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<DIV dir=ltr align=left><SPAN class=669014320-27042007><FONT color=#0000ff
size=2>Which involves learning PGSQL. Which I'll have to do,
eventually.</FONT></SPAN></DIV>
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size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=669014320-27042007><FONT color=#0000ff
size=2>It's not clear to me that this approach would work for polygons, but it's
not clear to me that I'm having this problem with anything but linestrings, so
that probably doesn't matter. (I sometimes have to draw maps showing
hundreds of linear features criss-crossing over an area. When I have
hundreds of two-dimensional overlapping features, my maps always seem to involve
displaying just a few of them.)</FONT></SPAN></DIV>
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class=669014320-27042007><FONT color=#0000ff
size=2></FONT></SPAN> </DIV><BR>
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<FONT face=Tahoma size=2><B>From:</B>
postgis-users-bounces@postgis.refractions.net
[mailto:postgis-users-bounces@postgis.refractions.net] <B>On Behalf Of
</B>David William Bitner<BR><B>Sent:</B> Friday, April 27, 2007 2:08
PM<BR><B>To:</B> PostGIS Users Discussion<BR><B>Subject:</B> Re:
[postgis-users] Optimizations: splitting large features<BR></FONT><BR></DIV>
<DIV></DIV>Jeff--<BR><BR>The linear referencing functions along with a bit of
PL/PGSQL can accomplish this pretty well with a basic loop to divide a segment
either by a distance or into a specific number of segments to split the linear
feature into. <BR><BR>David<BR><BR>
<DIV><SPAN class=gmail_quote></SPAN>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid"><BR>The
other is to split features apart. Instead, for example, of having
<BR>one feature representing a river that snakes around over a large
area,<BR>and hence has to be included in nearly every spatial query, break
it<BR>apart into multiple features each of which represents a short segment
of <BR>the river.<BR><BR></BLOCKQUOTE></DIV></BLOCKQUOTE></BODY></HTML>