ZIP Code Tabulation Areas For Census 2000 - Population Studies ...
ZIP Code Tabulation Areas For Census 2000 - Population Studies ...
ZIP Code Tabulation Areas For Census 2000 - Population Studies ...
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<strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong><br />
<strong>For</strong> <strong>Census</strong> <strong>2000</strong><br />
NCHS, CDC<br />
Andrew Flora<br />
June 13, <strong>2000</strong><br />
TIGER Operations Branch<br />
Geography Division<br />
U S C E N S U S B U R E A U<br />
Helping You Make Informed Decisions<br />
TOB June 12, 1999
<strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong>s <strong>Areas</strong><br />
(ZCTAs)<br />
.... are generalized area representations<br />
of United States Postal Service <strong>ZIP</strong><br />
<strong>Code</strong>s developed by the U.S. <strong>Census</strong><br />
Bureau for tabulating statistical data.<br />
ZCTA is a trademark of the U.S. <strong>Census</strong> Bureau<br />
TOB June 12, 1999
1999 South Carolina <strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong><br />
<strong>Areas</strong> for select Dress Rehearsal Counties<br />
29715<br />
Select South Carolina Dress<br />
Rehearsal Counties<br />
29742<br />
29730<br />
29704<br />
29712<br />
29031<br />
29706<br />
29729<br />
29714<br />
297HH<br />
29055<br />
29720<br />
29058<br />
29067<br />
29718<br />
29175<br />
290HH<br />
29015<br />
29065<br />
29014<br />
29180<br />
29132<br />
29130<br />
291HH<br />
29074<br />
29075<br />
29016 29045<br />
29036<br />
29063<br />
29229<br />
29203<br />
290HH<br />
29223<br />
29212<br />
292<br />
29210<br />
29204<br />
29206<br />
29205<br />
29201 29209<br />
29061<br />
5 0 5 10 Miles<br />
290HH<br />
29020<br />
29078<br />
29128<br />
290<br />
29044<br />
29052<br />
29032<br />
29009<br />
29010
ZCTAs<br />
.... are distinct from other area<br />
representations of <strong>ZIP</strong> <strong>Code</strong>s because<br />
they reflect address locations and <strong>ZIP</strong><br />
<strong>Code</strong>s collected or verified during<br />
<strong>Census</strong> <strong>2000</strong> field operations.<br />
TOB June 12, 1999
ZCTAs<br />
.... are distinct from statistical areas such<br />
as census tracts because they are not<br />
stable over time and they are computer<br />
delineated using addresses rather than<br />
formally delineated before the census.<br />
TOB June 12, 1999
<strong>Census</strong> <strong>2000</strong> Dress Rehearsal <strong>Population</strong> Density<br />
Sacramento, CA Dress Rehearsal Site<br />
Comparison of Statistical Entities<br />
<strong>Census</strong> Tracts<br />
<strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong> (ZCTA)<br />
<strong>Population</strong> / square mile<br />
< 602<br />
602 - 1848<br />
1849 - 4386<br />
4387 - 6454<br />
> 6454<br />
Map Prepared by<br />
TIGER Operations Branch<br />
Geography Division<br />
U.S. Bureau of the <strong>Census</strong><br />
1999
Comparisons<br />
<strong>Census</strong> Tracts<br />
• Locally defined<br />
• Generally stable/comparable<br />
over time<br />
• Ideally 1500 housing units<br />
• Boundaries follow features<br />
• Nest within counties/county<br />
county equivalents<br />
ZCTAs<br />
• Defined by addresses and<br />
extension algorithms<br />
• Boundaries and codes change<br />
over time<br />
• Variable size<br />
• Boundaries follow tabulation<br />
block boundaries<br />
• Cross counties but not states<br />
TOB June 12, 1999
Introducing ZCTAs!<br />
• New for <strong>Census</strong> <strong>2000</strong><br />
• Product and trademark of the<br />
US <strong>Census</strong> Bureau<br />
• Prototype ZCTAs released with<br />
<strong>Census</strong> <strong>2000</strong> Dress Rehearsal products<br />
• Documentation is available on the web:<br />
http://www.census.gov/geo/ZCTA/zcta.html<br />
TOB June 12, 1999
Requirements for Building ZCTAs<br />
• Assign a ZCTA code to all land areas<br />
• Follow census block boundaries<br />
• Assign a single ZCTA code to each block<br />
• Use a fully automated process<br />
• Match true <strong>ZIP</strong> <strong>Code</strong>s as closely as<br />
possible<br />
TOB June 12, 1999
ZCTA <strong>Code</strong>s<br />
• Represent the majority <strong>ZIP</strong> <strong>Code</strong> of the<br />
addresses in a census block<br />
• Represent a USPS 5- or 3-digit <strong>ZIP</strong> <strong>Code</strong><br />
• Exclude unique, single delivery point<br />
<strong>ZIP</strong> <strong>Code</strong>s for firms and organizations<br />
• Include dedicated P.O. Box <strong>ZIP</strong> <strong>Code</strong>s<br />
In rural areas<br />
TOB June 12, 1999
ZCTA <strong>Code</strong>s<br />
• 5-digit numeric ZCTA codes<br />
22301 (land & internal water)<br />
• Generic 3-digit ZCTA codes<br />
223XX (land & internal water)<br />
223HH (water along margins of<br />
several land ZCTAs )<br />
TOB June 12, 1999
Challenges for Delineating ZCTAs<br />
• Addresses with incorrect or out-dated<br />
<strong>ZIP</strong> <strong>Code</strong>s<br />
• Blocks split between <strong>ZIP</strong> <strong>Code</strong>s<br />
• <strong>Areas</strong> with no addresses or <strong>ZIP</strong> <strong>Code</strong>s<br />
TOB June 12, 1999
<strong>ZIP</strong> <strong>Code</strong> Delivery Routes<br />
<strong>ZIP</strong> <strong>Code</strong>s follow the street network<br />
Addresses with <strong>ZIP</strong> <strong>Code</strong> A<br />
Addresses with <strong>ZIP</strong> <strong>Code</strong> B<br />
TOB June 12, 1999
ZCTAs Reflect Majority <strong>ZIP</strong><br />
Determine majority <strong>ZIP</strong> <strong>Code</strong> of available addresses<br />
ZCTA representing <strong>ZIP</strong> <strong>Code</strong> A<br />
ZCTA representing <strong>ZIP</strong> <strong>Code</strong> B<br />
TOB June 12, 1999
P.O. Box <strong>ZIP</strong> <strong>Code</strong>s<br />
Addresses with P.O. Box <strong>ZIP</strong> <strong>Code</strong>s scattered<br />
among addresses with city style delivery<br />
Addresses with <strong>ZIP</strong> <strong>Code</strong> A<br />
Addresses with P.O. Box <strong>ZIP</strong> <strong>Code</strong> B<br />
P<br />
TOB June 12, 1999
P.O. Box <strong>ZIP</strong> <strong>Code</strong>s<br />
P.O. Box <strong>ZIP</strong> <strong>Code</strong>s in areas with city style delivery<br />
are excluded from becoming ZCTAs.<br />
X<br />
ZCTA representing <strong>ZIP</strong> <strong>Code</strong> A<br />
P.O. Box <strong>ZIP</strong> <strong>Code</strong> B is excluded<br />
P<br />
TOB June 12, 1999
P.O. Box <strong>ZIP</strong> <strong>Code</strong>s<br />
Addresses with P.O. Box <strong>ZIP</strong> <strong>Code</strong>s clustered<br />
around post office in rural delivery areas<br />
Addresses with <strong>ZIP</strong> <strong>Code</strong> A<br />
Addresses with P.O. Box <strong>ZIP</strong> <strong>Code</strong> B<br />
P<br />
TOB June 12, 1999
P.O. Box ZCTA<br />
P.O. Box <strong>ZIP</strong> <strong>Code</strong>s in rural delivery areas<br />
may become ZCTAs<br />
ZCTA representing <strong>ZIP</strong> <strong>Code</strong> A<br />
ZCTA representing P.O. Box <strong>ZIP</strong> <strong>Code</strong> B<br />
P<br />
TOB June 12, 1999
Types of Unassigned Area<br />
Between<br />
<strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong> (ZCTAs)<br />
12346<br />
12345<br />
12345<br />
12345<br />
12345<br />
12347<br />
12347<br />
12346<br />
12346<br />
Internal Coverage Holes<br />
• waterway<br />
• park lands<br />
• industrial areas<br />
• undeveloped lands<br />
Coverage Gaps Between<br />
ZCTAs<br />
• waterway<br />
• park lands<br />
• industrial areas<br />
• undeveloped lands<br />
Fringe <strong>Areas</strong> and “Islands” Sparsely Settled <strong>Areas</strong><br />
Islands surrounded by coastal<br />
or inland waterways.<br />
Residential/commercial areas<br />
on the edge of:<br />
• farm land<br />
• public lands<br />
• large industrial or mining<br />
areas<br />
• undeveloped wetlands<br />
Sparsely located<br />
homesteads or small<br />
population centers in rural<br />
areas characterized by:<br />
• farming<br />
• ranch land<br />
• mining<br />
• forest land<br />
• wilderness areas
Internal Coverage Holes Within <strong>ZIP</strong> <strong>Code</strong><br />
<strong>Tabulation</strong> <strong>Areas</strong> (ZCTAs)<br />
12347<br />
• waterway<br />
• park lands<br />
• industrial areas<br />
• undeveloped lands
Internal Coverage Holes Within <strong>ZIP</strong> <strong>Code</strong><br />
<strong>Tabulation</strong> <strong>Areas</strong> (ZCTAs)<br />
12347<br />
Extend the surrounding ZCTA to fill “holes” within<br />
the coverage.
Coverage Gaps Between <strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong><br />
<strong>Areas</strong> (ZCTAs)<br />
12346<br />
12345<br />
12347<br />
• waterway<br />
• park lands<br />
• industrial areas<br />
• undeveloped lands
Coverage Gaps Between <strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong><br />
<strong>Areas</strong> (ZCTAs)<br />
12346<br />
12345<br />
12347<br />
123HH<br />
Grow ZCTAs outward to fill adjacent blocks until all<br />
gaps are filled.<br />
Assign special 3-digit water ZCTA codes to water<br />
features on the margins.
Unassigned Fringe <strong>Areas</strong> and “Islands”<br />
<strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong> (ZCTAs)<br />
12345<br />
12347<br />
12346<br />
Islands surrounded by coastal or inland waterways.<br />
Residential/commercial areas on the edge of:<br />
• farm land<br />
• public lands<br />
• large industrial or mining<br />
areas<br />
• undeveloped wetlands
Unassigned Fringe <strong>Areas</strong> and “Islands”<br />
<strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong> (ZCTAs)<br />
12345<br />
123XX<br />
12347<br />
123HH<br />
12346<br />
Fill unassigned blocks on the edge of ZCTAs with adjacent<br />
ZCTA code.<br />
Fill islands with the ZCTA code of nearby land areas.<br />
Assign a generic 3-digit ZCTA code to large unassigned land<br />
areas on the fringes of existing assigned areas.
Fragmented <strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong><br />
(ZCTAs) in Sparsely Settled <strong>Areas</strong><br />
123XX<br />
12345<br />
12346<br />
Dispersed homesteads or small population<br />
centers in rural areas characterized by:<br />
• farming<br />
• ranch land<br />
• mining<br />
• forest land<br />
• wilderness areas
Rural Fragments<br />
• Validate ZCTA <strong>Code</strong> in fragments<br />
• Add blocks along road network to<br />
bridge fragments<br />
• Respect natural and cultural boundaries<br />
• Fill in small enclaves and “cavities”<br />
• Leave remaining area as a generic ZCTA<br />
TOB June 12, 1999
Fragmented <strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong><br />
(ZCTAs) in Sparsely Settled <strong>Areas</strong><br />
123XX<br />
12345<br />
12346<br />
Assign ZCTA codes to “windows” that enclose the<br />
ZCTA fragments. The balance of the area<br />
receives a generic 3-digit ZCTA code.
Initial <strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong><br />
Sacramento, CA Dress Rehearsal Area<br />
95835<br />
95673<br />
95834<br />
95838<br />
95660<br />
95833<br />
95815<br />
95821 95841<br />
95814<br />
95816<br />
95819<br />
95825<br />
95864<br />
95818<br />
95817<br />
95820<br />
95826<br />
95822<br />
95824<br />
95831<br />
95823<br />
95828<br />
95829<br />
95832<br />
0 1 2<br />
3 Miles<br />
<strong>Areas</strong> with no MAF addresses appear in white.<br />
95758
<strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong><br />
Sacramento, CA Dress Rehearsal Area<br />
95835 95673<br />
95834<br />
95838<br />
95660<br />
95833<br />
95821<br />
95841<br />
95815<br />
958HH<br />
95814<br />
95816<br />
95819<br />
95825<br />
95864<br />
95818<br />
95817<br />
95820 95826<br />
95822<br />
95831<br />
95824<br />
95828<br />
95829<br />
95832<br />
95823<br />
0 1 2<br />
3 Miles<br />
95758
Initial <strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong><br />
Menominee, WI Dress Rehearsal Area<br />
54150<br />
0 3 6 Miles<br />
54135<br />
54174<br />
54124<br />
<strong>Areas</strong> with no MAF addresses appear in white.
<strong>ZIP</strong> <strong>Code</strong> <strong>Tabulation</strong> <strong>Areas</strong><br />
Menominee, WI Dress Rehearsal Area<br />
541<br />
54150<br />
54174<br />
54135<br />
0 3 6 Miles<br />
541HH 54124
ZCTA Maintenance<br />
• Monitor <strong>ZIP</strong> <strong>Code</strong> changes from USPS<br />
sources (<strong>ZIP</strong>MOVE file)<br />
• Monitor changes in summary statistics<br />
TOB June 12, 1999
ZCTA Summary Statistics<br />
• Create new MAF extract with<br />
- Latest <strong>ZIP</strong> <strong>Code</strong>s<br />
- New addresses<br />
• Match addresses and <strong>ZIP</strong> <strong>Code</strong>s to<br />
ZCTA assignments block by block<br />
• Identify negative changes in match rates<br />
TOB June 12, 1999
ZCTA Match Rates by Number of MAF Addresses<br />
South Carolina Dress Rehearsal Area<br />
100<br />
90<br />
80<br />
Percent of<br />
addresses where<br />
<strong>ZIP</strong> <strong>Code</strong> equals<br />
ZCTA<br />
70<br />
0 - 250<br />
250 -<br />
750<br />
750 -<br />
1500<br />
1500 -<br />
2500<br />
2500 -<br />
5000<br />
5000 -<br />
10000<br />
10000<br />
-<br />
15000<br />
Number of MAF Addresses per ZCTA<br />
15000<br />
-<br />
<strong>2000</strong>0
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