[postgis-users] points to lines [Clarification]

[Kevin Neufeld]

If I understand you correctly, your link table already contains the necessary data to create a linestring (node_1/node_2 
or startpoint/endpoint).  You could denormalize your link table to contain a geometry column or create a new table.

CREATE TABLE lines AS
SELECT
    links.id,
    links.weight,
    ST_MakeLine(a.the_geom, b.the_geom) AS the_geom
FROM links, nodes a, nodes b
WHERE links.node_1 = a.node_id
AND links.node_2 = b.node_id;

-- Kevin

ahmed at elegantdesigns.ca wrote:
> i am resubmitting this as I missed an important fact.
> 
> Hello list,
> 
> ** I have a [edit]non geometric[/edit] table in the following format:
> 
> id    node_1    node_2    weight
> 1     1         2         5.4
> 2     1         3         2
> 3     2         4         6
> 4     4         4         1
> 
> 
> the table is about 2,000 rows long.
> 
> ** I also have a point table 
> gid    the_geom    node_id
> -      -           -
> 
> 
> i was wondering what query should i do so i can create
> * a line table between the corresponding nodes, and add to that
> * a weight field/attribute that corresponds to the newly created link
> 
> Thank you,
> dassouki
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