<html><body><div style="color:#000; background-color:#fff; font-family:arial, helvetica, sans-serif;font-size:10pt"><div><span>Thanks for that...shame it didnīt work.</span></div><div><span><br></span></div><div><span>I have already looked at negative buffers, but they create a polygon within a polygon and not a hole within a "negative-buffered" polyon. i.e my polygon needs to be transparent in the center past the negative buffer so underlying features can be seen.</span></div><div><span><br></span></div><div><span>Andrea Aime thought it could be done with the "Difference" SLD filter, but I canīt seem to get it to work due to my lack of understanding of how the filter works. </span></div><div><span><br></span></div><div><span><a
href="http://docs.geoserver.org/latest/en/user/styling/sld-reference/filters.html">http://docs.geoserver.org/latest/en/user/styling/sld-reference/filters.html</a> <br></span></div><div><span><br></span></div><div><span>yours,</span></div><div><span><br></span></div><div><span>Rob</span></div><div><span><br></span></div><div><span><br></span></div><div><span><br></span></div><div><span><br></span></div><div><br></div> <div style="font-size: 10pt; font-family: arial, helvetica, sans-serif; "> <div style="font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; "> <div dir="ltr"> <font size="2" face="Arial"> <hr size="1"> <b><span style="font-weight:bold;">Von:</span></b> Paul Ramsey <pramsey@opengeo.org><br> <b><span style="font-weight: bold;">An:</span></b> Robert Buckley <robertdbuckley@yahoo.com>; PostGIS Users Discussion <postgis-users@postgis.refractions.net> <br> <b><span style="font-weight:
bold;">Gesendet:</span></b> 22:33 Dienstag, 28.Februar 2012<br> <b><span style="font-weight: bold;">Betreff:</span></b> Re: [postgis-users] how to create a hole in a polygon table?<br> </font> </div> <br>I was thinking of something like this, but it doesn't work.<br>Unfortunately Geoserver doesn't have the ability to create offset<br>lines, so there's no nice way to do this without doing a little<br>negative buffer on the shape (which incidentally, you could do using<br>the geometry transformation facility on the fly<br><a href="http://docs.geoserver.org/stable/en/user/styling/sld-extensions/geometry-transformations.html" target="_blank">http://docs.geoserver.org/stable/en/user/styling/sld-extensions/geometry-transformations.html</a><br><br>P<br><br><?xml version="1.0" encoding="ISO-8859-1"?><br><StyledLayerDescriptor version="1.0.0"<br>xmlns="<a href="http://www.opengis.net/sld" target="_blank">http://www.opengis.net/sld</a>"<br>xmlns:ogc="<a
href="http://www.opengis.net/ogc" target="_blank">http://www.opengis.net/ogc</a>"<br> xmlns:xlink="<a href="http://www.w3.org/1999/xlink" target="_blank">http://www.w3.org/1999/xlink</a>"<br>xmlns:xsi="<a href="http://www.w3.org/2001/XMLSchema-instance" target="_blank">http://www.w3.org/2001/XMLSchema-instance</a>"<br>xmlns:gml="<a href="http://www.opengis.net/gml" target="_blank">http://www.opengis.net/gml</a>"<br> xsi:schemaLocation="<a href="http://www.opengis.net/sld" target="_blank">http://www.opengis.net/sld</a><br><a href="http://schemas.opengis.net/sld/1.0.0/StyledLayerDescriptor.xsd" target="_blank">http://schemas.opengis.net/sld/1.0.0/StyledLayerDescriptor.xsd</a>"><br> <NamedLayer><br> <Name>USA states</Name><br> <UserStyle> <Name>population</Name><br> <Title>United States</Title><br>
<Abstract>A Simple Brush Style</Abstract><br> <FeatureTypeStyle><br> <Rule><br> <LineSymbolizer><br> <Stroke><br> <GraphicStroke><br> <Graphic><br> <ExternalGraphic><br> <OnlineResource xlink:type="simple"<br>xlink:href="file:///Users/pramsey/green_bottom.gif" /><br> <Format>image/gif</Format><br> </ExternalGraphic><br> </Graphic><br> </GraphicStroke><br> <CssParameter name="stroke-linecap">round</CssParameter><br>
<CssParameter name="stroke-dasharray">1 0 1 0</CssParameter><br> </Stroke><br> </LineSymbolizer><br> </Rule><br> </FeatureTypeStyle><br> </UserStyle><br> </NamedLayer><br></StyledLayerDescriptor><br><br><br>On Tue, Feb 28, 2012 at 12:00 PM, Robert Buckley<br><<a ymailto="mailto:robertdbuckley@yahoo.com" href="mailto:robertdbuckley@yahoo.com">robertdbuckley@yahoo.com</a>> wrote:<br>> Thanks for the advice.<br>><br>> Unfortunately I donīt understand what you have just told me....half-brush?<br>> half-circle?<br>><br>> are these sld specifications?...I am delivering wms data using sldīs to<br>> style the data.<br>><br>> could you please clarify?<br>><br>> cheers,<br>><br>> Rob<br>><br>> ________________________________<br>> Von: Paul Ramsey <<a
ymailto="mailto:pramsey@opengeo.org" href="mailto:pramsey@opengeo.org">pramsey@opengeo.org</a>><br>> An: Robert Buckley <<a ymailto="mailto:robertdbuckley@yahoo.com" href="mailto:robertdbuckley@yahoo.com">robertdbuckley@yahoo.com</a>>; PostGIS Users Discussion<br>> <<a ymailto="mailto:postgis-users@postgis.refractions.net" href="mailto:postgis-users@postgis.refractions.net">postgis-users@postgis.refractions.net</a>><br>> Gesendet: 19:20 Dienstag, 28.Februar 2012<br>> Betreff: Re: [postgis-users] how to create a hole in a polygon table?<br>><br>> Rather than geometry processing, work on your rendering engine. You<br>> can usually achieve an interior band (the classic National Geographic<br>> political boundary, yes?) with a half-brush (rather than a full<br>> circle, use a half-circle), and just ensuring your polygons are<br>> consistently oriented.<br>><br>> P.<br>><br>> On Tue, Feb 28, 2012 at
10:04 AM, Robert Buckley<br>> <<a ymailto="mailto:robertdbuckley@yahoo.com" href="mailto:robertdbuckley@yahoo.com">robertdbuckley@yahoo.com</a>> wrote:<br>>> Hi,<br>>><br>>> I am trying to create an inner buffer of a polygon geometry table.<br>>> Unfortunately this is the only way I can think of which will enable me to<br>>> make a certain symbol for a polyon layer. The SLD Filter "difference"<br>>> might<br>>> do it, but it needs to be nested and iīm not sure if this is possible.<br>>><br>>> anyway....My polygons need to be symbolized with a thin outline AND an<br>>> inside Buffer of 3 mm(150m at a scale of 1:50 000)....in essence just an<br>>> inside ring.<br>>><br>>> This means I need to first buffer my polygon geometry and then substract<br>>> the<br>>> buffer from the original polygon. = ST_Difference (i think!?!)<br>>><br>>>
my attempt created some geometries but not what I was expecting...<br>>><br>>> create view rrop08.rrop_01_13_innerbuffer AS<br>>><br>>> SELECT ST_Difference(a.st_buffer, b.the_geom)<br>>><br>>> FROM rrop08.rrop_01_13_buffer a, rrop08.rrop_01_f b;<br>>><br>>><br>>> rrop08.rrop_01_f = the original polyon<br>>><br>>> rrop08.rrop_01_13_buffer = the inner buffer<br>>><br>>><br>>><br>>><br>>><br>>> _______________________________________________<br>>> postgis-users mailing list<br>>> <a ymailto="mailto:postgis-users@postgis.refractions.net" href="mailto:postgis-users@postgis.refractions.net">postgis-users@postgis.refractions.net</a><br>>> <a href="http://postgis.refractions.net/mailman/listinfo/postgis-users"
target="_blank">http://postgis.refractions.net/mailman/listinfo/postgis-users</a><br>>><br>><br>><br>><br>> _______________________________________________<br>> postgis-users mailing list<br>> <a ymailto="mailto:postgis-users@postgis.refractions.net" href="mailto:postgis-users@postgis.refractions.net">postgis-users@postgis.refractions.net</a><br>> <a href="http://postgis.refractions.net/mailman/listinfo/postgis-users" target="_blank">http://postgis.refractions.net/mailman/listinfo/postgis-users</a><br>><br><br><br> </div> </div> </div></body></html>