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<p>Trying to address this SE question:</p>
<p><br>
</p>
<p><a class="moz-txt-link-freetext" href="https://gis.stackexchange.com/questions/319319/how-to-apply-smoothing-filter-only-to-way-bigger-than-specified-number-of-nodes">https://gis.stackexchange.com/questions/319319/how-to-apply-smoothing-filter-only-to-way-bigger-than-specified-number-of-nodes</a></p>
<p><br>
</p>
<p>I tried to apply v.generalize to a subset of area features, using
a where clause, but it doesn't seem to be working. All features
are generlized, as if the where clause is being ignored. Here's an
example from the nc_basic_sm MAPSET:</p>
<p><br>
</p>
<p><tt>micha@TP480:~$ v.extract geology output=my_geology --o
where="GEO_NAME='Qp'"</tt><tt><br>
</tt><tt>WARNING: Vector map <my_geology> already exists and
will be overwritten</tt></p>
<p><tt>.....</tt></p>
<p><tt><br>
</tt></p>
<p><tt>micha@TP480:~$ v.db.addcolumn my_geology column="area_sqkm
DOUBLE"</tt></p>
<p><tt>micha@TP480:~$ v.to.db my_geology option=area
column=area_sqkm unit=kilometer</tt><tt><br>
</tt><tt>WARNING: Values in column <area_sqkm> will be
overwritten</tt><tt><br>
</tt><tt>.....</tt><tt><br>
</tt><tt>326 records updated/inserted (layer 1)</tt></p>
<p><tt><br>
</tt></p>
<p><tt># Only 21 features are larger than 10 sq.km.:</tt><tt><br>
</tt></p>
<p><tt>micha@TP480:~$ v.db.select -c my_geology column=area_sqkm
where="area_sqkm>10" | wc -l</tt><tt><br>
</tt><tt>21</tt></p>
<p><tt><br>
</tt></p>
<p><tt>micha@TP480:~$ v.generalize my_geology
output=my_geology_smooth type=area method=douglas thresh=100
where="area_sqkm>10" --o</tt></p>
<p><tt>....</tt><tt><br>
</tt></p>
<p><tt>v.generalize complete. Number of vertices for selected
features reduced</tt><tt><br>
</tt><tt>from 44238 to 7540 (17% remaining)</tt></p>
<p><br>
</p>
<p>Now viewing both my_geology and my_geology_smooth shows that
*all* features were smoothed. Including those island polygons that
were much smaller than 10 sq.km.<br>
</p>
<p><br>
</p>
<p>Am I missing something?</p>
<p><br>
</p>
<pre class="moz-signature" cols="72">--
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918</pre>
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