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Hi,<br>
<br>
As Sandro suggested, you can use ST_Azimuth.<br>
<br>
I tried on myself and came up which a result, there might be a
shorter way.<br>
<br>
First, I created a view with the azimuth:<br>
<br>
CREATE OR REPLACE VIEW azimuth_view AS<br>
SELECT
id,ST_Azimuth(ST_PointN(wkb_geometry,1),ST_PointN(wkb_geometry,2))*180/pi()
AS azimuth FROM mytable;<br>
<br>
This supposes you have only 1 segment on each line (of course!)<br>
<br>
Then, I test the difference between the azimuth and I give all
parallels combinations with a given tolerance:<br>
<br>
CREATE OR REPLACE VIEW parallel_view AS<br>
SELECT A1.id, A2.id AS parallel <br>
FROM azimuth_view A1, azimuth_view A2<br>
WHERE A1.id != A2.id<br>
AND (abs(A1.azimuth-A2.azimuth) <= tolerance <br>
OR abs(A1.azimuth-A2.azimuth)-360 <= tolerance <br>
OR abs(A1.azimuth-A2.azimuth)+360 <= tolerance );<br>
<br>
You can do similar for orthogonal lines then.<br>
<br>
PS: I tried with modulo but it does not accept double precision,
only integer. Depending on wanted tolerance, this might not be
enough!<br>
<br>
Cheers,<br>
<br>
Denis<br>
<br>
<br>
On 02/06/2012 12:45 PM, Sindile Bidla wrote:
<blockquote
cite="mid:CA+fb49YGC_p4dNXfGx93eXcKMQ8YD1DNVRybD5wh=+TGY2_+Pg@mail.gmail.com"
type="cite">Anyone who can offer advice on on building a query to
accomplish the following within the same line feature - roads:
<div><br>
</div>
<div>1. create a new table or view of all line features that are
parallel to a selected line feature within the same line feature</div>
<div><br>
</div>
<div>2. create a new table or view of all line features that
are perpendicular to a selected line feature within the same
line feature</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
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