[mkgmap-dev] Bizarre flooding in South Wales

Mon Oct 10 11:44:07 BST 2011

Last week I generated a routable map for South Wales which does 
everything you'd expect concerning routing just fine, but suffers the 
well-known "flooding" problem.

Symptoms are a bit odd - it's not as if the flooding merely follows the 
coastline on the wrong side or anything. Just south and east of Swansea 
University for instance is a point where the sea seems to "turn inside 
out" and to the east (for a while) things are OK, but to the west the 
sea starts to grow outwards over the land.

At the "turn inside out" point, the sea to the east has contracted to a 
point, and to the west the sea spreads from that point (on the land). 
The point itself looks like two sea triangles touching at their shared 
apexes. (This is viewing it on a Garmin Streetpilot, no idea if it looks 
like that on MapSource or anything).

Another oddity is that on the west, the incorrectly spreading sea almost 
seems to be following a false coast slightly inshore of the real one for 
a short while. Then it floods everywhere.

I can put up the original .pbf files, tile .pbf files and the eventual 
.img file for this situation if anyone is interested.

Steve