I’ve been having a great time recently using Osmium to write my own analysis code in C++ to look for anomalies in the PBF extracts. Today it found this very strange coastline in South Africa:

Perhaps, i thought, this is some rare geological formation, that makes an amazing wavy line? So let’s look at the data over aerial:

Uh…. what? I’ve seen a lot of weird and bad map data, like the mechanical grit of PGS and all the horrors of TIGER, but this was new. It’s as if some cartographer said… “yeah, it’s a coastline! Uh, what kind? Uh…. a wavy coastline? Yeah, wavy! Lots of waves…. I LOOOVE to draw WAVES, wheeeee!”

I should mention that this appears to go on for hundreds of kilometers.

The importer of this way is an “Adrian Frith” but it’s most certainly not his fault, the source tags says “Municipal Demarcation Board” so it was probably made by some government department, or maybe a contractor that was getting paid by the node?

I’m sorry to say I’ll be quickly tidying up this coast, so perhaps by the time you read this, you won’t be able to see the waves at, for example, here. On the other hand, coastline changes are special and take a while to process, so the blue ocean wobbles will probably stay for quite a while.