[mkgmap-dev] Divide number in style file

Fri May 7 11:47:27 BST 2021

...|conv:"from=>to" does speed and weight conversions as well as length

This is the table (from mkgmap/osmstyle/eval/UnitConversions.java)

  static {
        Map<String, Double> m = LENGTH_FACTORS;
        m.put("m", 1.0);
        m.put("km", 1000.0);
        m.put("ft", 0.3048);
        m.put("feet", 0.3048);
        m.put("mi", 1_609.344);
        CONVERSIONS.put(UnitType.LENGTH, LENGTH_FACTORS);

        m = SPEED_FACTORS;
        m.put("kmh", 1.0);
        m.put("km/h", 1.0);
        m.put("kmph", 1.0);
        m.put("mph", 1.60934);
        m.put("knots", 1.852);
        CONVERSIONS.put(UnitType.SPEED, SPEED_FACTORS);

        m = WEIGHT_FACTORS;
        m.put("t", 1.0);
        m.put("kg", 0.001);
        m.put("lb", 0.00045359237);
        m.put("lbs", 0.00045359237);
        CONVERSIONS.put(UnitType.WEIGHT, WEIGHT_FACTORS);
    }

I see no reason why chaining conv| shouldn't work, but haven't tried
it.

Ticker

On Fri, 2021-05-07 at 17:56 +0800, Felix Hartmann wrote:
> yes I figured out the only current possible division would be to
> convert ft to mt - that could be run against population number as
> well of course.. Dividing the population number to get maps of India
> or China a bit less cluttered without using a specific style would be
> quite handy. Though yes - besides improving rules for cities not much
> else use of a division factor for values that I can think of. So
> right now only 3.28, 3.28^2, 3.28^3 and so on is possible (i did not
> actually check if it is possible to convert twice, but think so).
> 
> On Fri, 7 May 2021 at 16:56, Ticker Berkin <rwb-mkgmap at jagit.co.uk>
> wrote:
> > Hi Felix
> > 
> > I don't think there is any way to do maths on tag values.
> > 
> > It should not be too difficult to implement additional variable
> > filters
> > that do a simple maths op with a constant, eg:
> >   {set population='${population|divide:"7"}'}
> > 
> > Ticker
> > 
> > On Wed, 2021-05-05 at 22:58 +0800, Felix Hartmann wrote:
> > > Is it possible to divide a number by a factor in the style file?
> > > 
> > > ( mkgmap:country=CHN | mkmgap:countrz=CN | mkgmap:country=IND |
> > 
> >                                      ^^
> > > mkgmap:country=IN ) & ( place=city | place=island | place=town |
> > > place=village ) & population=* {set population='${population}/7'}
> > > 
> > > Did not work. I intend to divide the population in cities in
> > China
> > > and India because otherwise cities clutter up the map there (also
> > in
> > > India they do not use admin level ... which could be an
> > alternative).
> > > 
> > > -- 
> > > Felix Hartman - Openmtbmap.org & VeloMap.org
> > > 
> > > _______________________________________________
> > > mkgmap-dev mailing list
> > > mkgmap-dev at lists.mkgmap.org.uk
> > > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> > _______________________________________________
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> > 
> 
> -- 
> Felix Hartman - Openmtbmap.org & VeloMap.org
> 
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