GIS Lecture 8: Geocoding

Transcription

1 GIS Lecture 8: Geocoding 100 Elm Street GIS 1

2 Outline Geocoding Overview Linear (Street) Geocoding Problems and Solutions Polygon Geocoding Geocoding in ArcGIS GIS 2

3 Geocoding Overview GIS 3

4 Geocoding Address Matching - Process of creating geometric representations for locations (point features) from descriptions of locations (addresses) Displays tabular data containing addresses as points on a map Finds locations on a map easily GIS 4

5 Geocoding Examples Emergency dispatch operators geocode an address to determine who should respond to an emergency call 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 More? GIS 5

6 Source data Tabular data street addresses zip codes GIS 6

7 Destination data Geographic Data street centerlines zip code polygons GIS 7

8 Linear (Street) Geocoding GIS 8

9 Address Components Number 123 Oak ST E, Apt. 2, Pittsburgh, PA Street Name 123 Oak ST E, Apt. 2, Pittsburgh, PA Street Type 123 Oak ST E, Apt. 2, Pittsburgh, PA Direction, suffix 123 Oak ST E, Apt. 2, Pittsburgh, PA Direction, prefix 123 E Oak ST, Apt. 2, Pittsburgh, PA Unit Number 123 Oak ST E, Apt. 2, Pittsburgh, PA Zone, city 123 Oak ST E, Apt. 2, Pittsburgh, PA Zone, zip code 123 Oak ST E, Apt. 2, Pittsburgh, PA Items for Single Number Street Address: Address Unit City Zip Code 123 Oak ST E Apt. 2 Pittsburgh GIS 9

10 Linear Geocoding (Streets) Urban street maps -four street address numbers ranging from low to high for each side of a street segment. 100 Oak Street Left_from Left_to Right_from Right_to Street_name Type OAK ST GIS 10

11 Geocoding Steps Original Address: 125 East Oak Street Address Parced: 125 East Oak Street Abbreviations Standardized: 125 E Oak St Elements Assigned to Match Keys: [HN]:125 [SN]:Oak[ST]:St [SD]:E [ZP]:15213 GIS 11

12 Geocoding Steps Candidates Identified: 125 West Oak Street From To Street Type Side Parity Direction Street_ 2 98 Oak St R E W Oak St L O W Oak St R E E Oak St L O E 4357 Candidates Scored and Filtered: From To Street Type Side Parity Direction Street_ Oak St R E E Oak St L O E 4357 GIS 12

13 Major Geocoding Steps Best Candidate Matched From To Street Type Side Parity Direction Street_ Oak St R O E 4357 Oak St Pine Av GIS 13

14 Geocoding Flowchart GIS 14

15 Theoretical vs. Actual address ranges Lt_from Lt_to Rt_from Rt_to Lt_from Lt_to Rt_from Rt_to GIS 15

16 Problems and Solutions GIS 16

17 Possible Problems Variations in Street Names Fifth Avenue, Fifth Ave., 5th AV Saw Mill Run, Route 51 GIS 17

18 Possible Problems Variations in Street Names Fifth Avenue, Fifth Ave., 5th AV Saw Mill Run, Route 51 Data Entry Errors Fidth Avenue Sawmill Run GIS 18

19 Possible Problems Variations in Street Names Fifth Avenue, Fifth Ave., 5th AV Saw Mill Run, Route 51 Data Entry Errors Fidth Avenue Sawmill Run Place Names White House, Heinz Field, Empire State Building GIS 19

20 Possible Problems Variations in Street Names Fifth Avenue, Fifth Ave., 5th AV Saw Mill Run, Route 51 Data Entry Errors Fidth Avenue Sawmill Run Place Names White House, Heinz Field, Empire State Building Intersections 5th AV and Craig ST GIS 20

21 Possible Problems Variations in Street Names Fifth Avenue, Fifth Ave., 5th AV Saw Mill Run, Route 51 Data Entry Errors Fidth Avenue Sawmill Run Place Names White House, Heinz Field, Empire State Building Intersections 5th AV and Craig ST Zones 100 Main ST 15101, 100 Main ST GIS 21

22 Possible Problems Variations in Street Names Fifth Avenue, Fifth Ave., 5th AV Saw Mill Run, Route 51 Data Entry Errors Fidth Avenue Sawmill Run Place Names White House, Heinz Field, Empire State Building Intersections 5th AV and Craig ST Zones 100 Main ST 15101, 100 Main ST Post Office Boxes P.O. Box 125 GIS 22

23 Solutions Clean your data before geocoding Use postal address standards Publication 28 of the U.S. Post Office (2000) provides standard street address formats Use Standard Intersection Connectors GIS 23

24 Street Intersections Put street intersections in address field Forbes AV & Craig ST Grant ST & 5 th AV E North Star RD & Duncan AV Do not include street numbers 3999 Forbes Ave & 100 Craig ST Connectors Any unusual character (e.g., ) Just be consistent GIS 24

25 Solutions Use Alias Table Alias White House Heinz Field Empire State Building Address 1600 Pennsylvania Avenue 100 Art Rooney Avenue 350 5th Ave GIS 25

26 Other Geocoding Layers Polygons - parcels, census blocks, tracts, places, counties, etc. Points - landmarks such as churches, schools, and other cultural features represented as points GIS 26

27 Polygon Geocoding GIS 27

28 Polygon Geocoding Polygon features can be identified by their parcel numbers, postal zip, or zip+4 codes Parcel_Number (1046) ZIP (15218) ZIP + 4 ( ) GIS 28

29 Polygon Geocoding (Zip Codes) Points created at zip code centroids GIS 29

30 Polygon Geocoding (Zip Codes) Spatially join to make choropleth map GIS 30

31 Geocoding in ArcGIS GIS 31

32 Create Address Locator ArcCatalog GIS 32

33 Choose Address Locator style Skeleton of the Address Locator Based on data tables and reference layer GIS 33

34 Address Locator styles GIS 34

35 Choose reference layer Streets, ZIP Codes GIS 35

36 Address Locator parameters GIS 36

37 Geocode in ArcMap Add tabular data and streets layer Add your Address Locator Geocode addresses View geocoding results Interactively rematch addresses GIS 37

38 Address rematching Investigate unmatched addresses Generally requires expertise and knowledge of local streets. Compare a street name in the attributes of the streets table and the address table. GIS 38

39 Summary Geocoding Overview Linear (Street) Geocoding Problems and Solutions Polygon Geocoding Geocoding in ArcGIS GIS 39

40 * Tutorial 8 tip * don t worry if your geocoding Results are different percentages than shown in the book. if it tells you to Re-match a record that is already matched, just skip to the next step. GIS 40