[mkgmap-dev] mkgmap:drawLevel and --order-by-decreasing-area

Tue Nov 15 10:45:44 GMT 2016

Here is a patch that implements mkgmap:drawLevel

It is used in conjunction with --order-by-decreasing-area and overrides
the natural polygon area that is used for output sorting, hence
influencing which polygons are rendered over others.

The higher the value, the later the polygon is written and hence should
show over other areas. Values range from 1 to 100, 1..50 will be larger
than any natural area and so output earlier. 51..100 will be smaller
and written later.

So, if you wanted the standard sea polygons to show, rather than any
mapped area beyond the coastline, could have:

natural=sea { add mkgmap:skipSizeFilter=true; set mkgmap:drawLevel=99 }
[0x32 resolution 10]

The default for sea is drawLevel=2 (drawLevel 1 might be needed for the
map background / 0x4b). Nothing else has a default and so behaves as if
between 50 and 51.

The Garmin device will still respect any in-build or TYP specified
_draworder. With --order-by-decreasing-area it works best if everything
has the same _draworder. If your Garmin device has strange rules, like
not showing City (0x01..0x03) or having green areas (0x14..0x21) at a
lower _draworder than most other things, consider a TYP file giving
0x01..0x55 the same value (1) except 0x4b with a lower value (0).

Ticker
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