[mkgmap-dev] Unit tests in trunk fail

Sun Jan 5 14:53:28 GMT 2014

Hi Gerd,

attached patch also contains fixes to the junit tests.
The performance is at least the same using the patch.

If you don't oppose the patch I want to commit it.

WanMil

> Hi Gerd,
>
> the SimpleTest also randomly fails because the number of resulting lines
> is sometimes different.
>
> You are right that the roadmerger does not change the number of lines in
> roundabouts. But there are other ways similar to roundabouts:
> http://www.openstreetmap.org/?mlat=51.25946&mlon=6.74760&zoom=17#map=19/51.25990/6.74788
>
> I guess such ways are responsible for different number of lines.
>
> Anyhow I have found a quite easy way to make the RoadMerger stable.
> When creating the list of roads I copy all start and end points to a
> list. This list is stable. Step by step I go through this list to find
> merge candidates. No matter if we allow to merge ways to a closed way
> this procedure is stable.
> Sorting at the end is still required because the roads are copied from
> the IdentityHashMap to the resulting list and this is not stable.
>
> Attached patch also contains the creation of a debugging file at the end
> of the RoadMerger.merge procedure. The output contains informations
> about the roads which makes it easy to compare two runs of mkgmap.
>
> Please give it a check if that solves your problem. I will have a look
> on the tests and if the performance is still acceptable using the patch.
>
> WanMil
>
>> Hi WanMil,
>>
>> it's a unit test regarding the style finalizer section which fails and I
>> don't know why.
>>
>> reg. RoadMerger:
>> it makes no sense to create closed ways because we would split them
>> again later in StyledConverter.
>> I don't understand the idea about roundabouts.
>> If one is divided into 4 parts you can do 2 merges without closing it,
>> no matter which
>> parts you connect first, and you should always get 2 remaining parts.
>> Assumes part a,b,c and d:
>> a+b and c+d or
>> a+b and a_b + c or
>> b+c and d+a  or
>> b+c and b_c + d or
>> b+c and a + b_c or
>> ...
>>
>> Gerd
>>
>>  > Date: Sun, 5 Jan 2014 12:37:09 +0100
>>  > From: wmgcnfg at web.de
>>  > To: mkgmap-dev at lists.mkgmap.org.uk
>>  > Subject: Re: [mkgmap-dev] Unit tests in trunk fail
>>  >
>>  > Hi Gerd,
>>  >
>>  > I think I found the problem:
>>  >
>>  > // check if merging would create a closed way - which should not
>>  > // be done (why? WanMil)
>>  > if (cStart == cOtherEnd) {
>>  > return false;
>>  > }
>>  >
>>  > The RoadMerger avoids to create closed roads. In case the roads are
>> not
>>  > merged in exactly the same order this is the reason for different
>> merge
>>  > results due to roundabouts. In case a roundabout is divided in
>> multiple
>>  > ways the number of merged ways is random.
>>  >
>>  > At the moment I have no time to check that more in detail but I think
>>  > the code listed above can be removed.
>>  >
>>  > WanMil
>>  >
>>  > > Hi WanMil,
>>  > >
>>  > > please have a look, I don't fully understand why.
>>  > >
>>  > > Gerd
>>  > >
>>  > >
>>  > > _______________________________________________
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>>  > > mkgmap-dev at lists.mkgmap.org.uk
>>  > > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>>  > >
>>  >
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>
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