Both terms refer to a group of linear mail delivery routes. What happens if you draw a shape around the lines and points? Environment. USPS ZIP codes correspond a set of roads, streets and specific addresses. Projecting Zip codes to a polygonal area will require you to make an educated guess where the boundary is between one zipcode and the next. Such “split routes” still contain all the necessary information to draw each polygon. Note: This file happens to include a polygon for the entire state of Massachusetts, which I don’t need. Third, note that at least one road segment highlighted in red (all having the same Zip code) occurs inside the purple zone where it is completely surrounded by all adjacent streets having a different Zip code. For the 2010 Census, ZCTAs should more accurately represent the actual ZIP Codes at the time of their delineation than they did for Census 2000. Although zip codes are not polygons, it seems like we should be able to come up with something better than the TIGER database which has only 33,144 of the 41,687 total zip codes in the US. In some cases, Zip codes have no physical location because they are assigned to a mobile or abstract "location" such as a military ship. Finding a specific postal extension location. US zipcodes are not actually polygons. Zip codes can be assigned to a single building or to a post office. Consider this problem. There are quite a few, thousands in fact, of Zip Codes that have no ZCTA. ZIP codes don't usually cross state lines, but some do (65733, 71749, and 73949 are good examples). That’s what ZIP Codes are designed for: delivery. It is totally possible to have service areas that would appear overlapping if they were delineated as contiguous polygons. Press question mark to learn the rest of the keyboard shortcuts. That answer and the others has resources for various GIS softwares: for example, ArcGIS. Its likely you will need to add more location data into your locations tables, possibly with Lat/Long coordinates to get something accurate. I told my old boss that their seven year old ZCTA/census tract intersection ratio idea was wrong, they were producing bad information, and that there are established better methods for estimating data from ZIP codes to other administrative geographies and she told me that their process has worked for long enough and saw no reason to change it. This is what commercial vendors of ZIP code boundaries do. ZCTAs are not to be confused with ZIP Codes, and they are not updated as frequently as ZIP Codes. This map is fairly typical of the situation in mid-sized urban areas. Purpose. They are NOT boundaries or polygons. For example it's entirely possible for a building with "LL59 5RR" as it's postcode to be next door to a building with "LL59 5SR". The process for delineating ZCTAs from the Census is different than say, NYC or DC’s process for delineating boundaries. ZIP code address data specifies only a center location for the ZIP code. I know this comment is all kinds of late, but this example is really helping me. Polygons recommended for optimal reverse geocoding results Our boundaries may overlap because the file was simplified to reduce size. Instead, they are a collection of postal routes, and so the boundaries are subject to change. The first digit of a USA ZIP code generally represents a group of U.S. states. With ZCTAs the GIS industry can now use a standard approximation that is the same used as the Census Bureau for publishing demographic information. I want my ZIP code polygons and address points to use the same one, so they line up properly. Known errors/qualifications: Metropolitan boundaries are delineated well. Time Period of Content. At work, we use the full ZIP+4 dataset from the USPS and can talk forever about this dataset. If you are interested in using Mappperz links, I would supplement his recommendations with a page that talks about what ZCTAs are and how they are created (Link). Second, note that there are many regions of overlap between the blue and the purple areas and between the purple and green areas (we should have used varying layer opacity so that the regions of overlap were clearer). USPS ZIP codes are not polygons but a set of lines and points typically not forming polygons. What amazes me is that this is how the USA operates. Let’s first go over the basic code needed to create one: Since I’ve personally found it more difficult to understand how to get all the components in place for a choropleth, let’s take a look at a separate visual to see how it works. Issue Even though Maps are selected on Show Me, ZIP codes of some countries are displayed as dots. I know this comment is all kinds of late, but this example is really helping me. In some special circumstances like a large city, or the aforementioned rural roads, a “fudged” zip code map could actually be wildly inaccurate. polygons. In a layer containing zip codes, we want to find all neighboring zip codes for every polygon. ZIP Codes are sets of points, not areas Area of the state of Arkansas (Licensed CC BY-SA 3.0) Regions like states, countries, and counties are defined by their borders and when represented as geographic data they are represented as polygons. And just to add further complication, there is absolutely nothing stopping a code sector and code unit appearing in an area surrounded by completely different sectors and units. Purpose. 96822-2323. (visualztion)I've looked everywhere but I can't seem to find any better. Boundaries have to be created using those address clusters and given latitude and longitude coordinates. ... when administrative boundaries such as ZIP Codes or voting districts, or mutually exclusive area classifications such as land form types cannot have any overlaps. Polygons can be disconnected, touch at a point, or touch along an edge. In a layer containing zip codes, we want to find all neighboring zip codes for every polygon. It was not intended to be an authoritative source on ZIP Codes. For example where I live is covered by SK postcodes for Stockport. Stockport is a part of an urban region called Greater Manchester - yet I do not live within the Greater Manchester boundary. Cause Tableau uses map data provided by our mapping partners: Map Data Partners.If polygons of ZIP codes of a country are not included in the map data, ZIP codes are displayed as dots. It’s totally possible to get data for insurance claims, go to map it, and a ZIP code doesn’t appear because the ZIP code was for a single building and not delineated into a polygon. Also, many communities for which the ZIP Code area is named are not incorporated, which means they do not have legal boundaries. ZIP code is the United States Postal Service's designation while postal code is used by other national post offices. USPS ZIP Codes are not areal features but a collection of mail delivery routes. The US Postal Service, of course, doesn't make it any easier to deal with such issues by making it easy to get Zip code information. In some cases, ZIP Codes may be associated with nonresidential P.O. county, counties. Environment. Here's a thread with zip code polygon sources and all the problems with zip codes as spatial boundaries. polygons. 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