<div dir="ltr"><div><div><div><div><div>Does  offset curve gives the same result? <br>(seems lile offsetting both side have same behavior)<br><br></div>Maybe you can try several buffers with increasing size?<br></div><div>
(default appears wau before 1000)<br></div><div><br></div>Also, can you try to simplify your line : each coordinates uses 15 digits, surely you don't need all of this !<br></div>(simplifying to 8 digits doesn't help).<br>
<br></div>It seems like a bad design in algorithm ?<br><br></div>Cheers,<br>Rémi-C<br></div><div class="gmail_extra"><br><br><div class="gmail_quote">2013/11/25 James David Smith <span dir="ltr"><<a href="mailto:james.david.smith@gmail.com" target="_blank">james.david.smith@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi there,<br>
<br>
Some code to illustrate my problem:<br>
<br>
1) A linestring (SRID: 27700)<br>
<br>
LINESTRING(555936.152 200920.582000002,555938.312000002<br>
200908.102000002,555943.112000001 200883.142000001,555953.192000001<br>
200839.702,555964.471999999 200798.181999998,555974.312<br>
200764.342000002,555983.912 200744.182000002,555990.554<br>
200733.721000003,555993.512 200729.062000005,555995.778000002<br>
200726.756000001,556006.952000001 200715.382000001,556024.232<br>
200698.822000002,556036.597999999 200687.931,556050.392000001<br>
200675.782000002,556055.914 200671.265000002,556071.512<br>
200658.502000002,556094.915000001 200640.537000002,556095.451000001<br>
200640.152000001,556113.992000001 200628.742000001,556138.472000001<br>
200616.502000004,556159.112000002 200605.942000002,556180.232000001<br>
200589.862000002,556207.592 200568.022000002,556217.912000002<br>
200558.182,556228.472000001 200545.702,556240.472<br>
200527.702000003,556251.992000001 200509.221999999,556253.237000001<br>
200506.732000003,556258.952 200495.302000001,556268.000000001<br>
200478.000000002,556279.592 200458.582000002,556300<br>
200431.000000002,556351.000000002 200364,556349.253 200366.234000001)<br>
<br>
2) Now I buffer it:<br>
<br>
SELECT ST_Buffer(<br>
 ST_GeomFromText(<br>
  'LINESTRING(555936.152 200920.582000002,555938.312000002<br>
200908.102000002,555943.112000001 200883.142000001,555953.192000001<br>
200839.702,555964.471999999 200798.181999998,555974.312<br>
200764.342000002,555983.912 200744.182000002,555990.554<br>
200733.721000003,555993.512 200729.062000005,555995.778000002<br>
200726.756000001,556006.952000001 200715.382000001,556024.232<br>
200698.822000002,556036.597999999 200687.931,556050.392000001<br>
200675.782000002,556055.914 200671.265000002,556071.512<br>
200658.502000002,556094.915000001 200640.537000002,556095.451000001<br>
200640.152000001,556113.992000001 200628.742000001,556138.472000001<br>
200616.502000004,556159.112000002 200605.942000002,556180.232000001<br>
200589.862000002,556207.592 200568.022000002,556217.912000002<br>
200558.182,556228.472000001 200545.702,556240.472<br>
200527.702000003,556251.992000001 200509.221999999,556253.237000001<br>
200506.732000003,556258.952 200495.302000001,556268.000000001<br>
200478.000000002,556279.592 200458.582000002,556300<br>
200431.000000002,556351.000000002 200364,556349.253<br>
200366.234000001)'), 1000, 'endcap=flat join=round');<br>
<br>
3) The result is attached as a jpg (line thickness increased to aid viewing).<br>
<br>
Any ideas please? This is related to an ongoing discussion I was<br>
having with Remi a while ago. Basically I'm buffering loads of road<br>
centrelines to create polygons. But when I do it, a small number end<br>
up with really strange buffers like this attached example. I'm at a<br>
loss as to why.<br>
<br>
Thanks<br>
<span class="HOEnZb"><font color="#888888"><br>
James<br>
</font></span><br>_______________________________________________<br>
postgis-users mailing list<br>
<a href="mailto:postgis-users@lists.osgeo.org">postgis-users@lists.osgeo.org</a><br>
<a href="http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users" target="_blank">http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users</a><br></blockquote></div><br></div>