[mkgmap-dev] White stripes in the sea

Thu Jan 3 01:01:10 GMT 2013

WanMil wrote
> As a result we maybe have to break out an idea from the beginning of the 
> mp implementation. It would be possible to do the cutting at a later 
> position in the mkgmap chain. At the moment the cutting is done once for 
> all resolutions. It would be better to do the cutting separate for each 
> resolution. This would enable that in lower resolutions small inner 
> polygons could be removed from the mp cutting because the inner area is 
> so small that it is not displayed at that resolution.
> 
> That's an interesting idea and I guess it would improve the look of the 
> mkgmap generated maps quite a lot. At the same time I guess that it 
> doesn't make much sense trying to improve the mp cut algorithm because 
> you will reach similar problems again (one exception: the non 
> java.awt.geom.Area compatible algorithm might work because it does not 
> change the bounding box size of each polygon)

I agrree in all points. Do you have a concrete idea how we could change the
mkgmap chain? All the filter algorithms do only see type and sub-type values
and points,
but no information like sea or land.
I don't see an easy way to do the cutting of inner polygons with this
information.
If we read the TYP file we know the drawing order, maybe that is enough?

Would it be possible to define a TYP for a sea area that has many small
islands and then
automatically detect this for areas like the baltic sea? Else we have to
find an algo to decide
whether such a mixed area should be displayed as sea or land, esp. for the
low resulutions.

Gerd

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