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<p class=MsoNormal>Hi All,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span lang=EN-US>@Regina:<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Remember you helped me with the 10 closest
units to a given point? This was it:<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>(original layers srid==4326 – I want *<b>meters</b>*
so the transform at play)<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>SELECT u.id, u.friendly_name,
u.curr_location, t.oid, distance(transform(u.curr_location,32628),
transform(t.geometry, 32628)) AS thedistance, u.mobile FROM units AS u, (SELECT
roads.oid, roads.geometry FROM roads WHERE name=’N17’ LIMIT 1) AS t
<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>ORDER BY thedistance LIMIT 10;<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>(this query returns the 1<sup>st</sup>
found line segment labelled ‘N17’ which is 68Kms away when the unit
is actually 1.8 meters away from the closest line segment of the same label)<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>@All<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>This actually returns the FIRST occurrence of
‘N17’ (the sample).<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>This is *<b>NOT</b>* necessarily the
closest road to the unit’s current location.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I’ve melted half-a-dozen neurons (mainly
due to tiredness at the time of this writing :] )trying to figure out how can I
implement the distance bit in the sub-query…<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Given example for ONE unit:<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>select u.friendly_name,
distance(transform(u.curr_location, 32628), <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>transform(geometry,32628)) as thedistance <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>from pt_mainland_roads as r, units as u <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>where name='N17' AND u.curr_location
&& r.geometry order by thedistance LIMIT 1;<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>(this returns the correct result)<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>So to summarize things:<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>I need help with a query that returns the *<b>FIRST
TEN</b>* units to the *<b>closest given</b>* road. <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>(Keep in mind that multiple line segments
with the same name exist – I need the closest)<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Will try again tomorrow with a clear head
but in the meantime:<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Any help would be most appreciated!<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Best regards,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Pedro Doria Meunier.<o:p></o:p></span></p>
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