[mkgmap-dev] help needed for graphical problem

Thu Feb 12 18:29:07 GMT 2015

Hi Andrzej,

Yes, very long lines are no problem regarding optics,
but may cause trouble when the bresenham algo iterates
very often. Or do you see a simple way to limit the 
iteration to a part of the way near the wanted point?

My current algo tries to split the line when the address search for a house 
returns a point that is more than 40 m away from the closest possible point.
If that is not possible without visible distortion, it may also add an empty 
segment. 

Maybe 20m are also reasonable, but a much smaller value doesn't improve 
much while it will incease img size a lot. Maybe I add an option to 
configure the threshold values.

Anyway, it seems that there is no simple solution so I'll continue with what
I have.
A first usable version should be ready within the next days.
It will also support the typically random numbers from addr:place=* tags.

Gerd 

popej wrote
> Hi Gerd,
> 
> I have attached picture with 2 lines split around middle point. Upper 
> line is about 50m, lower 500m. Both have delta_lat equal to 1 grid step. 
> I don't think that splitting make big problem here.
> 
> If you allow for 10m of offset for splitting point, then Bresenham's 
> algorithm has to calculate only 8 points. For me it looks like a good 
> solution.
> 
> Are you going to insert multiple points into a line?
> 
> -- 
> Best regards,
> Andrzej
> 
> 
> _______________________________________________
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> mkgmap-dev at .org

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> 
> split.png (16K)
> &lt;http://gis.19327.n5.nabble.com/attachment/5833378/0/split.png&gt;

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