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Is it even possible to perform address (physical, not e-mail) validation? It seems like the sheer number of address formats, even in the US alone, would make this a fairly difficult task. On the other hand it seems like a task that would be necessary for several business requirements.
Here's a free and sort of "outside the box" way to do it. Not 100% perfect, but it should reject blatantly non-existent addresses.
Submit the entire address to Google's geocoding web service. This service attempts to return the exact coordinates of the location you feed it, i.e. latitude and longitude.
In my experience if the address is invalid you will get a result of 602 from the service. There's definitely a possibility of false positives or false negatives, but used in conjunction with other consistency checks it could be useful.
(Yahoo's geocoding web service, on the other hand, will return the coordinates of the center of the town if the town exists but the rest of the address is bogus. Potentially useful as long as you pay close attention to the "precision" field in the result).
There are a number of good answers in here but most of them make the assumption that the user wants an "API" solution where they must write code to connect to a 3rd-party service and/or screen scrape the USPS. This is all well and good, but should be factored into the business requirements and costs associated with the implementation and then weighed against the desired benefits.
Depending upon the business requirements and the way that the data is received into the system, a real-time address processing solution may be the best bet. If a real-time solution is required, you will want to consider the license agreement and technical limitations of the Google Maps/Bing/Yahoo APIs. They typically limit the number of calls you can make each day. The USPS web tools API is the same in additional they restrict how/why you can use their system and how you are allowed to use the data thereafter.
At the same time, there are a handful of great service providers that can easily process a static list of addresses. Essentially, you give the service provider a CSV file or Excel file, they clean it up and get it back to you. It's a one-time deal with no long-term commitment or obligation—usually.
Full disclosure: I'm the founder of SmartyStreets. We do address verification for addresses within the United States. We are easily able to CASS certify a list and we also offer a address verification web service API. We have no hidden fees, contracts, or anything. You use our service until you no longer need it and you can walk away. (Unlike cell phone companies that require a contract.)
USPS has an address cleaner online, which someone has screen scraped into a poor man's webservice. However, if you're doing this often enough, it'd be a better idea to apply for a USPS account and call their own webservice.
I will refer you to my blog post - A lesson in address storage, I go into some of the techniques and algorithms used in the process of address validation. My key thought is "Don't be lazy with address storage, it will cause you nothing but headaches in the future!"
Also, there is another StackOverflow question that asks this question entitled How should international geographic addresses be stored in a relational database.
In the course of developing an in-house address verification service at a German company I used to work for I've come across a number of ways to tackle this issue. I'll do my best to sum up my findings below:
Free, Open Source Software
Clearly, the first approach anyone would take is an open-source one (like openstreetmap.org), which is never a bad idea. But whether or not you can really put this to good and reliable use depends very much on how much you need to rely on the results.
Addresses are an incredibly variable thing. Verifying U.S. addresses is not an easy task, but bearable, but once you're going for Europe, especially the U.K. with their extensive Postal Code system, the open-source approach will simply lack data.
Web Services / APIs
Enterprise-Class Software
Money gets it done, obviously. But not every business or developer can spend ~$0.15 per address lookup (that's $150 for 1,000 API requests) - a very expensive business model the vast majority of address validation APIs have implemented.
What I ended up integrating: streetlayer API
Since I was not willing to take on the programmatic approach of verifying address data manually I finally came to the conclusion that I was in need of an API with a price tag that would not make my boss want to fire me and still deliver solid and reliable international verification results.
Long story short, I ended up integrating an API built by apilayer, called "streetlayer API". I was easily convinced by a simple JSON integration, surprisingly accurate validation results and their developer-friendly pricing. Also, 100 requests/month are entirely free.
Hope this helps!
I have used the services of http://www.melissadata.com Their "address object" works very well. Its pricey, yes. But when you consider costs of writing your own solutions, the cost of dirty data in your application, returned mailers - lost sales, and the like - the costs can be justified.
For us-based address data my company has used GeoStan. It has bindings for C and Java (and we created a Perl binding). Note that it is a commercial product and isn't cheap. It is quite fast though (~300 addresses per second) and offers features like CASS certification (USPS bulk mail discount), DPV (Delivery point verification) flagging, and LON/LAT geocoding.
There is a Perl module Geo::PostalAddress, but it uses heuristics and doesn't have the other features mentioned for GeoStan.
Edit: some have mentioned 'doing it yourself', if you do decide to do this, a good source of information to start with is the US Census Tiger Data Set, which contains a lot of information about the US including address information.
As seen on reddit:
$address = urlencode('1600 Pennsylvania Avenue, Washington, DC');
$json = json_decode(file_get_contents("http://where.yahooapis.com/geocode?q=$address&flags=J"));
print_r($json);
Fixaddress.com service is available that provides following services,
1) Address Validation.
2) Address Correction.
3) Address spell correcting.
4) Correct addresses phonetic mistakes.
Fixaddress.com uses USPS and Tiger data as reference data.
For more detail visit below link,
http://www.fixaddress.com/
One area where address lookups have to be performed reliably is for VOIP E911 services. I know companies reliably using the following services for this:
Bandwidth.com 9-1-1 Access API MSAG Address Validation
MSAG = Master Street Address Guide
https://www.bandwidth.com/9-1-1/
SmartyStreet US Street Address API
https://smartystreets.com/docs/cloud/us-street-api
There are companies that provide this service. Service bureaus that deal with mass mailing will scrub an entire mailing list to that it's in the proper format, which results in a discount on postage. The USPS sells databases of address information that can be used to develop custom solutions. They also have lists of approved vendors who provide this kind of software and service.
There are some (but not many) packages that have APIs for hooking address validation into your software.
However, you're right that its a pretty nasty problem.
http://www.usps.com/ncsc/ziplookup/vendorslicensees.htm
As mentioned there are many services out there, if you are looking to truly validate the entire address then I highly recommend going with a Web Service type service to ensure that changes can quickly be recognized by your application.
In addition to the services listed above, webservice.net has this US Address Validation service. http://www.webservicex.net/WCF/ServiceDetails.aspx?SID=24
We have had success with Perfect Address.
Their database has all the US street names and street number ranges. Also acts as a pretty decent parser for free-form address fields, if you are lucky enough to have that kind of data.
Validating it is a valid address is one thing.
But if you're trying to validate a given person lives at a given address, your only almost-guarantee would be a test mail to the address, and even that is not certain if the person is organised or knows somebody at that address.
Otherwise people could just specify an arbitrary random address which they know exists and it would mean nothing to you.
The best you can do for immediate results is request the user send a photographed / scanned copy of the head of their bank statement or some other proof-of-recent-residence, because at least then they have to work harder to forget it, and forging said things show up easily with a basic level of image forensic analysis.
There is no global solution. For any given country it is at best rather tricky.
In the UK, the PostOffice controlls postal addresses, and can provide (at a cost) address information for validation purposes.
Government agencies also keep an extensive list of addresses, and these are centrally collated in the NLPG (National Land and Property Gazetteer).
Actually validating against these lists is very difficult. Most people don't even know exactly how their address as it is held by the PostOffice. Some businesses don't even know what number they are on a particular street.
Your best bet is to approach a company that specialises in this kind of thing.
Yahoo has also a Placemaker API. It is good only for locations but it has an universal id for all world locations.
It look that there is no standard in ISO list.
You could also try SAP's Data Quality solutions which are available in both a server platform is processing a large number of requests or as an embeddable SDK if you wanted to run it in process with your application. We use it in our application and it's very robust and scalable.
NAICS.com is coming out with an API that will add all kinds of key business data including street address. This would happen on the fly as your site's forms are processed. https://www.naics.com/business-intelligence-api/
You can try Pitney Bowes “IdentifyAddress” Api available at - https://identify.pitneybowes.com/
The service analyses and compares the input addresses against the known address databases around the world to output a standardized detail. It corrects addresses, adds missing postal information and formats it using the format preferred by the applicable postal authority. I also uses additional address databases so it can provide enhanced detail, including address quality, type of address, transliteration (such as from Chinese Kanji to Latin characters) and whether an address is validated to the premise/house number, street, or city level of reference information.
You will find a lot of samples and sdk available on the site and i found it extremely easy to integrate.
For US addresses you can require a valid state, and verify that the zip is valid. You could even check that the zip code is in the right state, but beyond that I don't think there are many tests you could run that wouldn't provide a lot of false negatives.
What are you trying to do -- prevent simple mistakes or enforcing some kind of identity check?
Related
Is there any difference between HL7 USA and UK standards ? If its there then what are those ?
I'm not aware of any country-specific HL7 features neither did Google query site:hl7.org country specific reveal something eye striking. But it does not mean there are no differences
I guess your best bet would be to narrow your question down to a particular set of messages, register as member at hl7.org and ask this question through their internal mailing list (Even better best bet might be to talk to some friendly competitor and ask for the lessons learned)
In our country-specific HL7 community the membership is also paid, but the benefits of becoming a member are close to 0 from the developer's perspective. It's prestigious to be a member and it looks good on the business card. But all you get is access to downloadable specifications (but most of them are free for about a year anyway)
In the software I was working with we were exchanging only very small set of hl7 messages, namely: ADT^A04, ADT^A05, ADT^A08, ADT^A18, ADT^A23, ADT^A34, ORM^O01 and ACK in 2 different countries, considering adding 3rd country, without any country-specific features needed, except the convention used for identifying patient with his/her security number. The number format was country-specific but it was handled by upper software layers. The topmost customization was the number input mask and user input validation business rules at GUI level
What we did need, was an installation-specific or 3rd-party-system-specific message customization. For this customization you'll need rather the list of vendors of hardware and software your system will talk to. Once you have it, check their hl7 conformance statements
RFC 822, 3696 and others specify email address formats and how those should be validated by applications. Unfortunately in practice virtually nobody adheres to them, with most developers tending to invent a regex on the fly or copy-n-paste one from dubious sources to validate their user's email addresses. This in practice leads to many web services requiring email addresses, often as the primary identity of their users, yet only accepting a very limited subset of addresses that the RFCs actually allow.
So, can anything be said about the current state of what is generally considered a "web safe" email address? Is there some common subset that has crystalized over time that's accepted by most services? What's the standard for the HTML 5 email input type, which will hopefully eventually emerge as the default quick front-end validity check for emails?
Please note that I'm not asking what should be done to validate email addresses. Ideally validation should consist of light front-end validation which allows every possible address and possibly some false-positives, followed by a callback validation with the actual email server on the backend. I'm asking instead whether there is any sort of consensus on what the current implementations in the wild regard as valid. If I were to create a regex to validate email addresses (which I'm not, but humor me), what should that be to roughly match what everyone else does? If I were to create a new email address for myself on my own server, what safe subset should I stick to in order to be able to use that address at most web sites?
You pretty much answered your own question in your first paragraph.
TL;DR there is no consensus.
After searching the web and seeing that the PAF file is not free I'm guessing there is no way to do this.. but.. does anyone know of a free system that can find a list of address with a postcode. It just seems odd to me that google can show all address wherever you click on a map. It knows the bounds of a postcode area, but there seems to be no way of listing all those address.
I need a free solution. I'm aware of postcode anywhere and that their sales people are very active within stackoverflow, but I cannot afford to pay their prices on this project.
This project only requires UK and india postcodes.
If I understand correctly, you are looking for a list/database of all mailable addresses within a certain postcode? Is that right? That will be difficult to find, at least for free. I know you don't need US data, but for reference, the US Postal Service is not allowed to give out this type of information, even for a fee, due to privacy concerns. I assume that other countries have similar policies.
I work for a US-based address verification service called SmartyStreets so I have some experience with this. There are third party services, you mentioned one, that have aggregated their own lists from various sources and can generate "saturation" mailing lists for specific postal codes. However, due to the cost involved in generating and maintaining these lists, I doubt that you will find this type of list for free.
Systems have to sometimes accommodate the possibility of real world bad data. Consider that some data originates with paper forms. And forms inherently have a limited means of validating data.
Example 1: On one form users are expected to enter an integer distance (in miles) into a blank. We capture the information as written as a string since we don't always end up getting integer values.
Example 2: On another form we capture a code. That code should map to one of the codes in our system. However, sometimes the code written on the form is incorrect. We capture the code and allow it to exist with an invalid value until some future time of resolution. That is, we temporarily allow bad data since it's important to record the record even if some of it is invalid.
I'm interested in learning more about how systems accommodate bad data, that is, human error. Databases are supposed to be bastions of data integrity, but the real world is messy and people make mistakes. Systems must allow us to reflect those mistakes.
What are some ways systems you've developed accommodate human error? What practices have you used? What lessons have you learned?
Any further reading on the topic? (I had trouble Googling it.)
I agree with you, whatever we do there's no guarantee that we can get rid of bad or incorrect data. Especially, but not only, if it comes to user input. In my experience the same problems exist in complex integration projects, in which you have to integrate and merge (often inconsistent) data retrieved from different systems.
A good strategy is to decouple the input from the operational system itself. First, place user (or external system) provided data in a separate datastore (e.g. different schema). In a second step load this data into your operational datastore, but only if it confirms to strict rules (e.g. use address verification software to verify a given address). This Extract, Transform, Load (ETL) approach is fairly common in Data Warehousing (DWH) solutions, but can be applied programmatically in transactional systems as well (in my experience).
The above approach often leads to asynchronous processes in which the input is subitted first and (maybe) at a later time the external entity (user or system) retrives feedback whether its data was correct or not.
EDIT: For further readings I recommend to have a look at DWH concepts. Alhtough, you may not want to build such a thing, you could partially apply those concepts:
http://en.wikipedia.org/wiki/Extract,_transform,_load
http://en.wikipedia.org/wiki/Data_warehouse
http://en.wikipedia.org/wiki/Data_cleansing
A government department I worked in does a lot of surveys, most of which are (were) still paper based.
All the results were OCR'd into the system.
As part of the OCR process a digital scan of the forms is kept.
Data is then validated, data that is undecipherable or which fails validation is flagged.
When a human operator reviews the digital data they can modify the data if they are confident that they can correctly interpret what the code could not; they (here's the cool bit) can also bring up the scan of the paper based original, and use that to determine what the user was trying to say.
On a different thread; at some point you want to validate the data coming in against any expected data ranges that you want it to conform to; buy rejecting it at the point of entry you give the user a chance to correct it - the trade off is that every time you reject it you increase the chance of them abandoning the whole process.
At some point in your system you need to specify the rules which will be used for validation. At the end of the day a system is only going to be as smart as those rules. You can develop these yourself into the code (probably the business logic) or you might use a 3rd party component.
having flexible control over the validation is pretty important as they are likely to change overtime.
To be honest with you, one point of migrating from paper-based systems to IT is to remove these errors and make sure all data is always correct. I doubt any correctly planned and developed IT system (especially business financial systems) would allow such errors. Not in the company I am working for anyway...
There are lots of software tools that address the kinds of problems you mention. There are platforms and tools that let you define rules for scrubbing and transforming data and handling validation errors. Those techniques are widely used for Data Integration and Business Intelligence applications. Google for "Data Quality" or "Data Integration".
The easiest thing to do is to (this is not always possible) design the interface where users enter the data to limit as much as possible the amount of text that they need to enter. In my experience this seems to be where a lot of problems come from. One simple example of this is to provide a select, or auto-complete select field
One thing that you could do is do everything possible to determine if the data is correct before going into the db. I try to give the user entering the data as much feedback as possible so they can (ideally) fix some of the issues before the data gets persisted. For example, it is a very quick check to determine if the data being entered is of the correct type.
I got started in legal systems before the PC era. Litigation support databases routinely have to accommodate factually incorrect, incomplete, and contradictory information. It takes a different way of thinking.
The short version . . .
Instead of recording a single fact, you record multiple assertions about a fact. It boils down to designing a database to store data from assertions like these.
In an interview at 2011-01-03 08:13, Neil Rimes told Officer Cane
that he was at home from 2011-01-02 20:00 until 2011-01-03 08:13.
In an interview at 2011-01-03 08:25, Liza Nevers told Officer Cane
that Neil Rimes came home at 2011-01-02 23:45.
In a deposition at 2011-05-13 10:22, Cody Maxon told attorney Kurt
Schlagel that he saw Neil Rimes at Kroger at 2011-01-03 03:00
Creating a public poll.how do you validate that the user only vote once.I tried using an IP address but some organizations use 1 IP address.
It's no 100% solution, but you can use a browser fingerprint in combination with the IP adress. See this site for some usable and easily gettable browser properties.
Disadvantages: Some people may be left out (especially in large organizations with a very restrictive and thus homogeneous infrastructure), others may vote twice, for example by using different browsers.
If you want a 95% solution you have to require people to sign up with their email adress and proving that they received the email by klicking an embedded link, but depending on how much interest they take in voting, it may scare off a lot of potential voters.
A 100% solution for this problem does not exist, as far as I'm aware of.
Edit: Cookies are another obvious choice if you don't care too much about people gaming the poll system (just writing an auto-voter that ignores the cookies you send it).