In recent days a family in the Dutch town of Dronten became news as they shared how they have been the target of harrassment and threats for years, because the geo coordinates of their house happen to be near to the geographic midpoint of the country. People trying to trace the location of an IP address often get referred to that midpoint when there is no actual location known. This likely happens because services that provide location services for IP addresses use software that can’t handle unknown locations, so the midpoint of a country is entered as default. With detrimental consequences for whoever happens to live at that midpoint.

Years ago the Washington Post had a story of a house in Kansas that in a similar way was provided as the location for some 600 million IP addresses. The probability of someone being pissed of enough at someone running one of those IP addresses to send them a piece of their mind in the mail is 100%.

It also reminds me of an anecdotal story (I can’t find an online reference) I heard when shopping for a CRM system for my then employer some 20 years ago. CRM systems were gaining in uptake, and they of course have fields for zip codes. Many systems made adding zip codes to addresses mandatory, because of course if you want to send someone mail, you need the zip code. At the same time many contact records that get entered into these systems are incomplete, just a name with a phone number and company name etc. So what happens if the zip code is mandatory? Most people it turned out would type 9999 ZZ. That is a postcode allocated to Stitswerd, population 45, in the very north of the Netherlands where the nearest post office started receiving suspicious mountains of mail. The postcode 9999 ZZ isn’t actually used with an address (this Dutch article describes how the author went to have a look, with photos), it’s allocated to a road through the fields that has no houses. So in the end the Dutch mail sorting centers started sorting 9999 ZZ out, to prevent Sitswerd becoming the dumping ground of every unsollicited piece of direct mail in the country.

Lazy coding and design choices can wreak havoc.

3 reactions on “The Internet’s 9999 ZZ

  1. Reply All had an interesting episode on the topic:

    An interesting thing about Canadian Postal Codes is that they are technically not polygons, they are street address ranges.

    That said, they’re often used as if they are polygons, by finding the polygon that reflects the shape of the street address ranges, and the resulting polygon has a geographical centre that can then be mistaken, in a sense, for “where” the Postal Code is. If the street address range polygon ends of being oddly shaped, this calculated centre point can actually fall outside of the Postal Code.

    Canada lacks a national standard for neighborhood or district-sized geographical polygons, so these derived-from-Postal-Codes polygons are often used to stand in.

    • That Atlanta, Georgia example is even worse as it has people showing up looking for their phones and missing people even, with all the fresh emotion attached to that. Also interesting side mention of Sting Rays deliberately providing fake location info.

      Re zipcodes: Yes, always problematic such approximations. An early crime visualisation from the UK I saw, placed all the crime in the center of a zip code, which made it look like every crime from petty theft to abuse etc, all happened at number 12 Mainstreet or something like that.

  2. The mandatory field reminds me of an annoying problem which Moodle had (or still has? don’t know since I’m retired): The student’s city and country was required. For privacy reasons we recommended to use a fake code such as Christmas Islands. It was a pleasure to see how much phantasy the students had to play with these fields.

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