On 6/21/07, <b class="gmail_sendername">Rodrigo Martín LÓPEZ GREGORIO</b> <<a href="mailto:rodrigomlg@gmail.com">rodrigomlg@gmail.com</a>> wrote:<div><span class="gmail_quote"></span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi Pradeep<br><br>I don't know what you exactly mean by midpoint of a MULTILINESTRING. If what you are looking for is the point on the multilinestring located half way on a imaginary linestring that have the total length of the MULTILINESTRING and is formed by sewing together
constituent linestrings I can write a function that do this. </blockquote><div><br>Yes. this is what I am looking for. <br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Must it fill the gaps between end point of first linestring and start point of second linestring (i.e. consider the space between consecutive linestrings as part of this imaginary linestring)?</blockquote><div><br>The dataset that I have doesn't have any gaps between linestrings that make up the multilinestring. Here is a sample:
<br>MULTILINESTRING((77.6177520751953 12.8762445449829,77.6180953979492 12.8769254684448,77.6182174682617 12.8771991729736,77.6182708740234 12.877254486084,77.6<br>183853149414 12.877293586731,77.6186065673828 12.8773241043091
,77.6188049316406 12.8773641586304,77.6189193725586 12.8774423599243,77.6190490722656 12.877568<br>2449341,77.6192092895508 12.8777647018433,77.6192932128906 12.8778190612793,77.6194458007812 12.8778419494629,77.6196899414062
12.8778429031372,77.6200714111<br>328 12.8777952194214,77.6207504272461 12.8777093887329,77.6210403442383 12.8776388168335,77.6211013793945 12.8775682449341,77.6212387084961 12.8774185180664,<br>77.6214828491211 12.87730884552
,77.6220855712891 12.87717628479,77.6224746704102 12.877121925354,77.6232223510742 12.8771133422852,77.6239013671875 12.877034<br>1873169,77.6239318847656 12.8770303726196))<br><br>which is actually a continuous line. The only reason this got in as a Multilinestring is because the the original shapefile provided to shp2pgsql was having Multilinestrings as the default data type.
<br></div><br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> If you have any other detail about the function you want tell me.
</blockquote><div><br>Thanks in advance.<br><br>- Pradeep</div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><span class="e" id="q_1134e5dd890b9cdd_2">
<br><div><span class="gmail_quote">On 6/21/07, <b class="gmail_sendername">Pradeep B V</b> <<a href="mailto:pradeepbv@gmail.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">pradeepbv@gmail.com
</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Is there any other function equivalent to the <span>line_interpolate_point(the_geom, 0.5) to find the midpoint of a MULTILINESTRING?<br><br>the </span><span>line_interpolate_point works only with LINESTRINGS.<br><span>
<br>- Pradeep B V
<br><a href="http://www.btis.in" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">www.btis.in</a><br></span></span><div><span><span><br></span><br><div><span class="gmail_quote">
On 6/21/07, <b class="gmail_sendername">Rodrigo Martín LÓPEZ GREGORIO</b> <<a href="mailto:rodrigomartin@lopezgregorio.com.ar" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
rodrigomartin@lopezgregorio.com.ar</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi Matt.<br><br>I think what you want may be:
<br><br><span>line_interpolate_point(the_geom,0.5)<br><br>(or ST_</span><span>line_interpolate_point(the_geom,0.5) depending on your Postgis version)</span>
<br><span><br>where the_geom is a linestring and 0.5 means half of the total 2d length of the linestring.<br><br>You can reed more details in the documentation:<br><br><a href="http://postgis.refractions.net/docs/ch06.html#line_interpolate_point" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
http://postgis.refractions.net/docs/ch06.html#line_interpolate_point</a><br><br>Rodrigo<br></span><br><div><span class="gmail_quote">On 6/21/07, <b class="gmail_sendername">Matt Doughty</b> <<a href="mailto:matt.doughty@geograma.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
matt.doughty@geograma.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div link="blue" vlink="purple" lang="ES">
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<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;" lang="EN-GB">Hi List,</span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;" lang="EN-GB"> </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;" lang="EN-GB">Is there a function in PostGIS that finds the
midpoint of a line?</span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;" lang="EN-GB"> </span></font></p>
<p><font face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial;" lang="EN-GB">Matt</span></font></p>
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<p><font color="#2e3a75" face="Arial" size="3"><span style="font-size: 12pt; font-family: Arial; color: rgb(46, 58, 117);" lang="EN-GB">Matt Doughty</span></font><span lang="EN-GB"></span></p>
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A S.L.</span></font><font face="Arial"><span style="font-family: Arial;"></span></font></p>
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