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Two additional options, if you want to expand beyond QGIS:<br>
In Spatialite there are the functions ST_StartPoint() and
ST_EndPoint(). (Same in PostGIS). So you could do a query such as:<br>
<tt><br>
SELECT line_id, ST_StartPoint(geometry) AS StartPoint,
ST_EndPoint(geometry) AS EndPoint </tt><tt><br>
</tt><tt>FROM lines</tt><tt>;<br>
<br>
</tt><tt></tt>THis returns just the geometry (POINTS), so if you
want them in a separate point table, you might do something like:<br>
<br>
<tt>CREATE TABLE end_points (pkuid primary key autoincrement,
line_id integer);</tt><tt><br>
</tt><tt>SELECT AddGeometryColumn('end_points','geometry',<EPSG
code of your CRS>, 'POINT,2); </tt><tt><br>
</tt><tt>INSERT INTO end_points (line_id, geometry) SELECT line_id,
ST_StartPoint(geometry) FROM lines;</tt><tt><br>
</tt><tt>INSERT INTO end_points (line_id, geometry) SELECT line_id,
ST_EndPoint(geometry) FROM lines;</tt><tt><br>
</tt><tt><br>
</tt><tt>
</tt>Alternately, if you need the coordinates of the endpoints:<br>
<br>
<tt>SELECT line_id, AsWKT(ST_StartPoint(geometry)),
AsWKT(ST_EndPoint(geometry)) </tt><tt><br>
</tt><tt>FROM lines;</tt><tt><br>
</tt><br>
And in addition you can also go to GRASS and use the v.to.points
module with the "use=node" in order to create a point vector of
nodes only from a GRASS line vector.<br>
<br>
So there are several ways to choose...<br>
<br>
<div class="moz-cite-prefix">On 07/01/2015 06:01 PM, CONTI Tonino
wrote:<br>
</div>
<blockquote
cite="mid:7D9132CB72671B4D8A7DB82AE416CF01FA279332BD@exchange.comune.jesi.an.it"
type="cite">
<pre wrap="">THANKS RICHARD.
DO I HAVE TO SELECT THE MAXIMUM AND MINIMUM VALUE FOR EACH ELEMENT AND DELETE THE OTHERS.
YOU KNOW IF THERE IS A FUNCTION SELECTING THE FIRST AND LAST POINT OF EACH ITEM?
TANKS
TONINO
Tonino Conti
Comune di Jesi
Sistema Informativo Territoriale
Tel 0731538312 - fax 0731538513
<a class="moz-txt-link-abbreviated" href="mailto:t.conti@comune.jesi.an.it">t.conti@comune.jesi.an.it</a>
<a class="moz-txt-link-abbreviated" href="http://www.comune.jesi.an.it/sit">www.comune.jesi.an.it/sit</a>
________________________________________
Da: Richard McDonnell [<a class="moz-txt-link-abbreviated" href="mailto:richard.mcdonnell@opw.ie">richard.mcdonnell@opw.ie</a>]
Inviato: martedì 30 giugno 2015 16.43
A: CONTI Tonino
Cc: <a class="moz-txt-link-abbreviated" href="mailto:qgis-user@lists.osgeo.org">qgis-user@lists.osgeo.org</a>
Oggetto: Re: [Qgis-user] extracting the starting point and end point from a linear geometry
Tonino,
From the toolbar...Vector, Geometry Tools, Extract Nodes.
This I think should help!
Regards,
Richard McDonnell
OPW - Ag féachaint don am atá le teacht - Ag caomhnú ón am atá thart
OPW - Looking to the future - Caring for the past
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</pre>
</blockquote>
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