[GraphHopper] Graphhopper using dijkstra's algo directly with graph

[Quinton Anderson]

Hi Peter,

So I have a case where I would like to manipulate the routing algorithm through the introduction of POIs. I would like to force that even shortest routes go via POIs that are within a given distance of the ideal route, even with contraction hierarchies. 

Any thoughts? 

On 09 May 2013, at 9:09 PM, Peter K wrote:

> Hi Quinton,
> 
> you will be able to import POIs into graphhopper. Then you'll be able to
> do something like
> List<Path> resultingPaths = graphhopper.route(fromLocation, "restaurant");
> to get a list of paths sorted by distance or time.
> 
> For the faster algorithm however (currently contraction hierarchies) one
> needs to specify the location of the POIs explicitly.
> 
> Regards,
> Peter.
> 
>> Hi Peter,
>> 
>> Search for the points and route via those points? 
>> 
>> Thanks. 
>> On 09 May 2013, at 8:49 PM, Peter K wrote:
>> 
>>> [forwarded to mailing list]
>>> 
>>> Hi Zongjie,
>>> 
>>> have a look into the low level API:
>>> https://github.com/graphhopper/graphhopper/wiki/Low-Level-API
>>> 
>>> and the relative efficient one-to-many dijkstra:
>>> https://github.com/graphhopper/graphhopper/blob/master/core/src/main/java/com/graphhopper/routing/DijkstraOneToMany.java
>>> where the distance limit is already implemented ('limit')
>>> 
>>> In the near future one will be able to search for points of interests in
>>> a certain radius, which will be probably similar to what you want.
>>> 
>>> Regards,
>>> Peter.
>>> 
>>>> Hi Peter,
>>>> 
>>>> I have been using your graphhopper api for my final year project and
>>>> it has been great! However, I need to make some changes to my project
>>>> which I would like to request for your help.
>>>> 
>>>> I know that graphhopper is providing routing capabilities through
>>>> reading of the graph of a map and using the various algorithms to
>>>> return an array of geopoints of the calculated path.
>>>> 
>>>> What I would need your help on is may I know if i can directly access
>>>> the graph and apply the dijkstra's algorithm on it? Because what I
>>>> actually need is geopoints that are of a certain distance away from
>>>> the current location.
>>>> 
>>>> For example: I am at point A, and I request for the road distance of
>>>> 5KM away from point A.
>>>> 
>>>> I was thinking that by using the dijkstra's algo I would be able to
>>>> traverse through the nodes of the graph till I find all the 5KM nodes
>>>> that are away from the current location's node.
>>>> 
>>>> Currently I am using your graphhopper API to get the distance and
>>>> geopoints that are of fixed angles from the current location. Let's
>>>> say 0 degrees, 90 degrees, 180 degrees and 270 degrees. So I will get
>>>> 4 routes using your API which I will then access the individual route
>>>> to find the 5KM geopoints I required to get my 5KM points away from
>>>> the current location.
>>>> 
>>>> Is there any way I can use your dijkstra's algo and access the graph
>>>> directly which then can provide me with the distance and geopoints of
>>>> each node it traversed using the algo. I believe with this, I would be
>>>> able to get all the geopoints that are of certain distance away from
>>>> the current location more effectively and efficiently!
>>>> 
>>>> Thank you for taking your time to read this and I hope to receive your
>>>> kind response soon!
>>>> 
>>>> Best Regards,
>>>> Zongjie Ng
> 
> 
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