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<p>Maybe It would be a good idea to use the idiosyncrasy of the
function St_Union() . St_Union merges all geometries of a table
but it also re-structures the merged geometry in a way, that it is
possible to obtain all the segments based on the intersection
points of the previous geometries.</p>
<p>Using the test_graph table of the example we can obtain the 4
segments combining st_dump with st_union.</p>
<p>select (st_dump(st_union(geom))).geom from test_graph<br>
</p>
<p><br>
</p>
<div class="moz-signature"><span style="font-size:8.5pt">
<b>Toni Hernández Vallès</b>
<br>
Servei de Sistemes d'Informació Geogràfica i Teledetecció<br>
-<br>
Universitat de Girona<br>
<b>SIGTE</b><br>
-<br>
Pl. Ferrater Mora 1<br>
17071 Girona<br>
Tel +34 972 418 039 (7026 intern)<br>
<a href="mailto:toni.hernandez@udg.edu">toni.hernandez@udg.edu</a>
<br>
<br>
<a href="http://www.sigte.udg.edu">http://www.sigte.udg.edu</a><br>
Twitter <a href="http://twitter.com/SIGTE_UDG">http://twitter.com/SIGTE_UDG</a><br>
<br>
</span></div>
<div class="moz-cite-prefix">El 16/03/2018 a les 04:24, Daniel Kastl
ha escrit:<br>
</div>
<blockquote type="cite"
cite="mid:CABXBSH-4yfJcQNdKVsuS=cka-4kY-Zqe7wktFPtfRwqP4wcsvg@mail.gmail.com">
<div dir="ltr">Thank you for reporting the issue and the easy to
reproduce test case!
<div><br>
</div>
<div>I tried with a different projection, but the issue
remained.</div>
<div>I think, it's better to track this in the pgRouting Github
repository, so I created the following issue: <a
href="https://github.com/pgRouting/pgrouting/issues/1009"
moz-do-not-send="true">https://github.com/pgRouting/pgrouting/issues/1009</a></div>
<div><br>
</div>
<div>Best regards,</div>
<div>Daniel</div>
<div><br>
</div>
<div><br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Mar 16, 2018 at 12:03 AM, Toni
Hérnández <span dir="ltr"><<a
href="mailto:toni.hernandez@udg.edu" target="_blank"
moz-do-not-send="true">toni.hernandez@udg.edu</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<p>Hello,</p>
<p>I have been trying to make some sense of the function
pgr_nodenetwork, but I haven't succeeded. <br>
</p>
<p>Based on the documentation, this function "Nodes an
network edge table.(...). What we mean by “noded” is
that at every intersection in the road network all the
edges will be broken into separate road segments"</p>
<p>I have been doing tests for the last couple of days.
You can reproduce a simple one, by executing the
following SQL statements. <br>
</p>
<p><br>
</p>
<p>-- Create test_graph table and insert two geometries<br>
</p>
<p>SET CLIENT_ENCODING TO UTF8;<br>
SET STANDARD_CONFORMING_STRINGS TO ON;<br>
BEGIN;<br>
CREATE TABLE "test_graph" (gid serial,<br>
"id" numeric(10,0),<br>
"nom" varchar(80));<br>
ALTER TABLE "test_graph" ADD PRIMARY KEY (gid);<br>
SELECT AddGeometryColumn('','test_<wbr>graph','geom','25831','<wbr>LINESTRING',2);<br>
INSERT INTO "test_graph" ("id","nom",geom) VALUES
('3',NULL,'<wbr>0102000020E764000008000000F281<wbr>433F6B731A41C84583B86985514159<wbr>2275DD14731A41C89C7A7D73855141<wbr>B3E5D70CD3721A4164B56816808551<wbr>41BFC2A67BBE721A419A3856BE8585<wbr>514137F861B0A1721A41D72C1EC58F<wbr>855141D87C445995721A413DC21EB6<wbr>968551416D2458939D721A41DFF4EF<wbr>E89D85514137F861B0A1721A411578<wbr>DD90A3855141');<br>
INSERT INTO "test_graph" ("id","nom",geom) VALUES
('5',NULL,'<wbr>0102000020E76400000900000065D6<wbr>DA5A51701A410D5914A88B855141DA<wbr>9E3C70E5701A4106E8394987855141<wbr>ADE2BBDC85711A415E9B857C858551<wbr>41C32F009B0D721A416B2643758485<wbr>514150B2FF8D78721A41A8C313B784<wbr>855141BFC2A67BBE721A419A3856BE<wbr>85855141930626E85E731A4135FA4C<wbr>92888551414E90077728741A418D04<wbr>908A90855141A5E6108797741A41F3<wbr>99907B97855141');<br>
COMMIT;<br>
ANALYZE "test_graph";<br>
<br>
-- Try to node the network.<br>
select pgr_nodenetwork ('test_Graph', 0.01, 'gid',
'geom');<br>
</p>
<p><br>
</p>
<p>You can see the geometries on images, before (<a
class="m_-5734464212881095005moz-txt-link-freetext"
href="http://sigserver4.udg.edu/apps/original_geometries.png"
target="_blank" moz-do-not-send="true">http://sigserver4.udg.edu/<wbr>apps/original_geometries.png</a>)
and after (<a
class="m_-5734464212881095005moz-txt-link-freetext"
href="http://sigserver4.udg.edu/apps/noded_geometries.png"
target="_blank" moz-do-not-send="true">http://sigserver4.udg.edu/<wbr>apps/noded_geometries.png</a>),
the noding proces.</p>
<p>The result, is a set of 6 rows but the segments
generated are not the expected ones.</p>
<p>Does anyone know what's happening here?</p>
<p>Thanks for your help.<br>
</p>
<div class="m_-5734464212881095005moz-signature">-- <br>
<span style="font-size:8.5pt"> <b>Toni Hernández Vallès</b>
<br>
Servei de Sistemes d'Informació Geogràfica i
Teledetecció<br>
-<br>
Universitat de Girona<br>
<b>SIGTE</b><br>
-<br>
Pl. Ferrater Mora 1<br>
17071 Girona<br>
Tel <a href="tel:+34%20972%2041%2080%2039"
value="+34972418039" target="_blank"
moz-do-not-send="true">+34 972 418 039</a> (7026
intern)<br>
<a href="mailto:toni.hernandez@udg.edu"
target="_blank" moz-do-not-send="true">toni.hernandez@udg.edu</a>
<br>
<br>
<a href="http://www.sigte.udg.edu" target="_blank"
moz-do-not-send="true">http://www.sigte.udg.edu</a><br>
Twitter <a href="http://twitter.com/SIGTE_UDG"
target="_blank" moz-do-not-send="true">http://twitter.com/SIGTE_UDG</a><br>
<br>
</span></div>
</div>
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-- <br>
<div class="gmail_signature" data-smartmail="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr"><span
style="font-family:arial,sans-serif;font-size:13px;border-collapse:collapse">Georepublic
UG & Georepublic Japan<br>
eMail: <a href="mailto:daniel.kastl@georepublic.de"
style="color:rgb(66,99,171)" target="_blank"
moz-do-not-send="true">daniel.kastl@georepublic.de</a><br>
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target="_blank" moz-do-not-send="true">https://georepublic.info</a></span>
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