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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Hi,</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I am having a table in which I am storing a MULTISTRING
after applying ST_union on a set of multistring data which are continuous. This
is actually the shortest path that I am determining.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Now, I am capturing real time gps coordinates. My plan is
that when the gps position deviates from the determined route it will calculate
the shortest path again from the </span></font><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>GPS</span></font><font size=2
face=Arial><span style='font-size:10.0pt;font-family:Arial'> position.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>So I am trying to find the distance of the </span></font><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>GPS</span></font><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> point from
the line ( representing the shortest path) as follows:</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Select ST_Distance(gpsdata.gpscoords,ST_line_interpolate_point(shortpath.the_geom,ST_line_locate_point(ST_LineMerge(shortpath.the_geom),
GeomFromText(‘POINT(2477850.34 7044705.10)’,2276))) from gpsdata,shortpath
where shortpath.gid=1 and gpsdata.oid=2</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The coordinates are that of one such gps point.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>But I am getting error in the ST_line_locate_point . It says</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Line_locate_point: 1<sup>st</sup> arg isn’t a line.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>But when I am running the line_locate_point with some
different table like roads table it works fine.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>So is there any other way to find the distance of a point to
a line?</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thanks</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Suman</span></font></p>
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