Standardizing MLS Addresses

Discussions around using and interfacing with the Church MLS program.
jfackerson
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Location: Longview, Washington, USA

#31

Post by jfackerson »

http://zip4.usps.com/zip4/welcome.jsp

Enter address.
To right of results, select on Mailing Industry Information.
View data across from field, Delivery Point Code.
For houses, this digraph is generated from last 2 digits of house address.
Below that will be field, Check Digit.
Check Digit is generated same way as last digit in Member Record Number.
Tack both onto end of 9 digit zip code.
There's no other residence in all US of A with that 12 digit zip code.

Seems to me that part of my Federal Tax money has already been
spent pairing street addresses with unique 12 digit zip codes, so why not just
buy or rent a copy of their existing data base and add Lat/Long,
in decimal degrees, of course. ESRI people have probably already done it for
some module within their ArcGIS application. We're already there. So why haven't we applied for it?
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aebrown
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Location: Draper, Utah

#32

Post by aebrown »

H. Forth wrote:http://zip4.usps.com/zip4/welcome.jsp

Enter address.
To right of results, select on Mailing Industry Information.
View data across from field, Delivery Point Code.
For houses, this digraph is generated from last 2 digits of house address.
Below that will be field, Check Digit.
Check Digit is generated same way as last digit in Member Record Number.
Tack both onto end of 9 digit zip code.
There's no other residence in all US of A with that 12 digit zip code.
It's really more accurate to call it an 11 digit code. The USPS (or a bulk mailer) adds a check digit to 5, 9, or 11 digit ZIP codes when they create the bar code. The check digit is very simply the digit required to make the sum of the digits (including the check digit) a multiple of 10. Software that creates bar codes will generally create the check digit for you, so I don't see much reason for storing it anywhere.

Also, although a check digit is added to a ZIP code, and the last digit of a Member Record Number is also a check digit, they are not generated in the same way -- they use quite different algorithms.

As for the Delivery Point Code, it won't really affect mailings that would be done in a ward or stake. But you said there was a different purpose: "In hopes of someday receiving access to a GIS keyed to existing unique 12 digit Zip Codes..." I'm not up on the GIS industry, but I would be surprised if GIS coding based on DPC were in the works, and my quick web search didn't reveal such an initiative. Is there some concrete reason for your hope? If not, it seems like the effort put into capturing DPCs would be better spent capturing lat/lon, which definitely will work with GIS systems.
RossEvans
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#33

Post by RossEvans »

H. Forth wrote:Seems to me that part of my Federal Tax money has already been
spent pairing street addresses with unique 12 digit zip codes, so why not just
buy or rent a copy of their existing data base and add Lat/Long,
in decimal degrees, of course. ESRI people have probably already done it for
some module within their ArcGIS application. We're already there. So why haven't we applied for it?

The missing link between the USPS file and GIS technology is actually geocoding the individual 11- or 12-digit records as points with lat/lon fields. To my knowldege, USPS has not done this, or if they have they do not make this database available even for a fee. You may know something I don't. BTW, the Postal service will quible with your argument about federal tax money, since the Postal Service is supposedly self-supporting. In any case, USPS is what it is and we can't change it.

Or are you saying that ESRI (a large GIS software company) has produced such a database that directly geocodes every postal address in the nation by this method? Of course, that would be a premium-priced product if it exists. Does it? ESRI could just be geocoding by other means, then applying that coordinate back to an 11- or 12-digit postal file. In which case the geocoding would not actually be determined by the USPS file at all.
jfackerson
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Location: Longview, Washington, USA

#34

Post by jfackerson »

During late 1990's I attended several ESRI sponsored classes using ArcView. There we were able to select on house locations and receive lat/long. Reverse would be possible too.

Actually USPS was with FedGov when Zip Coding first began in early 60's.
Too bad we can't access their data base in some way. Seems most of their work has already paired each residence with something unique, except for final step of pairing lat/longs.
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aebrown
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Location: Draper, Utah

#35

Post by aebrown »

H. Forth wrote:During late 1990's I attended several ESRI sponsored classes using ArcView. There we were able to select on house locations and receive lat/long. Reverse would be possible too.
I still am left wondering how the actual geocoding is done in the scenario you are describing. Is a lat/lon generated based on the street address, or based on the 11-digit ZIP code? If it's based on the street address, then any ZIP code beyond ZIP+4 seems pointless, since it wouldn't be used for mailings or geocoding. If it's based on the 11-digit ZIP code, then I'd be really interested in knowing what software/database/service makes that connection between the ZIP code and the lat/lon.
jfackerson
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#36

Post by jfackerson »

I've messaged a few of our forum comments over to a ward associate at USGS. Maybe he'll eventually join us or e-mail me back. He has a GIS degree from BYU.

Years past, I've seen people walking around our neighborhood wearing backpacks having a long protruding antenna topped with a flat sauser type thingy. They were aiming laser pistors at telephone poles to re-map our local power grid. Doing such a thing for each residence would be very easy. Accuracy, I've been told, is within range of +/- 6 centimeters for lat/longs expressed in decimal degrees. I'd conclude that it's probably already been done. Now, who'd have such data? 911 response people use such data all the time to direct their rescue personnel and vehicles.
russellhltn
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#37

Post by russellhltn »

H. Forth wrote:Years past, I've seen people walking around our neighborhood wearing backpacks having a long protruding antenna topped with a flat sauser type thingy.
During an office visit to a board of water supply I saw similar equipment. My contact said it was to used to map the location of water meters.

All this accuracy raises another question - what point would people be mapping? Clearly the water department wants to know where their buried meters are. The Post Office wants to know the location of the mailbox. The location we use for our chapels affects the directions given.
RossEvans
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#38

Post by RossEvans »

H. Forth wrote:During late 1990's I attended several ESRI sponsored classes using ArcView. There we were able to select on house locations and receive lat/long. Reverse would be possible too.

Although marketers at ESRI would be happy for us all to believe that the company is so omniscient that it has affirmatively pre-geocoded every home in the country from secret USPS files, I do not believe this is so.

What you saw at ESRI's classes was probably conventional street-address geocoding, which parses street addresses and assigns lat/lon coordinates by a variety of methods. Typically these methods involve segmenting streets into address ranges and interpolating. Some high-end vendors augment this with county tax-parcel data and other files to get more accurate estimates of lat/lon coordinates. There are several vendors who provide such services or produce the basemap data used by geocoding engines. ESRI, whose primary business is developing and marketing high-end and expensive GIS software, is either an original producer or reseller of such products. I am quite sure their software product line includes a geocoding engine.

However, reserving the right to be mistaken, I'm pretty sure that if ESRI had a product based on the USPS database in which USPS had assigned the geographical coordinates, I would have bumped into this in my travels. I have not.

As for the government and street-address geocoding, most of the action has been at the Census Bureau, which was a pioneer in this field. The Census TIGER files, first produced about 20 years ago and incrementally improved since then, have formed the foundation of street-address geocoding in the United States. The TIGER files are now available for free and useful within limits, but are considered flawed for a variety of reasons. (The biggest reason being that while Census in its pioneer TIGER project got the topography of streets, creeks, etc, pretty complete, their positiional accuracy was fair at best. In other words, many streets are mapped in the wrong place. Census is working to correct these flaws, and eventually there will be better public-domain basemap files available.) Meanwhile, the commercial GIS map producers add value in part by correcting and augmenting what Census has done. These producers also work directly with local governments to acquire updated map data. They may even commission their own aerial surveys.

No geocoding of which I am aware is 100 percent complete or accurate. To accomplish good geocoding one must have robust geocoding software and good GIS base maps for that software to read. Geocoding can also be accomplished through companies that provide services over the Internet or by batch processing. End-users typically see this in action when addresses are geocoded and mapped on-the-fly by Google, Yahoo, Microsoft, MapQuest, etc., all of whom are using some form of licensed basemaps produced by a handful of private-sector suppliers such as TeleAtlas or NAVTEQ. The result is an interaction between the web services' own code and software they license.

None of that comes from the Postal Service. But getting our addresses validated and standardized to USPS standards now would have several purposes: It gets the mail delivered more accurately and efficiently, IT assistS our own home-teachers and other members in the process, and it is the first step in transforming each address so that it can be fed more reliably into a geocoding engine.
RossEvans
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#39

Post by RossEvans »

H. Forth wrote:http://zip4.usps.com/zip4/welcome.jsp

Enter address.
To right of results, select on Mailing Industry Information. ...

As an aside, if you are going through all the labor of doing this one-at-a-time from the USPS web page, you might consider capturing the Carrier Route code instead. This four-character string potentially has greater utility to a ward. It might be worth keying this code into the legacy "Geo Code" fields in MLS, if they are not populated by any other scheme.

The reason is that this code is assigned by the Postal Service to subdivide Zip Codes into subsets that actually make sense on the ground for someone physically traversing the area. That is, your local mailman.

Thus, these codes are potential candidates for purposes ranging from ward boundary alignments to managing fast-offering districts. If the Carrier Route codes were captured in the legacy MLS fields, then it could support such purposes directly, without everyone owning GIS software.

Of course, to take advantage of that you would need boundary files that subdivide the ward map geographically by Carrier Route. Believe it or not, USPS does not produce Carrier Route GIS files either, but some private-sector vendors buy the USPS database and reverse-engineer the Carrier Routes into two-dimensional GIS polygons that can be plotted on a map. The trick is obtaining such files at an affordable cost; typically the price of such products is off the scale for a ward budget.

p.s. For the work you are doing, you probably could geocode lat/lon coordinates manually for each address in the ward, using a variety of free online sources.
jbh001
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Location: Las Vegas, NV

#40

Post by jbh001 »

boomerbubba wrote:As an aside, if you are going through all the labor of doing this one-at-a-time from the USPS web page, you might consider capturing the Carrier Route code instead.
I did exactly that (or a variation of it) in my current unit. Since our unit covers several ZIP codes, I devised a "Ward Geo Code" comprised of the ZIP code and most of the carrier route. This resulted in a nice way of grouping address together. The only downside was that the Ward Geo Code field was one character short of being able to hold a 5-digit ZIP code and a 4-digit carrier route code.
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