[postgis-users] Help with pgRouting & PostGIS

[Nguyen Thi Van An]

Hello Green,
You can use some functions for Postgis to do some of your need : startpoint
to get x1, y1; endpoint to get x2, y2; length...; source and target are the
topology column and they are generated by function assign_vertex_id 
Hopes this helps,


Green-8 wrote:
> 
> Hello Pedro,
> 
> Thank you very much for your mail. Yes, I have created two dataset (a)
> node
> (b) edge as you said. I was looking at the sample data given in PostLBS
> which has something like
> 
> CREATE TABLE "kanagawa" (gid serial PRIMARY KEY,
> "length" numeric,
> "x1" numeric,
> "y1" numeric,
> "x2" numeric,
> "y2" numeric,
> "source" int8,
> "target" int8);
> SELECT
> AddGeometryColumn('','kanagawa','the_geom','-1','MULTILINESTRING',2);
> COPY "kanagawa" ("length","x1","y1","x2","y2","source","target",the_geom)
> FROM stdin;
> 
> In the edge data from OpenJump we have start and end nodes which will be
> source and target. Can you please point me out about how to get the rest
> of
> the columns. Which are the columns need to transfered from nodes layer and
> can I just use length(the_geom) to get the length column ?.
> 
> Thanks
> Green.
> 
> On 25/04/07, Pedro Doria Meunier <pdoria at netmadeira.com> wrote:
>>
>>  Hey Green,
>>
>>
>>
>> I have fiddled with this some time ago... (and I also was left scratching
>> my head for a while :] )
>>
>>
>>
>> Here's what I've concocted:
>>
>>
>>
>> Using OpenJump:
>>
>> There a tool called 'Planar Graph' under tools->analysis
>>
>> (uncheck create faces)
>>
>>
>>
>> You're give two layers à one with all the nodes (and their IDs) and the
>> other with the edges.
>>
>> The latter gives you the start and end nodes for each segment…
>>
>> Since pgrouting works by setting turning costs for each node… You just
>> have to add another field to this layer and set each node's turning cost…
>> ;-)
>>
>> (you could, of course, transfer the attributes from the original layer
>> (such as labels, names, etc…) to this layer…)
>>
>>
>>
>> From this point on it's a matter of deciding what you want to do under a
>> programmatical point of view…
>>
>>
>>
>> So you see you don't have to go nuts with all that unfinished topology
>> support… ;-)
>>
>>
>>
>> HTH,
>>
>> Pedro Doria Meunier
>>
>>
>>
>>
>>
>> *From:* postgis-users-bounces at postgis.refractions.net [mailto:
>> postgis-users-bounces at postgis.refractions.net] *On Behalf Of *Green
>> *Sent:* quarta-feira, 25 de Abril de 2007 11:15
>> *To:* postgis-users at postgis.refractions.net
>> *Subject:* [postgis-users] Help with pgRouting & PostGIS
>>
>>
>>
>> Hi,
>>
>> I have been using PostGIS for a while and it works great for my
>> requirement. I have roads & streets as shapefile and now, I wanted to a
>> find
>> the shortest route between locations.
>>
>> I found pgRouting during the search process. There they talk about
>> topology. They have suggested to use 3 tools for creating data for
>> pgRouting
>> and I don't have access to 2 of them. The one that is familiar to me is
>> PostGIS. I intalled the topology functions and I am struck without any
>> direction. Now what ?
>>
>> I request any one of you help me and I would greatly appreciate.
>>
>> I have shapefiles of roads and how do I create data for pgRouting ?
>>
>> Thanks
>> Green
>>
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>>
>>
> 
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