[GraphHopper] There must be bug on the subnetwork removal

[John Zhao]

Hi Peter,

What I do is:
1. minOnewayNetworkSize = 20, minNetworkSize = 200
2. build san francisco bay area osm data
3. I print out the subnetworks result of the second call.

int remainingSubnetworks = preparation.findSubnetworks().size();

4. I found the subnetwork has some smaller than 200, like:

subnetwork start from: 37.32611992939085,-121.9961998312816 size: 24

subnetwork start from: 37.78373608999855,-122.25065187925067 size: 34


5. I can't understand why the subnetworks with 24 nodes and 34 nodes
are not removed by preparation.doWork();

It call the same method:

Map map = this.findSubnetworks();



*Best Regards,*
*ZhiQiang ZHAO*

On Mon, Jul 27, 2015 at 12:54 PM, Peter <graphhopper at gmx.de> wrote:

>  Hi John,
>
> sorry, I do not understand your problem or question here. Would you
> describe it again step by step for me :) ?
>
> Kind Regards,
> Peter
>
>
> On 27.07.2015 21:45, John Zhao wrote:
>
> Hi Peter,
>
>  Thanks.
> Actually I only have 1 flagEncoder in the EncodingManager.
> The call is exact same, preparation.findSubnetworks()
>
> preparation.findSubnetworks() using edgeFilter which is also from singleEncoder.
>
>
>  *Best Regards,*
> *ZhiQiang ZHAO*
>
> On Sun, Jul 26, 2015 at 7:56 AM, Peter <graphhopper at gmx.de> wrote:
>
>>  Hi John,
>>
>> it should not be related to calling these method twice. It is just one
>> time where you calculate the subnetworks independent of any FlagEncoder or
>> direction via findSubnetworks and the second pass is FlagEncoder- and
>> access-dependent via removeDeadEndUnvisitedNetworks.
>>
>> Regards,
>> Peter
>>
>>
>> On 24.07.2015 21:16, John Zhao wrote:
>>
>> Hi Peter,
>>
>>  I am still confused.
>> at first we call
>> map = findSubnetworks();
>>
>>  after the cleanup, we call the same method in Graphhopper.
>>
>> int remainingSubnetworks = preparation.findSubnetworks().size();
>>
>> Why the subnetwork was recognized the latter time, but not the first time?
>>
>> we remove some edges make it not connected?
>>
>>
>>  *Best Regards,*
>> *ZhiQiang ZHAO*
>>
>> On Thu, Jul 23, 2015 at 2:22 PM, Peter <graphhopper at gmx.de> wrote:
>>
>>>
>>>  Hi ZhiQiang,
>>>
>>> yes, according to the wiki this is wrongly mapped:
>>> * Avoid tagging highway intersections as that does not make clear which
>>> way has the impediment. *
>>>
>>> http://wiki.openstreetmap.org/wiki/Tag:barrier%3Dgate
>>>
>>> Peter
>>>
>>>
>>> On 23.07.2015 23:16, John Zhao wrote:
>>>
>>> Hi Peter,
>>>
>>>  Maybe the following one related with
>>> https://github.com/graphhopper/graphhopper/issues/388#issuecomment-88066385
>>>
>>>
>>>  I have a look at 37.32611992939085,-121.9961998312816.
>>> It seesm related with barrier=gate at intersection.
>>> http://www.openstreetmap.org/node/1126492194
>>>
>>>  *Best Regards,*
>>> *ZhiQiang ZHAO*
>>>
>>> On Thu, Jul 23, 2015 at 2:11 PM, Peter <graphhopper at gmx.de> wrote:
>>>
>>>>
>>>>  There are two types of subnetworks and the smaller ones seems to be
>>>> 'one-way subnetworks' which means they are eg. only reachable as
>>>> destination or start. But if you would start from a destination-only
>>>> subnetwork you'll get 'not found' for all points outside of this network.
>>>>
>>>> Regards,
>>>> Peter
>>>>
>>>>
>>>> On 23.07.2015 23:03, John Zhao wrote:
>>>>
>>>>  Interesting,
>>>> when I increase minOnewayNetworkSize from 20 to 50, the following two
>>>> disappeared.
>>>>  subnetwork start from: 37.32611992939085,-121.9961998312816 size: 24
>>>> subnetwork start from: 37.78373608999855,-122.25065187925067 size: 34
>>>>
>>>>  *Best Regards,*
>>>> *ZhiQiang ZHAO*
>>>>
>>>> On Thu, Jul 23, 2015 at 1:55 PM, John Zhao <johnthu at gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>>  I tried car flag encoder with following parameter on San Francisco
>>>>> bay area data from mapzen.
>>>>>
>>>>> https://s3.amazonaws.com/metro-extracts.mapzen.com/san-francisco-bay_california.osm.pbf
>>>>>
>>>>>  minNetworkSize=200
>>>>> minOnewayNetworkSize=20
>>>>>
>>>>>  I printed all the remaining subnetworks.
>>>>>  edges: 591932, nodes 437420, there were 3496 subnetworks. removed
>>>>> them => 13121 less nodes. Remaining subnetworks:5
>>>>> The remaining subnetworks are:
>>>>> subnetwork start from: 37.32611992939085,-121.9961998312816 size: 24
>>>>> subnetwork start from: 37.56018439442332,-122.30257814308803 size:
>>>>> 436637
>>>>> subnetwork start from: 37.78373608999855,-122.25065187925067 size: 34
>>>>> subnetwork start from: 38.180185962770565,-121.70631393878864 size: 301
>>>>> subnetwork start from: 37.85717050411933,-122.07633641532816 size: 424
>>>>>
>>>>>  I don't understand why there is still subnetwork less than 200 nodes.
>>>>>
>>>>>  I have a look at 37.32611992939085,-121.9961998312816.
>>>>> It seesm related with barrier=gate at intersection.
>>>>> http://www.openstreetmap.org/node/1126492194
>>>>>
>>>>>   *Best Regards,*
>>>>> *ZhiQiang ZHAO*
>>>>>
>>>>
>>>>
>>
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