900 Smallman Street TIGER street missing 900 Lib Ave Spelled incorrectly GIS TUTORIAL 1 - Basic Workbook 40

Lecture 7 USEFUL WEBSITES GIS TUTORIAL 1 - Basic Workbook 41

Useful Web sites u 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/ u Others? u u u GIS TUTORIAL 1 - Basic Workbook 42

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