[pgrouting-dev] Support for Time Constraints

Jay Mahadeokar jai.mahadeokar at gmail.com
Tue Jun 14 21:56:57 EDT 2011


On Sun, Jun 12, 2011 at 8:00 PM, Stephen Woodbridge <woodbri at swoodbridge.com
> wrote:

> Jay,
>
> Try:
>
> select class_id, count(*) as cnt from ways group by class_id oder by
> classid;
>
> Typically you should a a distribution in real world data something like:
>
> 5% limited access major highways
> 15% major roads
> 75% minor roads
> 5% trails, pedestrian ways, etc
>
>
Hi,

We have got following data in the pgrouting-workshop ways table.

pgrouting-workshop=# select distinct(count(class_id)) as
no_of_entries,class_id from ways group by class_id order by no_of_entries;
 no_of_entries | class_id
---------------+----------
             2 |      111
            11 |      117
            17 |      102
            21 |      101
            43 |      100
            45 |      122
            90 |      112
           109 |      401
           221 |      108
           234 |      106
           248 |      109
           252 |      119
          1259 |      114
          2761 |      110
(14 rows)


The classes table in routing database gives more information on the class_id
field.  Also available here:
http://workshop.pgrouting.org/chapters/advanced.html

So, we have:

class_id    name                no_of_entries

110           track               2761
114           path                1259
119           steps               252
109           service            248
106           primary            234
108           living_street     221
401           roundabout      109

These are the major class_types with more than 100 entries in ways table.

Steve had earlier suggested following idea for time dependent data
generation:

"If we think about "rush hour" around a major city, the highways (based on
road class) flowing into the city in the morning would get reduced average
speeds you could apply curve like average speed*percent based on 6am (90%),
7am(75%), 8am(45%), 9am(50%), 10am(85%) and do something similar in the
evening rush. It might be too hard to figure on direction of flow in/out
bound so apply the curve to all traffic. The assumption is that the highways
are congested which will force traffic onto side streets. You might want to
also reduce the lower class speeds by say a constant 80% during rush hour."

So, what classes should I consider as highways, what classes as streets and
so on? Or What should be the pattern of speed changes in various classes?

The main focus would be, we should be routed through less congested areas
during rush hours right?

Once we finalise this model, I can write the plsql function to generate the
corresponding data.



Well in the US anyway. Also if this is OSM data then you might get a better
> clue on classes by looking to that .... OH!, look what I found in google :)
>
> http://workshop.pgrouting.org/chapters/advanced.html
>
> Looks like first digit is type and the three digits are from the classes
> table.
>
> -Steve
>
>
> On 6/12/2011 4:33 AM, Jay Mahadeokar wrote:
>
>>
>>
>> On Sun, Jun 12, 2011 at 1:32 PM, Anton Patrushev
>> <anton.patrushev at georepublic.de <mailto:anton.patrushev at georepublic.de>>
>>
>> wrote:
>>
>>    Hi Jay,
>>
>>    No, there was no specific meaning, just king of cyphering - first
>>    digit for road class and then two last digits for road type.
>>
>>
>> Hi Anton,
>>
>> So, as you said last 2 digits are for road type. I can see they are
>> mainly 00, 01, 02, 06, 08, 09, 10, 11, 12 ,14, 17.
>>
>> Road class is just 1 or 4.
>>
>> Can I differentiate major highways, minor highways, streets etc using
>> this info?
>>
>>    Anton.
>>
>>    On 6/12/11, Jay Mahadeokar <jai.mahadeokar at gmail.com
>>    <mailto:jai.mahadeokar at gmail.com>> wrote:
>>     >> Hi Jay,
>>     >>
>>     >> I think that instead of just random times, I would take a different
>>     >> approach to generate this data. If we think about "rush hour"
>>    around a
>>     >> major
>>     >> city, the highways (based on road class) flowing into the city
>>    in the
>>     >> morning would get reduced average speeds you could apply curve like
>>     >> average
>>     >> speed*percent based on 6am (90%), 7am(75%), 8am(45%), 9am(50%),
>>    10am(85%)
>>     >> and do something similar in the evening rush. It might be too
>>    hard to
>>     >> figure
>>     >> on direction of flow in/out bound so apply the curve to all
>>    traffic. The
>>     >> assumption is that the highways are congested which will force
>>    traffic
>>     >> onto
>>     >> side streets. You might want to also reduce the lower class
>>    speeds by say
>>     >> a
>>     >> constant 80% during rush hour.
>>     >>
>>     >> If we can get OSM data then it should be easy to populate the
>>    table with
>>     >> that data.
>>     >>
>>     >> -Steve
>>     >>
>>     >
>>     > I am trying to write plpgsql query to generate time-dependent data
>>     > corresponding to the ways table in pgrouting workshop. As
>>    suggested by Steve
>>     > above, instead of generating random data, I will follow patterns
>>    (see above
>>     > message) so that the data is nearer to the real worlds scenario.
>>     >
>>     > So, now I need to make distinction between highways, streets etc.
>>    I saw the
>>     > attribute class_id in ways table. It has 14 distinct values:
>>     >  class_id
>>     >
>>     > ----------
>>     >
>>     >
>>     > 102
>>     >
>>     >
>>     > 122
>>     >
>>     >
>>     > 106
>>     >
>>     >
>>     > 111
>>     >
>>     >
>>     > 108
>>     >
>>     >
>>     > 100
>>     >
>>     >
>>     > 109
>>     >
>>     >
>>     > 112
>>     >
>>     >
>>     > 101
>>     >
>>     >
>>     > 110
>>     >
>>     >
>>     > 401
>>     >
>>     >
>>     > 119
>>     >
>>     >
>>     > 117
>>     >
>>     >       114
>>     >
>>     > Any specific meaning attached to these values? I did not find any
>>     > information on the pgRouting-workshop website [1].
>>     >
>>     >
>>     > Thanks in advance.
>>     >
>>     > [1] http://workshop.pgrouting.org/chapters/topology.html
>>     >
>>     > --
>>     > Regards,
>>     > -Jay Mahadeokar
>>     >
>>
>>
>>    --
>>    Georepublic UG (haftungsbeschränkt)
>>    Salzmannstraße 44,
>>    81739 München, Germany
>>
>>    Anton Patrushev
>>    CTO
>>
>>    eMail: anton.patrushev at georepublic.de
>>    <mailto:anton.patrushev at georepublic.de>
>>
>>    Web: http://georepublic.de
>>
>>    Tel: +49 (089) 420 959 519
>>    Sip: 1959519 at sipgate.de <mailto:1959519 at sipgate.de>
>>
>>
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>>    _______________________________________________
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>>
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>>
>>
>>
>>
>> --
>> Regards,
>> -Jay Mahadeokar
>>
>>
>>
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>
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-- 
Regards,
-Jay Mahadeokar
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