[mkgmap-dev] Commit: r1410: Add --merge-lines option to combine lines at lower zoom levels.

Mon Nov 30 12:51:17 GMT 2009


Mark Burton wrote:
> Felix, Johann,
>
>   
>>> Okay, the merge-lines seems to be responsible for it! - However also 
>>> very aggressive dp filter settings might cause the tooltip to show up 
>>> slighltly away from the mouse (the tooltip will show up where the road 
>>> would be in resolution 24) - however only when using --merge-lines the 
>>> tooltip distance gets so great that sometimes it actually breaks using 
>>> the routing tool in Mapsource. Aggressive dp filter alone (=10) cause no 
>>> damage.
>>>
>>>       
>> Only to be sure I understand you correctly:
>> If you dont use the merge-lines option, then the error with the tooltip 
>> does not appear? If this is the case, then the fault lies for sure in 
>> the newly introduced merge line code.
>>     
>
> I can confirm that this issue exists. I think it's related to my
> posting the other day where I talked about the disparity between
> graphical lines and the routing arcs when the lines are being merged.
>
> My guess is...
>
> After merging you have 1 graphical line that spans the length of the
> combined lines associated with a routing arc that only spans the length
> of the original un-merged line. When you put the cursor near the lines
> that have been merged, mapsource, finds the arc associated with that
> line and puts the pop-up as close to the cursor as it can while still
> being on the arc. As the arc only spans a part of the whole merged
> line, the popup jumps (away from the cursor) to the end of the arc away.
>
> It's not really that surprising given the resulting data
> structure that has been produced by the merging.
>   
So if I understand correctly, the only real possibility for merging, 
will be before creating the routing?
And as I understood this is really complex (won't be implemented soon, 
because there are more important things to do). So for the while being 
the merge-lines can only be considered very experimental.

Also if we would have a non empty overview map for Mapsource (just like 
original Garmin Maps), We would only need resolution 18-24, if not only 
20-24 like Garmin City Navigator (on the GPS the basemap should be 
sufficient at lower resolutions) and therefore making a major rewrite 
here, might not even be that strongly needed. As in Mapsource very hard 
filtering brings no real speed improvements (a real overview map does 
however), it might be better to try to get a basemap with data instead.
> Cheers,
>
> Mark
> _______________________________________________
> mkgmap-dev mailing list
> mkgmap-dev at lists.mkgmap.org.uk
> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>   
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.mkgmap.org.uk/pipermail/mkgmap-dev/attachments/20091130/05df67f2/attachment.html