[mkgmap-dev] [Patch v3] LocationHook with new Quadtree

Sun Jan 15 08:45:33 GMT 2012

> Hi WanMil,
>
> If I see this right, we would see only a few changes if we split the ways on
> boundaries first. If you have an idea how to do it, please let me know (if
> you don't want to do it).

There are some detail problems left:
1. Up to now there is no clipper that splits lines at polygon borders. 
(or I haven't found it in the mkgmap source code?)
2. In case we have a closed way it is not clear to the LocationHook if 
it is a line or a shape. This is decided by the styles. A workaround 
would be to cut this way twice - one as line and second as shape. The 
line variant would be applied to the line style whereas the shape 
variant is only applied to the polygons style. This is not 100% correct 
(the polygon style would not apply if the line style has a hit) but it 
will solve most cases.
?? By the way: I never checked if it makes sense to add location 
information to shapes. Are they used gy garmin?

3. I expect that most streets do not end exactly at a city border but 
lots will end some meters after it. Cutting them will increase the 
number of objects much and we will have a lot of short streets. So maybe 
an overlapping threshold is required for the decision not to split a line.

> The remaining differences should be errors caused by the "insideness"
> problem of contains().

Problems with the bounding box of the quadtree should be solved by 
adding +1 to maxlat/maxlong of the java area object.

> I will be offline most of the weekend.
>

Have fun!
WanMil

> Ciao,
> Gerd
>
>
> WanMil wrote
>>
>> The tiles differ very much between r2168 and the patched version. So
>> there is some investigation work required to check if the patched
>> version does what it should do.
>>
>
>
>
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