[mkgmap-dev] Maintaining generated sea polygons

Tue May 25 12:34:36 BST 2010

On Thu, 2010-05-20 at 22:57 -0700, NopMap wrote:
> Hi!
> 
> I have been playing around with generated sea polygons. The algorithm works
> remarkably well - but I have been experiencing trouble due to inconsistent
> use of natural=coastline in the data.
> 
> There was an invalid use of natural=coastline in the planetfile, that caused
> a whole tile in the Alps to be flooded. So I tracked it down, fixed it and
> waited for the next planetfile. This time another tile near Berlin was
> flooded. I tracked it down, noted that another mapper had already fixed it
> and waited for the next planetfile. This time another tile south of Würzburg
> was flooded... - you note the pattern? :-)
> 
> For three weeks I have been unable to grab a planetfile with correct
> coastline for central europe - they are broken at about the same speed we
> can fix them. So even though I was able to build a really nice map a while
> ago, all update attempts were broken.
> 
> Therefore my question: Would it be possible to save the generated sea
> polygons to disk in osm format so an intact set of polygons can be re-used
> with future osm data? That way it could be ensured that future updates will
> have the same, correct sea polygons and not be randomly broken by temporary
> inconsistencies in the osm data.
> 
> Storing the image files and using them as a seperate map layer is not a
> solution as older Garmin devices are really cumbersome with layers or cannot
> handle multiple layers at all - and the map is for an older device.
> 
> Any ideas?
> 
> Nop

Hi,

I am not sure this question was answered completely, so I scrolled back
to the original post. I recall on reading the osmosis wiki that it can
merge OSM files.

osmosis --rx 1.osm --rx 2.osm --merge --wx merged.osm

Have you tried this?

Apologies if this was already understood.

Garvan