[mkgmap-dev] Squaring off of land outlines

Wed Feb 5 12:14:41 GMT 2020

Hi

A possibility would be to use Way.fullArea as the basis for the
filtering. This is calculated early in the OSM reading process and,
assuming the splitter keeps all points of a polygon that crosses a tile
boundary, it should have the same value for all the bits in all the
tiles. It is copied to MapShape.fullArea. If the polygon is split due
to clipping or multi-polygon processing, the same value is retained in
all the parts.

One possible problem with this is if mkgmap:drawLevel is set to a value
higher than 50 it forces the area to be set to a small value in the
range 1..50

Ticker

On Mon, 2020-02-03 at 22:44 -0700, Gerd Petermann wrote:
> Hi Mike,
> 
> Mike Baggaley wrote
> > Could a solution be to only discard the polygon if it is complete -
> > if it
> > is only a part of a polygon do not discard it. The
> > mkgmap:skipSizeFilter
> > tag should then be unneeded. This would also allow any very small
> > complete
> > sea polygons to be discarded.
> 
> Yes, good hint.
> If we keep the filter the routines which split a (multi-)polygon
> should set
> the skipSizefilter flag. I'll try now how different popular styles
> behave
> when the sizefilter is removed.
> 
> 
> 
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