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When I run <a
href="http://docs.pgrouting.org/2.0/en/src/driving_distance/doc/dd_driving_distance.html"><code>pgr_drivingdistance</code></a>
on an small extract (578 rows) (attached) from an <a
href="http://download.geofabrik.de/north-america/us/pennsylvania.html">extract
of Pennsylvania's osm pbf file</a> not all edges are being
followed.
I first downloaded the pbf. Then I imported it with <a
href="https://github.com/pgRouting/osm2pgrouting"><code>osm2pgrouting</code></a>
<code>
<pre>osmosis --read-pbf file=pennsylvania-latest.osm.pbf --write-xml pennsylvania-latest.osm
osm2pgrouting -file pennsylvania-latest.osm -conf /usr/share/osm2pgrouting/mapconfig.xml -dbname osm3 -user jim -skipnodes -passwd hunter2
</pre>
</code>
and then running
<code>
<pre>CREATE TABLE smallways AS
SELECT * FROM ways
WHERE ST_DISTANCE(the_geom, ST_GEOMFROMTEXT('POINT(-79.900121 40.448889)', 4326)) < 0.2;
</pre>
</code>
and creating the appropriate indices to build a test environment
(the output of which
is the small extract (578 rows)(attached)).
To test <code>pgr_drivingdistance</code>, I did the following:
<code>
<pre>CREATE OR REPLACE VIEW testing AS
SELECT gid,
the_geom
FROM ( SELECT
seq,
id1 AS vertext_id,
id2 AS gid,
cost
FROM pgr_drivingdistance(
'SELECT gid AS id, source, target,
length AS cost, reverse_cost
FROM smallways',
179103,
0.5,
false,
true) ) t
INNER JOIN smallways USING (gid);
</pre>
</code>
and then loading that view into QGIS, I see the following:
<a href="cid:part5.06050408.08070207@jimkeener.com"><img
src="cid:part4.07070907.04000409@jimkeener.com"
style="width:800; clear: both"></a>
<br style="clear:both">
Why are some edges not being selected? I initially thought it was
the <code>(source, target)</code> (labels in screenshot) ordering,
but that doesn't seem to be the case, as some edges such as 148517
to the SW of the annotated starting point, seems to be in good
order.
<code><font face="sans-serif"></font><br>
<br>
<font face="sans-serif">Jim</font><br>
</code>
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