The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

  • My badges

  • Twitter Updates

  • My Flickr Stream

  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 2,975 other subscribers

Last year, a classic Mojibake was introduced when Waterschap Amstel, Gooi en Vecht redesigned their IT systems

Posted by jpluimers on 2022/03/16

Last year, Waterschap Amstel, Gooi en Vecht sent me a paper letter notifying the yearly water bill was going to be late as they were redesigning their IT systems.

Their letter introduced a classic Mojibake that had not been present in all their older paper letter communication.

  • Street name on a letter via the old IT systems is "Pyreneeën":

    Pyreneeën goed geprint.

  • Street name on a letter via the new IT systems is "Pyreneeën":

    Pyreneeën geprint met Mojibake vervormingen.

It’s easily fixed by [Wayback/] ftfy · PyPI:

Python 3.9.5 (default, May 27 2021, 19:45:35) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import ftfy
>>> ftfy.fix_text("Pyreneeën")

Below is the English translation of the Dutch Twitter thread below the signature.

Reminder to self to check if this got fixed after I notified their web-care via


[] Jeroen Wiert Pluimers on Twitter: “Ik heb in 2019 al eens over de oorzaak een blog-post geschreven: een UTF-8 encoding van een karakter wordt 1 of meer keer vervormd door de UTF-8 bytes opnieuw als Unicode code-points te beschouwen en daarna nog een keer UTF-8 van te maken. 2/”


[Wayback/] Thread by @jpluimers on Thread Reader App – Thread Reader App

Luckily, @WoonVeilig isn’t alone. @waterschapagv is redesigning their IT systems. It means addresses are now handled wrongly in their paper correspondence: non-ASCII characters are mangled (techno-speak: #Mojibake)

Just look at the scans from letters in 2020 and 2021:

Pyreneeën goed geprint.
Pyreneeën geprint met Mojib...

Back in 2019, I wrote a blog post highlighting the cause of an almost identical failure: the UTF-8 encoding of a character gets malformed one or more times by re-treating the UTF-8 bytes Unicode code-points one or more times and then each round emitting them as UTF-8.

This example from the blog post matches: in exactly two rounds of mangling the lowercase letter e-diaeresis ë becomes a series of four characters: ë.

Hopefully I’ve given up on entering non-ASCII characters when entering data on-line helps @waterschapagv fixing this issue.

Involved unicode original characters (thanks to [Wayback] What Unicode character is this ?):

This might actually be related to [] Waternet int ineens 7 maanden aan drinkwaterkosten: ‘Echt belachelijk’ | Het Parool.




Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: