[mkgmap-dev] Flooding in Southern Scotland

Sat Dec 31 20:17:11 GMT 2011

On Sat, Dec 31, 2011 at 05:37:43PM +0000, Roger Calvert wrote:
>Thank you both for your advice. The mkgmap log showed a very large 
>number of messages, but none at all relating to coastline.

There could have been some MultiPolygonRelation errors related to 
coastlines. I should mention that the checks in JOSM Validator and 
mkgmap are not overlapping that much. JOSM detects some things better, 
but it does not detect land-on-land or sea-on-sea situations as well as 
mkgmap, as it does not "colour" the areas.

>But using Bartosz's coastlines-europe file solved the problem (once I 
>had remembered to reference it before the data files), at the expense 
>of a rather larger gmapsupp file.

OK, in that case the issue might be that the Geofabrik cutting polygon 
is intersecting with some islets that have been added or moved fairly 
recently.

The Europe coastline at http://fabianowski.eu/osm/coastlines/ looks like 
it could be loaded into JOSM on a computer with enough RAM.

It could be an interesting exercise to ask Frederik Ramm for the cutting 
polygon in *.osm format and load it and the coastlines in JOSM, to see 
if the Geofabrik polygon can be improved. I did this for Finland a 
couple of years ago. In addition to the coastline, I observed the 
country border and a few lakes near the border when I edited the cutting 
polygon. It took a couple of iterations to get it fully right.

	Marko