[mkgmap-dev] mapnik TYP, forest and wetland

Mon Nov 2 17:26:42 GMT 2020

Hi.
No worries. It just means that the map maker must be more thorough.
I can see that some makers take this into consideration, but others have not.
In effect it means that data is processed, but in the end cannot be shown if 
the TYP is applied at the end.

--order-by-decreasing-area, according to the documentation only works if the 
polygons have the same draw order, which these two do not by default.

Regards
Karl

On måndag 2 november 2020 kl. 18:18:11 CET Ticker Berkin wrote:
> Hi
> 
> I understand that many users prefer a fixed order of rendering based on
> the polygon type, and this is part of the definition of mapnik.txt and
> seems to be the 'Garmin' way of doing things.
> 
> If there is a consensus that the draworder should be different, then
> make it so. I'd think that wetland and forest should be the same as the
> other large-area landuse polygons, with priority 2
> 
> Option --order-by-decreasing-area removes the need to make any of these
> fixed rendering choices but at the cost of an increase in map size and,
> possibly, mkgmap execution time. It works for MapSource and BaseCamp
> and Garmin devices I've encountered, but not for GPSMapEdit.
> If used, it is best to set the draworder for all real polygons to the
> same value.
> 
> It is a shame that the TYP.txt file has to contain everything
> (draworder, translations and object colour/icons). It would be
> beneficial it they could separated and the wanted variants of
> components supplied to mkgmap.
> 
> Ticker
> 
> On Mon, 2020-11-02 at 16:55 +0100, 7770 wrote:
> > Hi.
> > 
> > In the example mapnik.txt TYP file, the draworder of the polygons for
> > woods/
> > forest 0x50 and wetland 0x51 are given like this:
> > 
> > [_drawOrder]
> > ..
> > Type=0x050,3
> > ..
> > Type=0x051,2
> > ..
> > [End]
> > 
> > 
> > When compiling a map, this means that wetlands in forests are not
> > visible if
> > this TYP is used.
> > 
> > I tried makling a map using the same draworder
> > Type=0x050,2
> > Type=0x051,2
> > plus using the option --order-by-decreasing-area
> > 
> > This makes the wetland visible in forests.
> > I could not see any negative impacts of this in the areas which i
> > checked (a
> > few in Sweden and Norway). Wetlands over other areas seems to work
> > fine as
> > well.
> > 
> > Do you think such a change would be of help or is there a great risk
> > that this
> > type of change would impact negatively on the drawing of the maps?
> > 
> > 
> > 
> > Regards
> > Karl
> > 
> > 
> > _______________________________________________
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> > mkgmap-dev at lists.mkgmap.org.uk
> > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> 
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