[GraphHopper] There must be bug on the subnetwork removal
Peter
graphhopper at gmx.de
Wed Jul 29 06:12:37 UTC 2015
Hi ZhiQiang,
hmmh, not sure if I understand what is unknown at your side.
Subnetworks are different things than oneway-subnetworks. For example
4-5 is a oneway subnetwork if connect with a oneway to the main graph only:
mainGraph->4-5
And this cannot be detected in step 2.
Please have a look at the unit tests to see more examples for the
different scenes
Regards,
Peter
On 28.07.2015 20:05, John Zhao wrote:
> Hi Peter,
>
> the result I posted is not the result of oneway-subnetwork procedure.
>
> The total procedures include:
> 1. remove zero-degree node
> 2. findSubnetwork
> 3. oneway-subnetwork procedure
> 4. findSubnetwork again on graphhopper.cleanup()
>
> My question is, why those islands are recognized on step 4, but not on
> step 2?
>
>
>
> *Best Regards,*
> *ZhiQiang ZHAO*
>
> On Tue, Jul 28, 2015 at 12:02 AM, Peter <graphhopper at gmx.de
> <mailto:graphhopper at gmx.de>> wrote:
>
> Hi ZhiQiang,
>
> I think it is because both networks are oneway subnetworks not
> found by the normal subnetwork procedure (but by the
> oneway-subnetwork procedure) and you defined the oneway minimum
> size to 20
>
> Regards,
> Peter
>
>
> On 28.07.2015 03:13, John Zhao wrote:
>> 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
>> <mailto: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
>>> <mailto: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 <mailto: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 <mailto: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
>>>>>> <mailto: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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