self-hosted/postgis
self-hosted/postgis
1
0
Fork 0
mirror of https://git.osgeo.org/gitea/postgis/postgis synced 2024-10-25 17:42:38 +00:00
Code Issues Packages Projects Releases Wiki Activity

need more pictures :), visual examples for st_offsetcurve

Browse source 
git-svn-id: http://svn.osgeo.org/postgis/trunk@7668 b70326c6-7e19-0410-871a-916f4a2858ee
This commit is contained in:
Regina Obe 2011-07-25 12:13:12 +00:00
parent 2b8670820c
commit ae71ac49d4
6 changed files with 98 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
doc/html/image_src/Makefile.in
View file

@ -83,6 +83,10 @@ IMAGES= \
../images/st_longestline01.png \
../images/st_longestline02.png \
../images/st_longestline03.png \
../images/st_offsetcurve01.png \
../images/st_offsetcurve02.png \
../images/st_offsetcurve03.png \
../images/st_offsetcurve04.png \
../images/st_minimumboundingcircle01.png \
../images/st_sharedpaths01.png \
../images/st_sharedpaths02.png \

2
doc/html/image_src/st_offsetcurve01.wkt Normal file
View file

@ -0,0 +1,2 @@
Style1-thinline;LINESTRING (154 6, 134 6, 114 6, 94 6, 74 6, 54 6, 34 6, 14 6, 10 6, 8 6, 7 7, 6 8, 6 10, 6 30, 6 50, 6 70, 6 90, 6 110, 6 130, 6 150, 6 170, 6 185)
Style2-thinline;LINESTRING(154 -9,8 -9,2.25974851452365 -7.8581929876693,-2.60660171779821 -4.60660171779821,-4.60660171779821 -2.60660171779821,-7.85819298766932 2.2597485145237,-9 8,-9 185)

2
doc/html/image_src/st_offsetcurve02.wkt Normal file
View file

@ -0,0 +1,2 @@
Style1-thinline;LINESTRING (154 6, 134 6, 114 6, 94 6, 74 6, 54 6, 34 6, 14 6, 10 6, 8 6, 7 7, 6 8, 6 10, 6 30, 6 50, 6 70, 6 90, 6 110, 6 130, 6 150, 6 170, 6 185)
Style2-thinline;LINESTRING(21 185,21 21,154 21);

2
doc/html/image_src/st_offsetcurve03.wkt Normal file
View file

@ -0,0 +1,2 @@
Style1-thinline;LINESTRING (154 6, 134 6, 114 6, 94 6, 74 6, 54 6, 34 6, 14 6, 10 6, 8 6, 7 7, 6 8, 6 10, 6 30, 6 50, 6 70, 6 90, 6 110, 6 130, 6 150, 6 170, 6 185)
Style2-thinline;LINESTRING(154 -9,8 -9,-2.60660171779821 -4.60660171779821,-4.60660171779821 -2.60660171779821,-9 8,-9 185);

2
doc/html/image_src/st_offsetcurve04.wkt Normal file
View file

@ -0,0 +1,2 @@
Style1-thinline;LINESTRING(154 -9,1.78679656440358 -9,-9 1.78679656440358,-9 185)
Style1-thinline;LINESTRING(21 185,21 21,154 21);

89
doc/reference_processing.xml
View file

@ -288,7 +288,7 @@ MULTIPOLYGON(((-1 2,3 4,5 6,-1 2)),((-1 2,2 3,5 6,-1 2))) | POLYGON((-1 2,5 6,3
<refname>ST_OffsetCurve</refname>
<refpurpose>
Return an offset line at a given distance and side from an input line.
Return an offset line at a given distance and side from an input line. Useful for computing parallel lines about a center line
</refpurpose>
</refnamediv>
@ -359,12 +359,95 @@ This function ignores the third dimension (z) and will always give a
<para>Compute an open buffer around roads</para>
<programlisting>
SELECT ST_Union(
ST_OffsetCurve(f.the_geom, f.width/2, "quad_segs=4 join=round"),
ST_OffsetCurve(f.the_geom, -f.width/2, "quad_segs=4 join=round")
ST_OffsetCurve(f.the_geom, f.width/2, 'quad_segs=4 join=round'),
ST_OffsetCurve(f.the_geom, -f.width/2, 'quad_segs=4 join=round')
) as track
FROM someroadstable;
</programlisting>
<informaltable>
<tgroup cols="2">
<tbody>
<row>
<entry><para><informalfigure>
<mediaobject>
<imageobject>
<imagedata fileref="images/st_offsetcurve01.png" />
</imageobject>
<caption><para>15, 'quad_segs=4 join=round' original line and its offset 15 units to the left.</para></caption>
</mediaobject>
</informalfigure>
<programlisting>
SELECT ST_AsText(ST_OffsetCurve(ST_GeomFromText(
'LINESTRING (154 6, 134 6, 114 6, 94 6, 74 6, 54 6, 34 6, 14 6, 10 6,
8 6, 7 7, 6 8, 6 10, 6 30, 6 50, 6 70, 6 90, 6 110, 6 130, 6 150, 6 170, 6 185)'), 15, 'quad_segs=4 join=round'));
--output --
LINESTRING(154 -9,8 -9,2.25974851452365 -7.8581929876693,
-2.60660171779821 -4.60660171779821,-4.60660171779821 -2.60660171779821,
-7.85819298766932 2.2597485145237,-9 8,-9 185)
</programlisting>
</para></entry>
<entry><para><informalfigure>
<mediaobject>
<imageobject>
<imagedata fileref="images/st_offsetcurve02.png" />
</imageobject>
<caption><para>-15, 'quad_segs=4 join=round' original line and its offset 15 units to the right.</para></caption>
</mediaobject>
</informalfigure>
<programlisting>
SELECT ST_AsText(ST_OffsetCurve(ST_GeomFromText(
'LINESTRING (154 6, 134 6, 114 6, 94 6, 74 6, 54 6, 34 6, 14 6, 10 6,
8 6, 7 7, 6 8, 6 10, 6 30, 6 50, 6 70, 6 90, 6 110, 6 130, 6 150, 6 170, 6 185)'), -15, 'quad_segs=4 join=round'));
-- output --
LINESTRING(21 185,21 21,154 21);
</programlisting>
</para></entry>
</row>
<row>
<entry><para><informalfigure>
<mediaobject>
<imageobject>
<imagedata fileref="images/st_offsetcurve03.png" />
</imageobject>
<caption><para>15, 'quad_segs=4 join=bevel' showm with original line</para></caption>
</mediaobject>
</informalfigure>
<programlisting>
SELECT ST_AsText(ST_OffsetCurve(ST_GeomFromText(
'LINESTRING (154 6, 134 6, 114 6, 94 6, 74 6, 54 6, 34 6, 14 6, 10 6,
8 6, 7 7, 6 8, 6 10, 6 30, 6 50, 6 70, 6 90, 6 110, 6 130, 6 150, 6 170, 6 185)'), 15, 'quad_segs=4 join=bevel'));
-- output --
LINESTRING(154 -9,8 -9,-2.60660171779821 -4.60660171779821,-4.60660171779821 -2.60660171779821,-9 8,-9 185)
</programlisting>
</para></entry>
<entry><para><informalfigure>
<mediaobject>
<imageobject>
<imagedata fileref="images/st_buffer04.png" />
</imageobject>
<caption><para>15,-15 collected, join=mitre mitre_limit=2.1</para></caption>
</mediaobject>
</informalfigure>
<programlisting>
SELECT ST_AsText(ST_Collect(
ST_OffsetCurve(geom, 15, 'quad_segs=4 join=mitre mitre_limit=2.2'),
ST_OffsetCurve(geom, -15, 'quad_segs=4 join=mitre mitre_limit=2.2')
) )
FROM ST_GeomFromText(
'LINESTRING (154 6, 134 6, 114 6, 94 6, 74 6, 54 6, 34 6, 14 6, 10 6,
8 6, 7 7, 6 8, 6 10, 6 30, 6 50, 6 70, 6 90, 6 110, 6 130, 6 150, 6 170, 6 185)') As geom;
-- output --
MULTILINESTRING((154 -9,1.78679656440358 -9,-9 1.78679656440358,-9 185),(21 185,21 21,154 21))
</programlisting>
</para></entry>
</row>
</tbody>
</tgroup>
</informaltable>
</refsection>
<refsection>