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 Symposium 2002
Kansas City, Missouri
Today’s Schedule
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Sunday April 14, 2002
1:00pm - 5:00pm
2, 15 minute breaks
Outline for Lecture
General Information
• Location of Rest Rooms
• Schedule and Breaks
• Emergency Information
Addressing Workshop Agenda
• Introduction to Addressing Methods
– Rural Address Procedural Overview
– Urban Address Issues
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Geographic Base Files Overview
Graphic Data Clean-up Issues
Database Management Issues
Student Experiences/Future Plans
Why are we interested in Address Databases?
• Locate Citizen
Complaints
• Emergency Response
• Permit Enforcement
• Incident Mapping
• 911
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?
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.
Quick Review of GeoCoding
Methods and Types of Locations
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...
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.
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
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.
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.
Locating Addresses
• Place Names, Buildings (or Vanity
Addresses) are located by linking the nongraphic 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”
Geographic Base Files
An overview
Geographic Base Files
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Definition of the GBF
A Conceptual Overview
DIME File History and Structure
TIGER/Line Files Addressing Structure
Value Added TIGER
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.
Geographic Base Files
• May also be a referenced file containing
geographic coordinates to be used for nongeographic data.
• Typically these files attributes include:
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–
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street names / intersections
address ranges per street segment
census tract numbers
geographic coordinates
zip code centroids, political districts, etc.
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”.
Conceptual Use of a GBF
Non-Graphic
Data
Geocoding
Program
Geographic
Base Files
Non-Graphic
Data with
Geocodes
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.
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
Basic GBF File Structure
Heath Ave.
• What the Geographic Base File represents.
• An Abstraction of Reality (street networks)
34580
BLOCK #6
1198
P14
BLOCK #7
L20
1199
1100
1098
L22
1020
1101
1099
Gadberry Dr.
1021
P15
BLOCK #10
34581
P16
GBF Basic Concepts
BLOCK #6
GBF FILE (a Flat File)
1198
P14
1199
L20
BLOCK #7
1100 1098
1101 1099
P15
L22
Gadberry Dr.
1020
1021
P16
GBF FILE (Graphic Example)
The GBF contains “Ranges” of
potential addresses and “Lists” of
corresponding Street Segments.
Conceptual Geocoding Workflow
Non-Graphic
Data
Geocoding
Program
Geographic
Base Files
Non-Graphic
Data with
Geocodes
Non-graphic
Geocoding Workflow
Geocoding
Program
GBF Table
Geocoded
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.
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.
Geographic Elements used for
defining topological data structures
• Points - zero-dimensional objects on a map
which represent a single location on the earth.
• Examples:
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Street Intersections
Water Valves
Addresses
Fire Hydrants
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
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
General Topologic Relationship
Scheme
Points
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
Unique ID
Feature Type
Beginning Point
Ending Point
Unique ID
Feature Type
X coordinate
Y coordinate
Polygons
Unique ID
Feature Type
Boundary Lines
TIGER topology: Terms and
Descriptions
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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.”
TIGER topology (example)
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•
•
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Nodes
Entity Points
Complete Chains
Network Chains
• GT-Polygons
TIGER Line Files and Addresses
• The TIGER/Line ® files contain address ranges, not
individual addresses.
• The term address range refers 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.
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.
Basic characteristics of address ranges
• The TIGER/Line ® files generally contain only those citystyle 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.
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.
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.
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.
TIGER Address Range Example
Address Ranges and Impute Flag
Codes
Address Ranges
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•
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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)
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•
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Blank— No address range available
0— Not imputed
1— Imputed
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.
Multiple and Out-of-Sequence
Address Ranges
Address Range Special Cases
Imputed Address Ranges
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•
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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.
Address Range Imputes Before Split
Address Range Imputes After Split
Address Range Record
Locations
Record Type
1
1
1
1
6
6
6
6
9
Field Name
FRADDL
TOADDL
FRADDR
TOADDR
FRADDL
TOADDL
FRADDR
TOADDR
KGLADD
Description
Start Address, Left
End Address, Left
Start Address, Right
End Address, Right
Start Address, Left
End Address, Left
Start Address, Right
End Address, Right
Key Geographic Location Address
Impute Flag Record Locations
Record Type Field Name Description
1
1
1
1
6
6
6
6
FRIADDL
TOIADDL
FRIADDR
TOIADDR
FRIADDL
TOIADDL
FRIADDR
TOIADDR
Start Imputed Address Flag, Left
End Imputed Address Flag, Left
Start Imputed Address Flag, Right
End Imputed Address Flag, Right
Start Imputed Address Flag, Left
End Imputed Address Flag, Left
Start Imputed Address Flag, Right
End Imputed Address Flag, Right
Third Party Data Providers
• Geographic Data Technology (GDT)
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Dynamap 2000
Updated TIGER addresses and Street Centerlines
Don Cook has been doing this stuff since DIME
Census Bureau even buys their stuff!
• ETAK
– Very good product as well!
• DataMetrix, Inc.
Graphic Data Clean-Up Issues
Section IV
Graphic Data Clean-up
• Very Important if you plan to use existing
CAD or GIS data from another agency,
department, or private vendor as a base
map.
• Error Correction before you begin is key.
– Spatial errors (ie projection/coordinate systems)
– Topological (duplicate lines, gaps, dangles,
etc.)
Graphic Data Clean-up (cont.)
• Existing Attribute linkages on the graphics
can also cause “headaches”.
• Particularly if you plan to use graphics that
were attached to databases.
• Those “old” linkages can cling to the
graphic elements and cause troubles later.
• Potential errors are dependent upon which
GIS or 911 software is being implemented.
Line Weeding
• Line Weeding reduces the size and complexity of linear
data based on a user defined tolerance
• Line Weeding performs distance checks on linear data
• Benefits of weeding linework:
– Significant improvement in screen update times, plot-stroking
performance, and spatial analysis processing time
– Reduced disk space requirements
Cleaning CAD Linework
• The line cleaning tools correct errors in 2-D and 3-D linework.
• The line cleaning tools can:
–
–
–
–
correct undershoots or overshoots
break intersections
remove short segments
merge duplicate line segments
• The line cleaning tools can process:
– lines, line strings, arcs, curves, shapes, ellipses,
complex strings, and complex shapes
Common Line work checks
• Intersection Processing -- either break or flag intersections.
• Duplicate Line Processing -- merges duplicate line work
in 2-D and 3-D design files.
• Short Segment Processing -- removes zero-length lines and
short segments that have at least one free endpoint in 2-D
and 3-D line work.
• Endpoint Processing -- corrects or flags free endpoints, the
free endpoints can be either overshoots or undershoots.
Graphic Attributes also need to
be checked
• TIGER Address Ranges, for example, are
often incorrect (or blank) in Rural areas.
• Can be corrected and updated, but its
tedious work!
• Allow me to demonstrate, using a very
simple set of data and GIS software
package.
Attribute Edits
• Selected a street
segment with a
“NULL” value for
the address column.
Attribute Edits
• Edit the Attribute
Table to reflect
the address
ranges on the left
and right side of
the street.
• Geocode a
sample address.
Attribute Edits
• Confirm that the
street segment is
properly oriented
for placing the
“odd” address on
the correct side
of the street.
105 Gadberry Dr.
Attribute Edits
• Re-edit the
Attribute table.
• Reverse the
increase in value
in the left and
right address
columns.
Attribute Edits
• Geocode the
same address as
before.
• Resulting
geocode location
will be the
opposite end of
street segment.
Attribute Edits
• This is overly
simplified for the
purpose of this
demonstration,
but this is
basically how
you could go
about updating
the TIGER data
for a county.
Positional and Temporal
Accuracy in Address Databases
Our Primary Challenge !
Spatial Data Challenges
• Identifying Changes in our “service area”
before an emergency or service call...
• Positional Accuracy discrepancies between
data sources…
• Example: Comparing TIGER line data to
Digital Ortho-rectified Photography
Database Management Issues of
interest to Address Databases
Database Overview Agenda
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•
•
•
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Database Components
Example Data Types
Table Indexes
Domains
Joins and Views
Foreign and Primary Keys
Database Components
A database is the sum of all information you have obtained.
Database
Table 3
Table 1
col1
col2
col3
col4
Record/Row 1
Table 2
Table 3
Record/Row 2
Table 4
Record/Row3
Table 5
Record/Row4
Table 6
Table 7
Table 8
col5
Columns/
Fields
Sample Column Data Types
Character
Stores a maximum of 240 ASCII characters.
Integer
Stores an integer in a range -2,147,483,648 to 2,147,483,647
Smallint
Stores an integer value in the range -32,768 to 32,767
Double
Stores a real value in double precision floating point format
Real
Stores a real number value as a single precision floating
point
Decimal
Stores a fixed point decimal number with a optional
precision and scale
Timestamp
Stores a timestamp with ‘yyyy-mm-dd:hh:mm:ss’ format
Table Indexes
• A table index contains information from a specified
table and column
• The index allows you to sort information by column
and place this information in a table
• Indexes can be placed on columns that are frequently
used in queries and have few repeating values
• Indexes help to improve performance on queries
• A unique index can be created on a column that will
have unique values for each record
Domains and DB Integrity
• A domain allows you to check the validity of an entry into a
column in a database table against a corresponding set of
allowable values for that column
• Two types of domains exist
– Range domain -- used with numeric data and consists of
one or more inclusive minimum-maximum ranges
– List domain -- used with character data and consist of a
set of character strings
• Domains are stored in a series of domain tables
Relational Join
• A Join is a linkage between two tables in the database
• Columns from each table with like data types are used to
establish the join relationship
• There must be one identical value in the joined columns in each
table to complete the union
parcel_id
mslink
mapid
parcel_no
county_name
area_sqft
owner
parcel
parcel_id
assessed_value
zone_class
school_district
land_use
Database Views
• A view is a window that allows you to analyze
selected columns of joined tables.
• A view can be defined using either a single
join or multiple join relationships (ie using
several DB columns).
• Views are used for Query, Analysis and
reporting of Database Values.
• Makes huge DB Tables more user-friendly.
Primary Keys
Just Call them the “Record ID’s”
in a Database Table...
General Guidelines
• Should be numeric
• Must be Unique
• Do not change
• The shorter the better
• Automatically Generated
is best...
Column Names
*
Foreign Keys
Essentially the “Linkage Columns”
between Database Tables...
• Should/Must have a matching column in
another table with, at least some, matching
values.
• Require extensive planning during Database
Development Phase.
• Should be unique and numeric, but don’t
have to be….
What’s a Cartographic Feature
• Something from the real world represented in your
digital map: streets, streams, houses, trees, etc.
• A graphic element that contains a pointer to a record
in the Feature table
CAD Graphics Table
mslink
1
fname fcode ftype
road rd1
line
table
22
category fweight
3
2
flevel
fcolor
fstyle
29
0
0
Digital Map
digcmd
other...
Database Linkages on CAD
Graphics
“Old” DB Table ID
CAD File Graphics
record ID in “Old” Table
DMRS 8000 0004 0005 0000
DMRS 8000 0022 0014 0000
feature link
attribute link
The Database software will interpret the
“old linkage code” to determine what table the
graphic elements “points” to.
Relational Databases (example)
Feature Table
mslink
1
fname fcode ftype
road rd1
line
table
category fweight
22
3
flevel
fcolor
fstyle
29
0
0
2
digcmd
other...
Category Table
mslink
cname
3
trans
indexname indexlevel
CAD File Graphics
Maps Table
mslink
mapname
category
12
road1.dgn
3
roads Table
mslink
mapid
1
12
rd_name num_l
test
2
traffic
county
10100
morgan
MSCATALOG
Tablename
feature
roads
enitynum
4
22
nextocc
7
2
Joining Tables (DBMS)
Street Name Table
1:2
Sides Table
1: Many
Segment Table
Foreign Keys in each
table are used to complete
the Join Relationships from
Table to Table.
Joining Tables (example)
Segment Table in Graphics
Street Name Table
1:1
Segment Table
Master Address File
Address Database Design Issues
• Determine your “Audience” and their
needs.
• What’s your Geographic Extent?
• What Partnerships should be established?
• Establish Standards Early!
• Re-evaluate those Standards Regularly
Address Tables
• Parse the entire Address Record
– Always easier for “us average” DB users to
“merge” columns, rather than “split” them.
• Pay close attention to Primary Keys and
Foreign Keys during the Design and Testing
Phase.
• Conduct a Pilot Study for the entire
database structure before going “live”.
Address Tables (continued)
• Use Domains to control user input at
EVERY opportunity!
– List Domain (valid Street Names)
– Range Domains (valid numeric ranges)
• If gathering new addresses from more than
one source, collect them in “dummy” tables
before the DB “gatekeeper” cleans them up
and dumps them into the “master database”.
Address Data Entry
Specific data entry recommendations include:
1) Zip code entry first, with automatic fill of State and (optionally) locality
data.
2) Support on-line entry with help screens, pop-up valid values access,
and immediate edits.
3) Secondary unit data entry separate from street address (optionally
before street for emphasis).
4) Addresses entered with manual overrides of edits should be flagged for
future review.
5) Allow search for Zip code given City and State (optional).
Recommended Address Edits
Several types and levels of edits may be practical, depending on
circumstances and business purpose.
1) Check entered data for valid abbreviations. (Abbreviation standards
used by the USPS are included in Appendix B.)
2) Compare entered location(City) and State to Zipcode (based on GCS or
equivalent table information).
3) Check Zipcode for validity (based on GCS or equivalent table
information).
4) Compare entered address against valid addresses: Against an existing
database containing addresses (within the enterprise)
Recommended Address Edits
(continued)
5) Verify and correct the standard use of state code, standard spelling for
city; and presence of standard street type.
6) Inspect Street numbers that seem to represent ranges of addresses, such
as street numbers in a range or the use of terms such as "scattered
sites". (This only applies for those applications that receive addresses
representing, for example, blocks of apartments).
7) Identify and correct building name substitutions for street addresses to
the extent possible. Using COTS software modules, against a postalservice database of 140 million valid addresses.
8) If County Code is missing, generate County Code.
Recommended Address Edits
(continued)
9) Identify where range of latitude or longitude is more than 5 miles.
Inspect and correct.
(This is a way to measure if the geocoding center is of a Zip code,
rather than to a specific street address. This is unnecessary if the
geocoding level is specified in a code, as is recommended).
10) Identify and delete official verbiage. For example: "Township of",
"The Commonwealth of", "The Great State of".
11) Comma Check. The USPS recommends not using commas or other
dividers within addresses, except the hyphen in Zip+4. The USPS
further recommends all capital letters, to aid machine readability.
Recommended Address Edits
(continued)
12) Enforce Business Rules.
For example, it may be a rule that P.O. Box numbers (and equivalent)
may not substitute for Street names (and equivalent) if the address is
for a property in which the enterprise holds an interest (as opposed to
the mailing address of an individual or organization).
Database Loading Tools useful
for enhancing your GBF data.
• Bulk Update
– Attributes
• Area Loader
– Polygons
• Length Loader
– Lines
• Point Loader
– X, Y coords. from DB
• Label Loader
– from graphics to the
database!
Third-Party Database
“Scrubbers”
• Clean up un-parsed Address Databases.
• Remove duplicate records or misspellings.
• Can even Geocode database records for
you.
• Some provide CASS certified services for
Address clean-up.
Web Sites of Interest
• http://www.nonprofitmailers.org/vendors/page6old.htm
• http://www.census.gov/geo/www/tiger/vendors.html
• http://www.nena.org/ads/prodvend.htm
Rural Addressing Methods
Rural Addressing Methods
There are two primary means of means of
assigning locatable addresses:
• Distance Based Addressing: according to
the number of incremental units from the
beginning of a road.
• Grid Based Addressing: according to a predefined grid.
Rural Addressing
Distance-based Method
• Distance-based addressing establishes
house-numbering according to the number
of increments from the beginning of a road.
An increment can be any number of feet or
division of miles.
Rural Addressing
Distance-based Method (cont.)
• An increment can be any number of feet or division of
miles.
• Typical increments are 5-feet, 5.28-feet (.001 miles),
10-feet, 25-feet, 26.4-feet (.005 miles), 50-feet, 52.8feet (.01 miles) and 100-feet.
Rural Addressing
Distance-based Method (cont.)
• That is, by proceeding up a road, a new address is available at
each multiple of this increment.
• In addition, the parity (odd/even) of the address is established
according to the side of road.
• The side-of-road is relative to a vehicle proceeding along the
road in the direction of ascending numbers (from the beginning
of the named road odd numbers on the left and even numbers on
the right.
• Note: there are no USPS, NENA or other known national
standards for establishing parity.
Rural Addressing
Grid-based Method
• Grid addressing establishes a northing and easting coordinate
system for your municipality. Addresses are then developed
from the east-west coordinate (x) plus the north-south
coordinate (y).
• Numbers tend to be very large as each coordinate value is
generally 3-digits. If the municipality covers a large area, other
numbers may need to be added to indicate the sector of the grid.
In addition, any road that curves back in an east-west direction
can have addressing that is out of order (goes up and down).
This system may be suitable in flat areas where almost no
curved roads exist and the residents don't mind large numbers.
Rural Addressing Methods
• Official street numbers should proceed from a logical
point of origin and should be in proper numerical
sequence in relation to other lots with frontage on the
same street/road. It is recommended that a county
adopt a standard numbering sequence that goes from
East to West and South to North.
• Odd numbers are commonly assigned to the left side
of the street and even numbers to the right side of the
street.
Rural Addressing Methods
• Address numbers should be assigned to all structures
which are inhabited or which have or may have phone
service (including telephone booths) and not to lots
and parcels. Many lots have more than one structure
and thus require more than one address.
• Corner lots should be assigned a number according to
the frontage of the main entrance and/or where the
driveway meets the road - not where the mailbox is
located.
Rural Addressing Methods
• The logical/grammatical order of address elements
should follow USPS conventions: street number, predirectional, primary street name, suffix, postdirectional, and secondary number, if any (e.g., 100 W
Main ST SE Apt 201)
• Multi-unit structures should be given one primary
number (e.g., 101 Main ST or 103 Main ST) and
apartments or suites should be given numbers or
letters as secondary location indicators (e.g., 111 Main
ST, APT 101)
Rural Addressing Methods
• Primary street numbers should not be longer than six
characters
• There should be no fractional addresses (e.g., 101 1/2
Main ST)
• Alphanumeric primary or secondary address numbers
should not be used (e.g., EOI Main ST)
• Hyphenated primary or secondary address numbers
should not be used (e.g. 41-65 Bell ST)
Rural Addressing Methods
• Significant leading zeros in primary and secondary
numbers should not be used (e.g., 0145 Main ST)
• One letter road names should not be used (e.g., B
Street or Z Lane)
• Common practice is to number from east to west, and
from south to north
• Where one road starts and ends at points on a second
road (creating a loop), the numbering along the two
roads should be in the same direction
Adopting and Standardizing a
System for Addressing
• Municipalities planning an enhanced 9-1-1 project
should establish a single locatable addressing
system that is adopted for all addressing purposes
including emergency service provision, postal
delivery, municipal record keeping, and utility
service orders.
Address Increments
• NENA Standards recommend that communities adopt a 5.28'
increment. This increment would allow for 1,000 unique
numbered addresses per 1 mile length of road (there are 5,280
feet in a mile). This increment makes it very easy for an
emergency service provider in the event of an emergency to
look at the address and quickly figure out how far down the road
the house is located.
• For example, if an ambulance were dispatched to 500 Alpine
Lane (using a 5.28' address increment) the emergency vehicle
would know to travel exactly one half mile down Alpine Lane to
locate number 500.
Address Increments (cont.)
• Another benefit of the 5.28' increment is that structures can be
assigned an address every 10.5' on each side of the driveway.
• This means that many addressees are developed, mainly for
navigational purposes, but also for future development needs of
a community.
• If the appropriate measured numbering system is selected, a
community will never need to be re-addressed to accommodate
future development.
Local standards are a customization of the
nationally recommended methods
Addressing Standards that should be
considered on the local level
• Establish a 9-1-1 Committee to implement County-wide
Standards.
• Establish Road Naming and Re-naming Standards.
• Establish a Road Measuring and Numbering System that Fits
your county.
• Establish Addressing Standards that would require residents to
receive a new E-911 Address..
• Establish Road Signs and Address Number Standards.
• Consider Hiring a GIS/E911 Consultant.
Road Sign & Address
Numbering
• Naming roads and mapping them is among the first steps in an
addressing process.
• Placing road signs is one of the final tasks. To assist both
emergency service personnel and the general public, signs must
be visible and maintained.
• A frequent compliant about road signs is that they are often
hidden by tree branches. Annual trimming can eliminate this
problem.
Road Signs
• There are several varieties of signs that are suitable for public
road use. The most common is the green background with
reflective white lettering. However, regardless of color, the
important issue is to ensure the letters are tall enough to be
easily seen day or night.
• Sizes: Lettering on street name signs should be at least 4 inches
high, supplementary letting to indicate the type of street (e.g.,
Street, Avenue, Road, etc.) or section of city (e.g., N.W.) may be
in smaller lettering, at least 2 inches high.
• For rural areas: Municipalities should use 9 inch high blade in
lengths of 24, 30, 36, or 42 inches with 6 inch high letter for
street names, 4 inches for other.
Road Signs (cont.)
• For urban areas: Municipalities should use 9 inch high blade in
lengths of 24, 30, 36, or 42 inches with 4 inch high letter for
street names, inches for other.
• Placement: In business districts and on principal arteries, Street
Name signs should be placed at least on diagonally opposite
corners so that they will be on the far right hand side of the
intersection for traffic on the major street. They should be
mounted with their faces parallel to the streets they name. In
residential districts at least one Street Name sign should be
mounted at each intersection. In rural districts signs should be
placed to identify important roads not otherwise marked.
Basic Rural Addressing Tasks
• Determine the type of address numbering system(s) to
be used.
• Establish base maps for the entire area by using
existing data or developing you own centerline file.
• Determine ESN boundaries, telephone exchange
boundaries, city limits, and zip code boundaries.
• Research new developments, streets and sub-divisions
for centerline updates.
Basic Rural Addressing Tasks
(cont.)
• Determine property number ranges.
• Establish address standards and draft addressing
ordinances
• Build Master Street Address Guide (MSAG) and
supply to USPS, telephone companies and others.
• Determine a time-line for establishment and
adaptation of new address for rural structures.
Basic Rural Addressing Tasks
(cont.)
• Obtain citizens address and location records from all
possible sources.
• Locate every addressable structure from field
verification or aerial photography.
• Assign a property number to each structure or
driveway location on map.
Basic Rural Addressing Tasks
(cont.)
• Use citizen/location records and/or fieldwork to verify
name, telephone number and existing (old) address for
each structure.
• Match new property addresses with old address data to
create an Address Change File.
• Inform the USPS, telephone company, citizens and
others of the change of address and the date in which
the change will become official for mailing purposes.
Basic Rural Addressing Tasks
(cont.)
• Work with telephone companies and the USPS on
follow-up and error correction.
• Develop methods for address assignment by cities and
counties.
• Deliver indexed maps and atlases to cities and county.
• Establish a rigorous Data Maintenance schedule and
keep up with it by hiring qualified personnel.
Methods for locating Address
Changes
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•
•
Address Listings/Files - maintained by your government (including those
used for mass mailings or needed to provide essential services, such as police,
fire or sanitation programs) or purchased from commercial vendors are an
acceptable source for creating housing unit tallies for each census block,
provided they are current and comprehensive. You also can update
comprehensive address listings/files with additions and deletions from other
local records.
Tax Assessment Records - may supply up-to-date tallies of housing units.
Utility Connection Records - (electric, gas, water or sewer) are other sources
for developing housing unit tallies.
Other Methods for “Change
Detection”
Multiple sources:
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•
•
Property Permit Records
Certificates of Occupancy and Demolition Permits
Neighborhood visits
Special censuses
Aerial photography (DOQQ’s) and Current land use maps
Housing authorities records
Tribal, village, or Indian Health Service
Environmental Health Office records
When should Addresses be
Updated or Checked?
Local governments are in the best position to identify areas with potentially
missing or incorrectly assigned addresses.
For example:
• Has there been recent new construction activity in your community?
• Are there areas that have changed from single-family homes to multi-family
homes and vice versa?
• What about commercial or former public buildings that have been converted to
residential use?
• Are there new mobile home parks or even scattered new mobile homes?
• Do you have apartment buildings or boarding houses with irregular or missing
numbering schemes for the individual units?
• Are there blocks where you believe the Census Bureau missed housing units in
1990?
• Has your community recently annexed new territory, and thus new addresses?
Urban Addressing Issues
Urban Addressing Issues
• Most Common Address Systems in Urban
Areas:
– Base Line Method: References for an Addressing Grid
use paired perpendicular lines oriented North/South and
East/West.
– Quadrants: Four Zones of a city, quartered “roughly” by
a pair of perpendicular lines.
– Addressing Grid: Ranges for addresses are forced onto
the existing perpendicular street network
Urban Addressing Issues (cont.)
• Mostly dealing with new Street Naming and
Standardization.
• Continue to edit and update Address
Standards.
• Vacant Parcels will require an Address,
unlike the suggested Rural methods.
Common Urban Address Range
Methods
• Interval - Much like the distance method
used in the rural areas, where every so many
feet there’s a new number.
• Potential Range - Address numbers eligible
for assessment along a block (typically 100)
• Actual Range - Address numbers actually
assigned along a block (430-488) not (400498).
Urban Address Issues (cont.)
• Adjacent Municipal Jurisdictional conflicts.
– County verses the City? Who wins?
• Annexations and the expansion of existing
addressing grids.
• Development of an effective code for Street
Naming/Addressing conventions and
methods.
– Especially for contemporary sub-divisions
Urban Addressing Issues (cont.)
• Expansion of addressing into Rural Areas
with an existing 911 addressing scheme.
• Dealing with “prestige” or “vanity”
addresses.
• Issuing change of address notices.
• Keeping current updates among various
agencies.
• Cooperation is the key to success….
Addressing Standards and
Related Issues
Addressing Database Standards
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Kansas
Missouri
Michigan
Arkansas
Examples are provided on the CD-ROM