[pgrouting-users] Regarding pgrouting and postgis for shortest path
Raghavan Krishnasamylakshmanaperumal
rkrish20 at uic.edu
Thu Jan 16 13:54:31 PST 2014
Steve,
Thanks for pointing out various resources, probably I didn't explain about
my data properly. So the data which I have is not just two points, I have
collected data from my and some of my friend's
runkeeper<http://runkeeper.com/>GPS traces for various activities like
running, walking, biking in and
around Chicago. I have all these GPS points(longitude,latitude) information
with me. What I am trying to find is the shortest path given any two points
from the data which I have collected.
Thanks,
Raghavan
On Thu, Jan 16, 2014 at 3:42 PM, Stephen Woodbridge <woodbri at swoodbridge.com
> wrote:
> On 1/16/2014 4:31 PM, Raghavan Krishnasamylakshmanaperumal wrote:
>
>> Steve,
>> Thanks for your reply, I think I almost understood. So you say that
>> having only these GPS point may not help me I should also have the
>> network map corresponding to these GPS points using which I can figure
>> out the shortest path?
>>
>
> if you only have two point on the earth and nothing more what is the
> shortest path. "Path" implies that you have a network of paths and that you
> want to find the the shortest path within the network. If you only have the
> points and no network then you can not find the shorth path in the network,
> because you do not have one.
>
> The way things works is that we take a point and find the nearest edge ot
> node in our network for that point and that then becomes the start or end
> point in the network. Dijkstra then searchs the network for the shortest
> path between two points.
>
>
> So right now I have only these GPS points, how should I proceed further
>> to figure out the shortest path between any two GPS points from my data.
>>
>
> You can't do anything with just these points. You have to make them to a
> network and then search for a solution within that network.
>
> So you have to find network data that you can use for your area of
> interest. You might look at OSM data and osm2pgrouting to load it into
> pgRouting.
>
> You could also look into using Project-OSRM (requires 64bit HW) which is
> the router used by OSM.
>
>
> I am open to use any database/framework/language so please suggest me
>> how to proceed further and I am concerned about scalability or other
>> factors because this is just a proof of concept(course project) which I
>> am trying to build.
>>
>
> pgRouting
> Project-OSRM
> google: java dijkstra
>
> There are lots of choices, but all require that you have network data.
>
> -Steve
>
> Thanks,
>> Raghavan
>>
>>
>> On Thu, Jan 16, 2014 at 12:21 PM, Stephen Woodbridge
>> <woodbri at swoodbridge.com <mailto:woodbri at swoodbridge.com>> wrote:
>>
>> On 1/16/2014 12:46 PM, Raghavan Krishnasamylakshmanaperumal wrote:
>>
>> Recently I started using PostGIS for my academic project which is
>> a
>> route recommendation system. I have stored the data in the
>> following format.
>> /
>> /
>> /gid=>integer, activity=>varchar(20), geom geometry(Point,4326)/
>>
>>
>> geometry points are longitude and latitude information, for
>> example if
>> you record your Running activity using a gps device, each point
>> record
>> (longitude & latitude) is stored in the geom column.
>>
>>
>> The shortest distance between two points is a straight line unless
>> you want to constrain the problem to the shortest distance along
>> some road or path network.
>>
>> If it is constrained to a networks of paths then you have to have
>> the data for that network available.
>>
>> In the case of pgRouting, you have to load the network data and
>> prepare it for routing, then you can use you points as the start and
>> end points of a route and ask pgRouting to fins the shortest path
>> between them along the network.
>>
>>
>> I need to find the shortest path(using Dijkistra's) between any
>> two geom
>> points from this data set and I am trying to automate this using
>> some
>> programming language like Java.
>>
>>
>> With Java you can connect to the database and issue simple queries
>> to pgRouting to get your results. If you are looking for a Java
>> library to solve Dijkstra problems then this is not pgRouting. Also
>> if you are using a Java library you will still need to load the
>> network of paths that you want to solve you queries against.
>>
>> Hope this helps,
>> -Steve
>>
>> Please can you suggest me how to make use of pgrouting and
>> postgis data
>> to figure out the shortest path. Is there any library available to
>> automate this using Java. I am totally stuck on my project and
>> finally
>> came to know about this mailing list.
>>
>>
>> --
>> Thanks and Regards,
>> Raghavan KL
>>
>>
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>>
>> --
>> Thanks and Regards,
>> Raghavan KL
>>
>>
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--
Thanks and Regards,
Raghavan KL
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