[mkgmap-dev] is_in filter

Mon Feb 6 20:22:14 GMT 2017

I think it would be best to have this calculated the same as the bounds and
the sea. I guess in principle most map creators are interested in two facts:
really urban (huge cities), urban (small cities/suburbs - say max 500
inhabitants) and rural/countryside.
The biggest use case is highway=residential (is it on the countryside - or
in a built up area tiny city/suburb or city center)
also highway=tertiary, sometimes secondary is actually good for cycling in
really rural areas - in big cities much less (actually best to avoid big
cities alltogehter except on good quality cycleroutes)
highway=cycleway = often avoid in cities, but great on the countryside.

I imagine if this is precalculated - then the processing while creating the
map will be very quick, just like addresses for housenumbers - or am I
wrong?
Also this would allow more complex arguments for determining what is rural,
what is urban - and what is a huge city... 3-4 categories from urban to
rural should be enough for 99% of cases.

On 6 February 2017 at 20:55, Gerd Petermann <GPetermann_muenchen at hotmail.com
> wrote:

> Hi Carlos,
>
> okay, I thought about this for a while. We need quite a lot of new code
> for this, so I think
> the user interface should be as flexible as possible.
> If we want to support a style function like is_in(<exp>)
> where <exp> can be something like
> landuse=residential
> or more complex stuff like
> landuse=forest | natural=wood
> In short, I think it should support more or less all Tag_tests including
> regular expressions
> and combined expressions. A complete style rule could look like this:
> building=* & !is_in(landuse=residential | landuse=retail)   [0x13
> resolution 24]
> Those Tag_tests are used to filter the enclosing areas (closed ways,
> multipolygon-relations).
>
> I have no idea how to code the part that parses the style file.
> Is someone volunteering to code these changes?
> I think about a new class IsInFunction in package uk.me.parabola.mkgmap.
> osmstyle.function
> which would call an eval(element) method for each enclosing element. The
> eval method
> should return true / false.
>
> I'd like to code the needed methods to find the enclosing elements in an
> efficient way.
>
> If nobody finds a way to code the above style changes
> I can code a style function with a much simpler syntax like this:
> is_in_<key><val>()
> e.g.
> is_in_landuse_residential()
> or
> is_in_natural_wood()
> The name of the function gives the test:
> The enclosing element must have a key <key> with the value <val>
>
> Complex tests like regular expressions would not work with this.
>
> Gerd
>
>
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von
> Carlos Dávila <cdavilam at orangecorreo.es>
> Gesendet: Samstag, 4. Februar 2017 16:37:11
> An: Development list for mkgmap
> Betreff: Re: [mkgmap-dev] is_in filter
>
> Yes, I think that would work.
> I forgot to mention another use case. highway>residential which lies
> inside residential areas. They have typically maxspeed lower than
> outside residential areas, but are not correctly tagged in many cases.
> Proposed filter could be used to lower maxspeed for those ways.
>
> El 04/02/17 a las 16:18, Gerd Petermann escribió:
> > Hi Carlos,
> >
> > I see a performance problem if mkgmap has to evaluate that for each
> element.
> > I think it would be better to have a special tag like
> mkgmap:remove-if-in=<type>
> > which would tell mkgmap to find out if the object lies (completely)
> within a polygon
> > that has the given type. This can happen after processing all polygon
> elements.
> > The polygons with the given type(s) could be placed in a spatial index
> if performance impact
> > is too heavy.
> > Do you think that would work as well?
> >
> > Gerd
> >
> > ________________________________________
> > Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von
> Carlos Dávila <cdavilam at orangecorreo.es>
> > Gesendet: Samstag, 4. Februar 2017 16:06:20
> > An: Development list for mkgmap
> > Betreff: [mkgmap-dev] is_in filter
> >
> > One matter that has been discussed several times on this list is the
> > need to remove buildings. While removing buildings is becoming
> > absolutely necessary in many cities, due to massive building imports, it
> > may be quite convenient to keep them at rural or low densely populated
> > areas. Would it be possible to have a filter to know if a building is
> > inside/outside an area tagged landuse=residential, so that a different
> > rendering may be applied. Ideally area size could be also evaluated.
> > Perhaps some logic currently existing in mkgmap, used to assign
> > addresses from bounds, could be reused.
>
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-- 
Felix Hartman - Openmtbmap.org & VeloMap.org
Schusterbergweg 32/8
6020 Innsbruck
Austria - Österreich
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