[Qgis-developer] Improve symbology system

[Nathan Woodrow]

Try this one https://dl.dropbox.com/u/6170988/layers.png

- Nathan

On Fri, Sep 28, 2012 at 3:20 PM, Denis Rykov <rykovd at gmail.com> wrote:
>
> Thanks, but when I try to open Image I get - HTTP 403 (Forbidden)
>
> On Fri, Sep 28, 2012 at 12:16 PM, Nathan Woodrow <madmanwoo at gmail.com>
> wrote:
>>
>> I can get QGIS to do what you need:
>>
>> http://img6.imagebanana.com/img/uewfzlmc/Workspace1_155.png
>>
>> Selected the Symbol:Fill tree item and then selected Advanced->Symbol
>> Levels
>>
>> Just enable symbols levels and it will render how you need.
>>
>> - Nathan
>>
>> On Fri, Sep 28, 2012 at 2:35 PM, Denis Rykov <rykovd at gmail.com> wrote:
>> > QGIS is used rendering order of symbol layers within features not within
>> > layer. Try to set up layer (two overlapped polygons) symbology for
>> > getting
>> > such result http://hub.qgis.org/attachments/4909/geoserver_sld.png. Of
>> > course you can open the same layer twice and set up their symbology
>> > separately, but it is not the right solution.
>> >
>> >
>> > On Fri, Sep 28, 2012 at 11:18 AM, Nathan Woodrow <madmanwoo at gmail.com>
>> > wrote:
>> >>
>> >> QGIS does already have the ability to control the rendering order of
>> >> symbol layers, and should be able to do what you need.
>> >>
>> >> - Nathan
>> >>
>> >> Sent from some fancy phone looking thingo
>> >> ________________________________
>> >> From: Denis Rykov
>> >> Sent: 28/09/2012 1:29 PM
>> >> To: qgis-developer at lists.osgeo.org
>> >> Subject: [Qgis-developer] Improve symbology system
>> >>
>> >> Some days ago I've faced with the following problem. For example, I
>> >> have
>> >> two overlapped polygons and want to draw this layer such way:
>> >> http://hub.qgis.org/attachments/4909/geoserver_sld.png Now it looks
>> >> like I
>> >> cannot do it with QGIS symbology system. Screenshot which I provided
>> >> above
>> >> was made in GeoServer with the following SLD configuration:
>> >>
>> >>> <StyledLayerDescriptor version="1.0.0"
>> >>> xmlns:xlink="http://www.w3.org/1999/xlink"
>> >>> xmlns:ogc="http://www.opengis.net/ogc"
>> >>> xmlns="http://www.opengis.net/sld">
>> >>> <NamedLayer>
>> >>> <Name>test</Name>
>> >>> <UserStyle>
>> >>> <Name>test</Name>
>> >>> <FeatureTypeStyle>
>> >>> <Rule>
>> >>> <LineSymbolizer>
>> >>> <Stroke>
>> >>> <CssParameter name="stroke-width">4</CssParameter>
>> >>> <CssParameter name="stroke">#dddddd</CssParameter>
>> >>> </Stroke>
>> >>> </LineSymbolizer>
>> >>> </Rule>
>> >>> </FeatureTypeStyle>
>> >>> <FeatureTypeStyle>
>> >>> <Rule>
>> >>> <PolygonSymbolizer>
>> >>> <Fill>
>> >>> <CssParameter name="fill">#fa5000</CssParameter>
>> >>> </Fill>
>> >>> </PolygonSymbolizer>
>> >>> </Rule>
>> >>> </FeatureTypeStyle>
>> >>> </UserStyle>
>> >>> </NamedLayer>
>> >>> </StyledLayerDescriptor>
>> >>
>> >>
>> >> I tried to import this SLD into QGIS, but SLD docs containing multiple
>> >> FeatureTypeStyle are not supported yet (#6413). But I think that
>> >> problem is
>> >> more seriously. Now in QGIS rendering performs by features but not by
>> >> layers. Try to explain it. For example we have two symbol's layer -
>> >> first
>> >> with border, but without filling and second - with filling but without
>> >> border. If we try to render such layer we will get the following
>> >> result:
>> >> http://gis-lab.info/forum/download/file.php?id=5008. It is expected
>> >> beacause QGIS is used by feature rendering approach. Another approach
>> >> is
>> >> using rendering by layer: first draw a layer according to the symbology
>> >> of
>> >> the first level, and then second and then overlying each other. In this
>> >> case
>> >> we get result as in GeoServer. I think that this approach is more
>> >> flexible,
>> >> using "by layer" rendering we can get the the same result as using "by
>> >> feature" approach (in our case using one level symbology with border
>> >> and
>> >> filling). Is it to makes sense to add checkbox to each symbology layer
>> >> wich
>> >> will be indicate QGIS rendering system used "by layer" rendering
>> >> approach?
>> >>
>> >> ArcGIS is used "by feature" approach but solves described issue by
>> >> using
>> >> join operator, for example:
>> >> http://gis-lab.info/share/DR/screenshots/symbollevels.png
>> >
>> >
>
>