Welcome to Address Databases

1. Welcome to Address Databases Learon Dalby Arkansas Geographic Information Office Little Rock, Arkansas R. Brian Culpepper Center for Advanced Spatial Technologies Fayetteville, Arkansas MidAmerica GIS Symposium2002 Kansas City, Missouri

2. Today’s Schedule • Sunday April 14, 2002 • 1:00pm - 5:00pm • 2, 15 minute breaks • Outline for Lecture

3. General Information • Location of Rest Rooms • Schedule and Breaks • Emergency Information

4. Addressing Workshop Agenda • Introduction to Addressing Methods • Rural Address Procedural Overview • Urban Address Issues • Geographic Base Files Overview • Graphic Data Clean-up Issues • Database Management Issues • Student Experiences/Future Plans

5. Why are we interested in Address Databases? • Locate Citizen Complaints • Emergency Response • Permit Enforcement • Incident Mapping • 911

6. Address Database issues vary.. • Dependent upon your proposed task or service. • Are you in a rural county and starting from scratch? • Are you in an established city with 120 yrs of addresses assigned without any STANDARDS?

7. Before Starting any Address or GIS project: • Develop an effective plan • What questions need to be answered with these data or systems? • Know the condition of your data. • Chart how you want to get from the start to finish. • Understand the capabilities of the software you will be using. • Know the limitations and strengths of the GIS/911 software • Know the limitations and strengths of the database software. • Complete Pilot Project before full roll-out of any new system. • Understand the capabilities of your staff, co-workers, and other partners.

8. Quick Review of GeoCoding Methods and Types of Locations

9. Some Geocoding Definitions • Address Geocoding - Assigning X,Y coordinates to tabular data such as street addresses or zip codes so that they may be displayed as points on a map. • Address Parity - Evenness or oddness. In address geocoding, parity is used to locate an address on the correct side of the street. • Such as, odd numbers on the left side; even on the right...

10. Street Address Locations (Lines) • Single-Field Range Geocoding Style • Dual Range (with Parity) Address Geocoding • Street Centerlines are typically attributed with corresponding Address Ranges and Street Name.

11. Zip Code Locations (Points) • Postal Codes such as 5-digit zip codes can be matched with address databases. • The centroid of the Zip Code area may be used to determine the X,Y coordinate. • Interpolation of +4 Zip Codes along street centerlines

12. Place Names or Addresses (Polygons) • Tax Assessor or Parcel Databases • Place Names such as City or State names may also be used to “Locate” non-graphic attribute records. • Map labels are common “Locators” for other data.

13. The Postal Address • Single most common form of geographic information • May be “geocoded” to an X,Y coordinate location using a “Locator File” containing points, lines or polygons with similar address “ranges” or attributes. • Street Centerlines are “interpolated” based upon Address Range (and Parity) to determine a single X, Y location.

14. Locating Addresses • Place Names, Buildings (or Vanity Addresses) are located by linking the non-graphic table to the “spatially referenced” or graphic data. • Correct Spelling and/or sensitivity settings are important when “matching attributes.” • Street intersections are also common “Locators”

15. Geographic Base FilesAn overview

16. Geographic Base Files • Definition of the GBF • A Conceptual Overview • DIME File History and Structure • TIGER/Line Files Addressing Structure • Value Added TIGER

17. Geographic Base Files • A database of files containing cartographic and attribute information such as boundaries of geographic areas, address ranges, and street intersections. • The most common GBF’s are DIME files and TIGER files. • DIME - Dual Independent Map Encoding. Developed for the 1970 and 1980 Census • TIGER - Topologically Integrated Geographic Encoding and Referencing. Developed for the 1990 Census.

18. Geographic Base Files • May also be a referenced file containing geographic coordinates to be used for non-geographic data. • Typically these files attributes include: • street names / intersections • address ranges per street segment • census tract numbers • geographic coordinates • zip code centroids, political districts, etc.

19. Uses of Geographic Base Files • Records from an non-graphic database are linked to the matching record in the geographic database (GBF) in order to define “some” geography for that record. • Geo-coding is a common term for this process. Linking a “non-spatial object ” to a “spatial object”.

20. Conceptual Use of a GBF Non-Graphic Data Non-Graphic Data with Geocodes Geocoding Program Geographic Base Files

21. Types of Geographic Base Files DIME files • Dual Independent Map Encoding (DIME) files were first created in 1970 by the U.S. Census Bureau. • DIME used for 1980 Census Data Collection. • Flat File Structure • Data update problems and only about 2% coverage of the United States.

22. DIME/GBF “Generic” Structure • Each record contains both even and odd address geography. • Contained both lat./long and State Plane Coordinates • Nodes that formed Areas were ‘tagged’ with a unique ID. DB columns

23. 34580 Malcolm Ct.. Heath Ave. BLOCK #6 BLOCK #7 L20 L22 1198 1100 1098 1020 P16 P14 1199 1101 1099 Gadberry Dr. 1021 P15 BLOCK #10 34581 Big John St. Basic GBF File Structure • What the Geographic Base File represents. • An Abstraction of Reality (street networks)

24. BLOCK #6 BLOCK #7 L20 L22 1198 1100 1098 1020 P16 P14 1199 1101 1099 Gadberry Dr. 1021 P15 GBF Basic Concepts GBF FILE (a Flat File) GBF FILE (Graphic Example) The GBF contains “Ranges” of potential addresses and “Lists” of corresponding Street Segments.

25. Conceptual Geocoding Workflow Non-Graphic Data with Geocodes Non-Graphic Data Geocoding Program Geographic Base Files

26. Geocoding Workflow Non-graphic Geocoding Program GBF Table Geocoded

27. Another Common Geographic Base File TIGER/Line Files • Acronym for Topologically Integrated Geographic Encoding and Referencing. • TIGER 1989 to Present • Relational Database Structure (Map data and attributes). • > 50 Million geographic features that are fully integrated with the census data. • Incorporated DIME and USGS Digital Line Graph (dlg) paper map products (1:100k). • Complete coverage of the United States.

28. What is topology? • Topological data structures tell the computer which cartographic objects are connected to each other logically. • It defines how points, lines and polygons are related to each other on the map - an implicit relationship that is obvious to the human eye, but not explicitly defined by cartographic records within the computer.

29. Geographic Elements used for defining topological data structures • Points - zero-dimensional objects on a map which represent a single location on the earth. • Examples: • Street Intersections • Water Valves • Addresses • Fire Hydrants

30. Geographic Elements used for defining topological data structures • Lines: one-dimensional objects on a map which represent a linear feature having a beginning point and an ending point. Lines may be subdivided into smaller units called arcs to define curves. • Examples: • Street Centerlines • Lot Lines • Rivers

31. Geographic Elements used for defining topological data structures • Polygons: Two-dimensional objects which represent shapes which have area. Polygons can be displayed and manipulated as single objects. • Examples: • Census Blocks • Land Parcels • Zoning Districts

32. General Topologic Relationship Scheme Points Lines Polygons Unique ID Feature Type X coordinate Y coordinate Unique ID Feature Type Beginning Point Ending Point Unique ID Feature Type Boundary Lines Unique ID Feature Type X coordinate Y coordinate Unique ID Feature Type Beginning Point Ending Point Unique ID Feature Type X coordinate Y coordinate

33. TIGER topology: Terms and Descriptions • Node “A zero-dimensional object that is a topological junction of two or more links or chains, or an end point of a link or chain,” is a node. • Entity Point “A point used for identifying the location of point features (or areal features collapsed to a point), such as towers, buoys, buildings, places, etc.” • Complete Chain “A chain [a sequence of non-intersecting line segments] that explicitly references left and right polygons and start and end nodes.” • The shape points combine with the nodes to form the segments that make a complete chain. • Network Chains “A chain that explicitly references start and end nodes and not left and right polygons.” • GT-Polygon “An area that is an atomic two-dimensional component of a two-dimensional manifold, [which is defined as] one and only one planar graph and its two-dimensional objects.”

34. TIGER topology (example) • Nodes • Entity Points • Complete Chains • Network Chains • GT-Polygons

35. TIGER Line Files and Addresses • The TIGER/Line ® files contain address ranges, not individual addresses. • The term address rangerefers to the first possible structure number and the last possible structure number along a complete chain side, relative to the direction in which the complete chain is coded. • The address ranges are predominantly potential ranges that include the full range of possible structure numbers even though the actual structures might not exist.

36. TIGER Line Files and Addresses (continued) • The address numbers used to create the address ranges are commonly known as city-style addresses. • A city-style address minimally consists of a structure number, street name, and a 5-digit ZIP Code ® such as, 213 Main St 90210, but usually more info is provided. • Address range information is stored in two record types. Record Type 1 contains the basic complete chain attributes, including one basic address range. Record Type 6 stores the additional ranges when the complete chain has more than one range on one or both sides.

37. Basic characteristics of address ranges • The TIGER/Line ® files generally contain only those city-style address ranges used for mail delivery and do not show rural route or post office box addresses. • They may contain structure numbers assigned in select areas for use by local emergency services, but not for mail delivery. • Gaps may exist between multiple ranges for a single complete chain.

38. Basic characteristics of address ranges (continued) • In a few rare cases, address ranges can include numbers with alphabetic characters. These characters help uniquely identify addresses within a county. • For instance, certain unincorporated areas of Genesee County, Michigan add a letter G prefix to the address number. The characters are consistently placed within the address range field; for example, the letter G maintains a consistent column placement in the range G1 to G99. • Address ranges exist only for street features, and in some cases, corporate corridor and corporate offset boundary features.

39. Address Ranges • Complete chains in the TIGER/Line ® files have one end point labeled as the start node and the other end point labeled as the end node (also are referred to as from and to). • The start node always corresponds to the beginning of the complete chain identified by the start node coordinates FRLAT and FRLONG.

40. Address Ranges (cont.) • The order of the addresses follows the sequence of the nodes on the complete chain; the nodes may not be related to the low to high orientation of the address range. • The start address may be higher or lower than the end address for a complete chain. Structure numbers usually, but not always, systematically increase or decrease while moving along a street in a set direction from one complete chain to the next.

41. TIGER Address Range Example

42. Address Ranges and Impute Flag Codes Address Ranges • Numeric characters or a mixture of numeric and alphabetic characters (maximum of 11 characters) • Ranges beginning or ending with zero (0) are not valid Address range fields are blank when no address range is available. • Both the start and end address range fields are blank, or both have non-zero values. • The KGLADD field on Record Type 9 contains a “0” when KGL’s do not have a valid address. Impute Flags (1-character numeric code) • Blank— No address range available • 0— Not imputed • 1— Imputed

43. Address Ranges and Impute Flag Codes Limitations • Users of the address ranges in the TIGER/Line ® files should check for address range overlaps, gaps, odd/even reversals, and other situations that may be incorrect. While the Census Bureau continues to edit for, and correct these situations, it is possible that some still exist. Record Linkages • The TLID field links Record Types 1 and 6. Since a complete chain can have more than one set of address ranges, multiple Type 6 records can exist with the same TLID. The TIGER/Line ® files distinguish these records with a record sequence number (RTSQ). The files do not contain a field indicating whether a Type 6 record exists for a specific TLID; the user must scan any existing records in Record Type 6 for a TLID match.

44. Multiple and Out-of-Sequence Address Ranges

45. Address Range Special Cases

46. Imputed Address Ranges • Imputed address ranges occur during the process of updating the Census TIGER ® data base when a new complete chain intersects an existing complete chain with address ranges. • The intersection splits the existing complete chain and produces two new complete chains connected by a new node located at the intersection point. • The update program divides the old address ranges among the two new complete chains and imputes the address range ends at the new node. • The impute flags identify address ranges that have been through the impute process. • Each record in the TIGER/Line ® files contains four separate 1-character impute flag fields, one for each address range end.

47. Address Range Imputes -Before Split

48. Address Range Imputes -After Split

49. Address Range Record Locations Record Type Field Name Description 1 FRADDL Start Address, Left 1 TOADDL End Address, Left 1 FRADDR Start Address, Right 1 TOADDR End Address, Right 6 FRADDL Start Address, Left 6 TOADDL End Address, Left 6 FRADDR Start Address, Right 6 TOADDR End Address, Right 9 KGLADD Key Geographic Location Address

50. Impute Flag Record Locations Record Type Field Name Description 1 FRIADDL Start Imputed Address Flag, Left 1 TOIADDL End Imputed Address Flag, Left 1 FRIADDR Start Imputed Address Flag, Right 1 TOIADDR End Imputed Address Flag, Right 6 FRIADDL Start Imputed Address Flag, Left 6 TOIADDL End Imputed Address Flag, Left 6 FRIADDR Start Imputed Address Flag, Right 6 TOIADDR End Imputed Address Flag, Right