More ZIP Code FAQ - from carrierroutes.com
ZIP Code Mapping
How are boundaries for ZIP Codes defined?
The USPS does not define boundaries for ZIP Codes. Instead ZIP Codes represent clusters of addresses, grouped into these units for efficiency of delivery. In most cases ZIP Codes resemble spatial areas since they comprise spatially proximate street ranges. However, this is not always the case. In rural areas, ZIP codes can be collections of road lines (rural delivery routes) that in reality do not look much like a closed spatial area.
To map ZIP Codes with precise boundaries, as we often see them represented, the data provider essentially draws a line around all of the street segments encompassing addresses belonging to each code.
What is the difference between ZIP Code data provided by the USPS for free and that provided by a mapping service?
The USPS does not maintain or release ZIP Code maps; it only releases ZIP Code correspondence information in database format. Commercial vendors then take each ZIP Code’s information and attach it to a polygon that represents the dimensional area covered by that ZIP Code. Each polygon is then placed at the correct longitude and latitude within a map framework – thereby creating ZIP Code maps. The resulting ZIP Code map data is then integrated with other map software in a GIS system to be used in creating detailed multi-layered ZIP Code-related maps.
Are P. O. Boxes included in the mapping of ZIP Code boundaries?
P.O. Box ZIP Codes generally represent postal patrons from a diverse geography base (with some often being out of state or even country). These ZIP Codes are typically not included in ZIP Code mapping.
What is a ZIP Code centroid?
A ZIP Code’s centroid is a point near the center of the areas of a polygon for a 5-Digit ZIP Code. The centroid is calculated as the internal balance point, based on the coordinate extremes of the polygon. In cases where the polygon is irregular, the centroid may be adjusted so that ZIP Code labels never fall outside of the polygon.
Do carrier routes follow ZIP Codes?
Each carrier route is explicitly defined as part of a single ZIP Code. The full 9 digits of the carrier route code (e.g. 12508C007) is a unique code that defines each carrier route and so it cannot cross multiple ZIP Codes.
Why do companies use ZIP Code maps for direct mailing?
Companies eager to capitalize on the USPS discounts for bulk mailing by ZIP Code and carrier routes need ZIP Code maps in order to determine which ZIP Codes cover which neighborhoods. ZIP Codes have also been adopted by marketing people and by all kinds of other researchers as a standard geographic area, similar to a county or state. Therefore ZIP Code maps can be helpful for sales territory creation and management, and other custom applications.
Who provides ZIP Code maps? Can’t I get a ZIP Code map from the USPS?
The Postal Service does not maintain ZIP Code maps. Mapping ZIP Codes is challenging, especially because the delivery routes they represent are always changing. The USPS sends visitors to USPS.com looking for ZIP Code maps to Maponics and the Maponics Online Store.
How can I tell if a ZIP Code map is accurate and useful?
Because the delivery areas that ZIP Codes represent are constantly changing the primary concern in purchasing a ZIP Code map should be making sure that it has been updated at least within the past six months.
Are there areas of the nation that don’t have ZIP Codes?
Yes, in extremely rural areas where there is no mail delivery (deserts, mountains, lakes, most of Nevada) ZIP codes are not defined.
ZIP Code Mailing
What is a ZIP Code bulk mailing?
The term "bulk mail" refers to quantities of mail prepared for mailing at reduced postage rates. The post office offers reductions in postage for customers who are willing to share in the preparation work required to send a mailing. In order to conduct a bulk mailing, the mailer must be sending to more than 200 addresses within one ZIP Code.
Other requirements for mailing at bulk rates include:
Getting a mailing permit and paying an annual mailing fee
Paying postage using one of several methods: pre-canceled stamps, postage meter, or permit imprint
Ensuring that addresses are accurate
Presorting the mail pieces (separating or sorting by ZIP Codes)
Taking mail to the post office where the mailing permit is held
Your discount depends on the mailing service you choose and the work you do. For example, if you mail 1,000 letter-sized flyers to everyone in your ZIP Code, it would cost $0.41 per piece for retail First-Class postage, or $410. If you mail 1,000 flyers using Standard Mail to everyone in your ZIP Code by adding a barcode, sorting them by carrier route, and entering them for mailing at the appropriate sectional center facility, you might pay as little as $0.135 per piece, or $135. Letter shops and mail houses are experts in preparing mail for bulk mailings, and can be very helpful in figuring out how to save money.
Why does the USPS offer discounts for bulk mailings by ZIP Code?
Bulk mailing requires the customer to take on some of the labor typically executed by postal service employees (preparing, sorting and entering your mail). The post office rewards bulk mailers by sharing their labor savings through reduced postage rates.
Discount rates are not available for Express Mail or Priority Mail.
Are there ways to mail to just a portion of a ZIP Code and still get a saturation discount?
Yes. The steepest discounts offered by the USPS are for mailing by carrier route. Click here to learn more about mailing by carrier route.
Who normally mails by ZIP Code?
Business mailers whose target readers are usually concentrated in one small town or neighborhood are best served by mailing by ZIP Code.
Are demographics available by ZIP Code?
The U.S. Census Bureau collects demographic data and makes it widely available to the public. However it is released using Census geography measures such as block groups and census tracts, rather than postal geography. There are companies that are able to convert the data so it is viewable by ZIP Code and other postal geography, so that it can be used for marketing purposes.
How are boundaries for ZIP Codes defined?
The USPS does not define boundaries for ZIP Codes. Instead ZIP Codes represent clusters of addresses, grouped into these units for efficiency of delivery. In most cases ZIP Codes resemble spatial areas since they comprise spatially proximate street ranges. However, this is not always the case. In rural areas, ZIP codes can be collections of road lines (rural delivery routes) that in reality do not look much like a closed spatial area.
To map ZIP Codes with precise boundaries, as we often see them represented, the data provider essentially draws a line around all of the street segments encompassing addresses belonging to each code.
What is the difference between ZIP Code data provided by the USPS for free and that provided by a mapping service?
The USPS does not maintain or release ZIP Code maps; it only releases ZIP Code correspondence information in database format. Commercial vendors then take each ZIP Code’s information and attach it to a polygon that represents the dimensional area covered by that ZIP Code. Each polygon is then placed at the correct longitude and latitude within a map framework – thereby creating ZIP Code maps. The resulting ZIP Code map data is then integrated with other map software in a GIS system to be used in creating detailed multi-layered ZIP Code-related maps.
Are P. O. Boxes included in the mapping of ZIP Code boundaries?
P.O. Box ZIP Codes generally represent postal patrons from a diverse geography base (with some often being out of state or even country). These ZIP Codes are typically not included in ZIP Code mapping.
What is a ZIP Code centroid?
A ZIP Code’s centroid is a point near the center of the areas of a polygon for a 5-Digit ZIP Code. The centroid is calculated as the internal balance point, based on the coordinate extremes of the polygon. In cases where the polygon is irregular, the centroid may be adjusted so that ZIP Code labels never fall outside of the polygon.
Do carrier routes follow ZIP Codes?
Each carrier route is explicitly defined as part of a single ZIP Code. The full 9 digits of the carrier route code (e.g. 12508C007) is a unique code that defines each carrier route and so it cannot cross multiple ZIP Codes.
Why do companies use ZIP Code maps for direct mailing?
Companies eager to capitalize on the USPS discounts for bulk mailing by ZIP Code and carrier routes need ZIP Code maps in order to determine which ZIP Codes cover which neighborhoods. ZIP Codes have also been adopted by marketing people and by all kinds of other researchers as a standard geographic area, similar to a county or state. Therefore ZIP Code maps can be helpful for sales territory creation and management, and other custom applications.
Who provides ZIP Code maps? Can’t I get a ZIP Code map from the USPS?
The Postal Service does not maintain ZIP Code maps. Mapping ZIP Codes is challenging, especially because the delivery routes they represent are always changing. The USPS sends visitors to USPS.com looking for ZIP Code maps to Maponics and the Maponics Online Store.
How can I tell if a ZIP Code map is accurate and useful?
Because the delivery areas that ZIP Codes represent are constantly changing the primary concern in purchasing a ZIP Code map should be making sure that it has been updated at least within the past six months.
Are there areas of the nation that don’t have ZIP Codes?
Yes, in extremely rural areas where there is no mail delivery (deserts, mountains, lakes, most of Nevada) ZIP codes are not defined.
What is a ZIP Code bulk mailing?
The term "bulk mail" refers to quantities of mail prepared for mailing at reduced postage rates. The post office offers reductions in postage for customers who are willing to share in the preparation work required to send a mailing. In order to conduct a bulk mailing, the mailer must be sending to more than 200 addresses within one ZIP Code.
Other requirements for mailing at bulk rates include:
Getting a mailing permit and paying an annual mailing fee
Paying postage using one of several methods: pre-canceled stamps, postage meter, or permit imprint
Ensuring that addresses are accurate
Presorting the mail pieces (separating or sorting by ZIP Codes)
Taking mail to the post office where the mailing permit is held
Your discount depends on the mailing service you choose and the work you do. For example, if you mail 1,000 letter-sized flyers to everyone in your ZIP Code, it would cost $0.41 per piece for retail First-Class postage, or $410. If you mail 1,000 flyers using Standard Mail to everyone in your ZIP Code by adding a barcode, sorting them by carrier route, and entering them for mailing at the appropriate sectional center facility, you might pay as little as $0.135 per piece, or $135. Letter shops and mail houses are experts in preparing mail for bulk mailings, and can be very helpful in figuring out how to save money.
Why does the USPS offer discounts for bulk mailings by ZIP Code?
Bulk mailing requires the customer to take on some of the labor typically executed by postal service employees (preparing, sorting and entering your mail). The post office rewards bulk mailers by sharing their labor savings through reduced postage rates.
Discount rates are not available for Express Mail or Priority Mail.
Are there ways to mail to just a portion of a ZIP Code and still get a saturation discount?
Yes. The steepest discounts offered by the USPS are for mailing by carrier route. Click here to learn more about mailing by carrier route.
Who normally mails by ZIP Code?
Business mailers whose target readers are usually concentrated in one small town or neighborhood are best served by mailing by ZIP Code.
Are demographics available by ZIP Code?
The U.S. Census Bureau collects demographic data and makes it widely available to the public. However it is released using Census geography measures such as block groups and census tracts, rather than postal geography. There are companies that are able to convert the data so it is viewable by ZIP Code and other postal geography, so that it can be used for marketing purposes.