Hi Jody,

Meantime i got some results using BasicDirectedLineGraphGenerator and 
DirectedDijkstraIterator and find way to tell graph if some edge is one or 
two way.
I understand that i must have information about direction in my data,
however 
i am curious how is it specified in GIS world? I mean what is common way 
to specify street direction in GIS world?

Thank you for all your help!

Best regards.


Jody Garnett-2 wrote:
> 
> Hi again:
> 
> The advice was to go through the test cases and look for an example; I  
> just pointed out an example test case that seemed to have something
> to do with direction :-)
> 
> Your data should have some information about the "direction" one way  
> or two way; and if it is one way you will need to either:
> - check the data to see if it says which direction
> - assume that the start of your line string is the start; and the end  
> of the line string is the end ...
> 
> Jody
> 
> On 12/08/2009, at 11:14 PM, iceDice wrote:
> 
>>
>> Hello,
>>
>> If i understand you Jody i need to use OptDirectedGraphBuilder instead
>> BasicLineGraphBuilder,
>> and to add edges twice for two way streets and once for one way  
>> streets?
>> For example for two way streets:
>>
>>    OptDirectedGraphBuilder graph_builder = new  
>> OptDirectedGraphBuilder();
>>    OptDirectedNode n1 = (OptDirectedNode) graph_builder.buildNode();
>>    OptDirectedNode n2 = (OptDirectedNode) graph_builder.buildNode();
>>
>>    DirectedEdge e = (DirectedEdge) m_builder.buildEdge(n1, n2);
>>    m_builder.addEdge(e);
>>    e = (DirectedEdge) m_builder.buildEdge(n2, n1);
>>    m_builder.addEdge(e);
>>
>> However i am confused here because i have line segments as input  
>> data and
>> there is no way to specify coordinates of start and end point to
>> OptDirectedNode nodes.
>> I suppose that start end end point of every line segment should be  
>> somehow
>> mapped to
>> OptDirectedNode n1 and n2?
>>
>> Best regards.
>>
>>
>> Jody Garnett-2 wrote:
>>>
>>> My understanding is you need to construct a graph of one way edges;
>>> and rather then one way streets being a special case - it is the two
>>> way streets that are special (you will need to add them to your graph
>>> twice; once in each direction).
>>>
>>> I would start by checking the test cases for examples of this ... I
>>> see one test for OptDirectedGraphBuilderTest that may be a good place
>>> to start?
>>>
>>> Jody
>>>
>>> On 12/08/2009, at 8:29 PM, iceDice wrote:
>>>
>>>>
>>>> Hello,
>>>>
>>>> These days i tried to play with GeoTools graph module and
>>>> DijkstraShortestPathFinder in
>>>> order to find the best route between two points on map.
>>>> I used BasicLineGraphGenerator to create graph from line segments
>>>> which are
>>>> created from
>>>> features. I also used DijkstraShortestPathFinder(graph, source,
>>>> weighter) to
>>>> find the best path
>>>> between source and destination node. I also succeed to create
>>>> shapefile
>>>> which represents best
>>>> path and display route on the map.
>>>>
>>>> Now i am trying to create graph which will take into consideration
>>>> one way
>>>> streets, but i can't see
>>>> any way how to specify one way streets to Dijkstra algorithm. I
>>>> searched
>>>> forum and find out that i
>>>> should use DijkstraShortestPathFinder(graph.getGraph(),Iterator) and
>>>> define
>>>> iterator as
>>>> DirectedDijkstraIterator. However i have no idea how to do that, and
>>>> i don't
>>>> see how i
>>>> can specify that some line segment(s) are one-way and others are
>>>> not, and
>>>> which street direction is banned.
>>>>
>>>> I tried to find something about this issue in user guide but there  
>>>> is
>>>> nothing about it and because of that I am
>>>> ready to put my final work as tutorial on wiki or something if i
>>>> succeed to
>>>> get results...
>>>>
>>>> I will be very grateful if someone can help me,
>>>>
>>>> Best regards.
>>>> -- 
>>>> View this message in context:
>>>> http://n2.nabble.com/DirectedDijkstra-tp3429853p3429853.html
>>>> Sent from the geotools-gt2-users mailing list archive at Nabble.com.
>>>>
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>>
>> -- 
>> View this message in context:
>> http://n2.nabble.com/DirectedDijkstra-tp3429853p3430612.html
>> Sent from the geotools-gt2-users mailing list archive at Nabble.com.
>>
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