<div><div dir="auto">How about the example here?</div></div><div dir="auto">Z and M should be supported.</div><div dir="auto"><br></div><div dir="auto"><div><a href="https://postgis.net/docs/manual-1.5/ST_Line_Substring.html">https://postgis.net/docs/manual-1.5/ST_Line_Substring.html</a></div></div><div dir="auto"><br></div><div dir="auto"><pre class="programlisting" style="border-width:2px 0px;font-family:"Courier New",Courier,Monaco,monospace;line-height:16px;border-color:rgb(247,147,30);border-style:solid;font-size:11px;margin-bottom:10px;margin-top:10px;overflow:auto;padding:10px;background-color:rgb(248,248,249);border-top-left-radius:2px;border-top-right-radius:2px;border-bottom-right-radius:2px;border-bottom-left-radius:2px;color:rgb(46,46,46)">
--The below example simulates a while loop in
--SQL using PostgreSQL generate_series() to cut all
--linestrings in a table to 100 unit segments
-- of which no segment is longer than 100 units
-- units are measured in the SRID units of measurement
-- It also assumes all geometries are LINESTRING or contiguous MULTILINESTRING
--and no geometry is longer than 100 units*10000
--for better performance you can reduce the 10000
--to match max number of segments you expect
SELECT field1, field2, ST_Line_Substring(the_geom, 100.00*n/length,
CASE
WHEN 100.00*(n+1) < length THEN 100.00*(n+1)/length
ELSE 1
END) As the_geom
FROM
(SELECT sometable.field1, sometable.field2,
ST_LineMerge(sometable.the_geom) AS the_geom,
ST_Length(sometable.the_geom) As length
FROM sometable
) AS t
CROSS JOIN generate_series(0,10000) AS n
WHERE n*100.00/length < 1;
</pre><pre class="programlisting" style="border-width:2px 0px;font-family:"Courier New",Courier,Monaco,monospace;line-height:16px;border-color:rgb(247,147,30);border-style:solid;font-size:11px;margin-bottom:10px;margin-top:10px;overflow:auto;padding:10px;background-color:rgb(248,248,249);border-top-left-radius:2px;border-top-right-radius:2px;border-bottom-right-radius:2px;border-bottom-left-radius:2px;color:rgb(46,46,46)"><br></pre><pre class="programlisting" style="border-width:2px 0px;font-family:"Courier New",Courier,Monaco,monospace;line-height:16px;border-color:rgb(247,147,30);border-style:solid;font-size:11px;margin-bottom:10px;margin-top:10px;overflow:auto;padding:10px;background-color:rgb(248,248,249);border-top-left-radius:2px;border-top-right-radius:2px;border-bottom-right-radius:2px;border-bottom-left-radius:2px;color:rgb(46,46,46)"><br></pre></div><div dir="auto"><br></div><div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, 15 Feb 2020 at 19:25, Alexander Gataric <<a href="mailto:gataric@usa.net">gataric@usa.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="zoom:0%"><div dir="auto">I tried to use st_segmentize but found that the m coordinate gets corrupted.<br><br></div>
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<div class="gmail_quote">On Feb 15, 2020, at 12:50 PM, Phil Bartie <<a href="mailto:philbartie@gmail.com" target="_blank">philbartie@gmail.com</a>> wrote:<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div><div dir="auto">Would ST_Segmentize() do what you are after?</div><div dir="auto"> Run it after the simplify. </div></div><div dir="auto"><br></div><div dir="auto"><div><a href="https://postgis.net/docs/ST_Segmentize" target="_blank">https://postgis.net/docs/ST_Segmentize</a></div></div><div dir="auto"><br></div><div dir="auto">Might need to use in conjunction with ST_Union()</div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto"><br></div><div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, 15 Feb 2020 at 18:44, Alexander Gataric <<a href="mailto:gataric@usa.net" target="_blank">gataric@usa.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="zoom:0%"><div dir="auto">I mean if a line is one mile long and is simplified into five 1000 foot segments, I want the longest segment to be 500 feet instead of 1000 feet.<br><br></div>
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<div class="gmail_quote">On Feb 15, 2020, at 11:47 AM, Martin Davis <<a href="mailto:mtnclimb@gmail.com" target="_blank">mtnclimb@gmail.com</a>> wrote:<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="auto">You mean you want to keep simplifying until there are no segments of length greater than the maximum? (Presumably excluding input segments already longer?)</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Feb 14, 2020, 1:57 PM Alexander Gataric <<a href="mailto:gataric@usa.net" target="_blank">gataric@usa.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="EN-US" link="blue" vlink="purple" style="zoom:0%"><div dir="auto">Is there a way to modify st_simplify to have a maximum segment length? I want to be able to limit it to 500 feet.<br><br></div>
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