[mkgmap-dev] Cutting down the default style

Mon Nov 7 20:05:31 GMT 2011

On Mon, Nov 07, 2011 at 01:20:06PM +0100, Felix Hartmann wrote:
>1. I think the default mkgmap style should be kinda universal and not 
>only for motorists. It shouldn't be specific and not show advanced 
>stuff that is only for certain user groups (routes, and so on).

Side note: My family is car-free. If anything, a leaner default style 
could be making the life of off-road users harder. But, they already 
need to combine contour lines separately.

>2. Multi layer maps are not a good solution. a) they work differently 
>depending on the gps unit (older Garmin GPS only allow only one 
>gmapsupp.IMG but inside you can disable/enable layers; newer Garmin 
>PNAs don't allow for this, but you can enable/disable maps only based 
>on name.IMG being separate).

Thank you for educating me. I did not know that newer units do not allow 
multiple layers within a gmapsupp.img.

>3. Therefore:
>basic stuff like building=*, power lines, and also most landuse/natural 
>keys should be in the default mkgmap style.

What if we extend the mkgmap style language with an 'import' or 
'include' directive familiar from other languages? There already is the 
base-style directive (used in resources/styles/marine/info), but it 
allows a style to import only one other style.

For polygons, the default style could 'import' or 'include' the 
following new styles:

water (sea and lake polygons)
natural (forests etc.)
landuse,building (land use by humans)
commercial (shop=*, amenity=*)

There could be some leaner styles distributed with mkgmap that would 
include only the 'water' and 'commercial' polygons.

Similarly, for lines, there could be multiple styles, all of which would 
be included by the default style:

motor (motorways, trunk roads etc. that are only for motor vehicles)
non_motor (footway, cycleway, path, track)
boundary
infrastructure (power=line etc.)

>4. Points file: I don't think the following are needed to be displayed 
>- the access rules could still apply - however for them to be more 
>effective they should be moved up front of the points file):
>barrier=bollard | barrier=bus_trap
>     {add access = no; add bicycle = yes; add foot = yes} [0x660f
>resolution 24]
>barrier=block | barrier=cycle_barrier | barrier=stile | barrier=kissing_gate
>     {add access = no; add foot = yes} [0x660f resolution 24]

I think that these are useful when collecting data for a map. Even 
though my area has good Bing coverage now, you cannot see all barriers 
in aerial images, especially if there are trees nearby.

>Also take into account the default style purpose 
>(resources/styles/info):
>The default style.  This is a heavyweight style that is
>designed for use when mapping and especially in lightly covered
>areas.

Right. The default style can stay, but I think that a leaner style could 
be useful in densely covered areas.

	Marko