[mkgmap-dev] Land polygon from sea generator

Mon Jun 6 19:06:26 BST 2011

On Mon, Jun 06, 2011 at 03:59:28PM +0100, Adrian wrote:
>I inspected the coastline data of this tile in JOSM and I could not see 
>any problem with it.

Did you invoke the JOSM Validator on it? The coastline checks are (or at 
least used to be) in the INFO level; you may have to crank up the 
chattiness.

Note that JOSM and mkgmap do not detect the same class of coastline 
errors; there is some overlap. Last time I had to use my brain a little 
was when mkgmap emitted a warning but JOSM Validator thought it is fine.  
If I remember correctly, the problem was that the map data contained two 
clockwise (or counter-clockwise) natural=coastline ways so that they did 
not intersect, but one way fully enclosed the other.

I would be surprised if mkgmap did not emit some coastline warnings for 
the map data. It is sometimes a bit challenging to decipher the messages 
and it might be impractical to keep the data tidy at all times. In 
Finland, coastline bugs occur rarely, maybe a few bugs once in a couple 
of weeks.

I only use extend-sea-sectors for one tile, as a work-around because the 
coastline in the finland.osm.pbf in the north (Tornio/Haparanda) does 
not extend to as far west as my tile would like to have it. Before going 
PBF, I had a sed or perl filter that moved the coastline endpoint to the 
west in the XML data.

Best regards,

	Marko