[mkgmap-dev] [PATCH] Option to extend sea sectors at extract borders

Mon Jan 18 00:49:50 GMT 2010

Felix,   

> Ups, just noticed that that once I zoom in to closer than 3km in Italy 
> everything is flooded (in Denmark there is no problem) as 0x10100 is not 
> set on resolution 24-20 (only 17-19) ( when using 
> --generate-sea=polygons,no-sea-sectors,extend-sea-sectors option and 
> then setting 0x4b to blue.
> 
> So the bug you discovered here (in WanMil's patch v3) cannot safely be 
> circumvented by using a clever TYPFile. On the other hand if I use 
> --generate-sea=no-sea-sectors,extend-sea-sectors then I miss most of the 
> sea in Italy (only Sicilly tile has sea).

I am guessing that the oversize sea sector is getting dropped somehow
by the clipping. Hopefully, WanMil will issue a new version that only
bloats the sea box when MP is being used.

> I'll try right now with only --generate-sea=extend-sea-sectors. Using 
> the =polygon switch it is clear that mkgmap does know 100% where there 
> is sea and where not. I simply don't understand why 0x10100 is not set 
> below 3km in Italy...
> >>
> >> I then tried it on Denmark (which previous to this patch posed problems)
> >> and it was working mint too.
> >>      
> > That's good.
> >
> > BTW, does mapsource for you draw lines at the tile boundaries which get
> > covered up by the land/sea polygons? I'm getting them now but I haven't
> > a clue where they are coming from.
> >    
> They are allways present. I just haven't got a clue why since a few 
> versions (can't really say which one), the are covered up by polygons. 
> Before and with "original" Garmin maps they are not covered up (at least 
> not when zoomed far out, they disappear once you zoom in).
> There are even Mapsource or Basecamp versions (I'm not sure current or 
> historic) where there is an option to switch them off. They are there to 
> help you pick the tiles you want to have (needed if maps have 0x4b set 
> in TYP-file because then you can't always see the tile being highlighted 
> if selected (to be sent to the GPS)).
> The color of these lines actually depends on 0x4b color.....

OK. Somehow, I have never really noticed those lines before (I live
in a dream world).

> > Also, I posted a little patch the other day that frigged the overview
> > map rounding so that it makes mapsource mouse popup balloons right up
> > to either side of the tile boundaries (without the patch, it only pops
> > up a balloon on one side of the boundary). Do you see that problem on
> > your maps?
> >    
> I cannot relate the above. Do you mean this patch:
> 
> /This patch stops the DP filter from discarding points at either end of
> a horizontal or vertical line segment (such segments are created by the
> clipper and also by the polygon splitter and, of course, could occur
> naturally in the OSM data but I'd guess they are relatively rare)./

No, it was called "fix overview bounding box rounding", but what I'm
asking is not whether you have tried that patch but do you see the
problem that the patch fixes? i.e. can you move the mouse across a tile
boundary and get a popup describing the map feature you are above. For
me, that popup would only happen on one side of the boundary, on the
other side, you had to move the mouse a quite a long way before it
started popping up words again. My belief is that the overview map's
rounding is wrong and so it doesn't match all of the tile's edges.

Mark