[mkgmap-dev] Overview map for Africa

Mon Mar 25 13:50:18 GMT 2013

It means, resolutions below 18 are great, but in a separate overview 
map, not part of the normal *.img files.

Even better would be, if we could create the overview map in advance - 
maybe not even based on OSM material. There should be very simple 
overview maps - (first level - sea/land - maybe some major cities, only 
useful for continent maps, or country maps of Canada, Russia, China, and 
other huge countries, second level - add all capitals, add country 
borders, third level - add motorways, add cities with population >1 Mio 
(depending on the country). This could save processing time I imagine - 
by having the overview map, or at least the data used for it prebuilt, 
like the bounds and the sea files.

If we add a lower resolution to the main branch now, it should clearly 
only be an intermediary step to real overview maps. Overview maps are 
not transferred to Garmin GPS units, as they come with a preloaded world 
map, which offers decent performance when zooming out. If on the other 
hand we create maps with resolution 12 or 14, and no overview map, we 
make the GPS units painfully slow when zooming out and rely on the 
caching mechanism of Basecamp/Mapsource in order to get any kind of 
performance on the desktop (e.g. open a map of Asia, and grab a coffee 
until you can pan around well...).
On 25.03.2013 14:18, GerdP wrote:
> Hi Felix,
>
> I'm confused. You start with clear no, but the rest sound like a big yes ?
> Since I did not suggest any solution: What was the "no" for?
>
> Gerd
>
>
> Felix Hartmann-2 wrote
>> No, definitely not. There should rather be work on a real overview map.
>> There is a branch for it, but it lacks it's own style.
>> We will need a separate style for the overview map. This will greatly
>> help overview in Basecamp/Mapsource/Qlankdarte GT. On the device any map
>> lower than resolution 18, is bad, because the background map is much
>> better and 16 or 14 (speed!). If the map goes down to 14 or 16, than too
>> many tiles have to be opened, in order to draw it, hence a hefty
>> slowdown. Same on desktop. A multi-level overview map - say 12,14,16 is
>> what we really need.
>>
>>
>> There is a good description about overview maps also here:
>> www.*maptk*.dnsalias.com/*MapTk*/*MapTk*_en.pdf
>> -- scroll to page 20.
>>
>>
>> On 25.03.2013 09:31, GerdP wrote:
>>> Hi List,
>>>
>>> while testing the latest patches I found something strange:
>>> I created a map for Africa with default style using
>>> java -Xmx6000m -jar mkgmap.jar --max-jobs --nsis
>>> --precomp-sea=f:\osm\sea_20130308.zip
>>> -c template.args
>>>
>>> When I open this map in Basecamp I just see white rectangle. I have to
>>> zoom
>>> in multiple times to see
>>> anything. Wouldn't it be better to change the default so that we display
>>> at
>>> least the boundaries off continents on very low resolutions?
>>>
>>> Ciao,
>>> Gerd
>>>
>>>
>>>
>>>
>>> --
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>> -- 
>> keep on biking and discovering new trails
>>
>> Felix
>> openmtbmap.org & www.velomap.org
>>
>>
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>
>
>
>
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-- 
keep on biking and discovering new trails

Felix
openmtbmap.org & www.velomap.org