[mkgmap-dev] Sensible resolutions - (or patch 5)

Wed Mar 9 22:34:30 GMT 2011

Could this patch be included?

I really think maps in Western Europe (where most mkgmap users are) look 
much better on a) old GPS like etrex b) street units like Nuvi 255W or 
c) Mapsource/Basecamp/Qlandkarte GT.
About 2 month ago the resolutions for POI got lowered to sensible 
defaults (they were also way off, but on GPS this usually wouldn't get 
noticed as they simply did not shown them) - polygons and streets (very 
slight changes) should follow.

All answers below were about r. 1893 and Dutch problems with another 
commit but nothing to do with this patch.

On 02.03.2011 13:20, Felix Hartmann wrote:
> Even though the drop small polygons patch does improve mkgmap created 
> maps, there are still really bogus resolutions.
>
> take kindergarten polygon (or actually most amenity) which shows up 
> before! primary roads. Light rails (17) that in theory show up before 
> primary roads (only in theory because garmin does not display the 
> railway type before resolution 23, so cutting clutter, but still this 
> is a lot of crap and unused data that the default style puts into the 
> map). There loads of other examples.
>
> Certainly landuse like forest is more important on a map like a 
> kindergarten, grave_yard or college and so on.
> It really seams like, everyone just wanted to see his favourite stuff 
> really early, and by continuing this approach the maps get really 
> overloaded without providing any real information on top. Of course a 
> lot of this has been written when OSM had relatively few information, 
> and showing stuff stupidly early made the map look nice and gave the 
> impression of OSM having lots of data which it had not. Nowadays at 
> least in Western and Central Europe - and especially there where 
> people use mkgmap created maps, there is actually lots of information 
> in OSM and the goal has to be to declutter. That's what this patch 
> does. Adding so many polygons early in a raster map would be somehow 
> okay because it is barely noticeable, and there is no penaly in the 
> time to show it on screen, but on a vector map it is simply not good.
>
> On top of the resolutions changes I introduced resolutions 21 and 19 
> for rendering to have smoother addition of information when zooming. 
> Most of the data is in resolutions 24-22 anyhow (each resolution even 
> if showing the same detail, halves the space needed for including it). 
> Overall I think maps should work out the same size as without this 
> patch (even though there are two resolutions added), but draw much 
> faster on GPS/Mapsource/Qlandkarte GT and give a much better tool for 
> orientation. I don't think adding resolution=23 is good, because it 
> increases map size by more or less 25% (whereas 21 only increases 
> total map size by ~5%, 19 by ~1%)
>
> I still left most resolutions 1 step of where I would personally put 
> them, so that in countries with less information the style is still 
> working well. Nevertheless in big cities the map is showing much 
> information too early.