[Qgis-developer] Re: [Qgis-user] Announcing Qgis-mapper project

[Tim Sutton]

Hi

On Mon, 2008-11-17 at 22:24 +0100, Martin Dobias wrote:
> On Mon, Nov 17, 2008 at 8:30 PM, Tim Sutton <tim at linfiniti.com> wrote:
> > Me too! If you are developing in your own, what are your plans in terms
> > of integration into QGIS trunk? I guess you need to modify core to some
> > degree and then plan to put the rest of functionality out into python
> > plugin space? I would welcome better renderer implementation (ideally
> > that supports SLD spec).
> 
> We'd like to integrate as much as possible directly into QGIS trunk.
> There will be quite some changes for core library. As there should be
> stable API for 1.x releases, we will have to integrate new features
> with care. Some things will be maybe shifted to 2.0 release if it
> won't be possible to integrate them to 1.x branch.
> 
> Briefly what's planned for new renderer implementation:
> - multi-layer symbols (the greatest change)
> - more symbol layer types - e.g. simple line, marker line ...
> - rendering with special order (to allow drawing good-looking roads
> with outline)
> - rendering is done directly in renderer, not in vector layer
> - catalog of symbology
> 
> I don't know whether it will be "compatible" with SLD specification,
> I'm not very familiar with it... How far from SLD is QGIS now?

Well it sounds like your proposed changes would bring us closer to SLD
spec with regards to vector anyway. SLD allows to specify cap style for
lines, and also allows more than one line symbolizer per layer object.
This means that by doing:

                    <sld:LineSymbolizer>
                        <sld:Stroke>
                            <sld:CssParameter name="stroke">
                                <ogc:Literal>#FF0000</ogc:Literal>
                            </sld:CssParameter>
                            <sld:CssParameter name="stroke-linecap">
                                <ogc:Literal>butt</ogc:Literal>
                            </sld:CssParameter>
                            <sld:CssParameter name="stroke-linejoin">
                                <ogc:Literal>miter</ogc:Literal>
                            </sld:CssParameter>
                            <sld:CssParameter name="stroke-opacity">
                                <ogc:Literal>1.0</ogc:Literal>
                            </sld:CssParameter>
                            <sld:CssParameter name="stroke-width">
                                <ogc:Literal>5.0</ogc:Literal>
                            </sld:CssParameter>
                            <sld:CssParameter name="stroke-dashoffset">
                                <ogc:Literal>0.0</ogc:Literal>
                            </sld:CssParameter>
                        </sld:Stroke>
                    </sld:LineSymbolizer>
                    <sld:LineSymbolizer>
                        <sld:Stroke>
                            <sld:CssParameter name="stroke">
                                <ogc:Literal>#00FF00</ogc:Literal>
                            </sld:CssParameter>
                            <sld:CssParameter name="stroke-linecap">
                                <ogc:Literal>butt</ogc:Literal>
                            </sld:CssParameter>
                            <sld:CssParameter name="stroke-linejoin">
                                <ogc:Literal>miter</ogc:Literal>
                            </sld:CssParameter>
                            <sld:CssParameter name="stroke-opacity">
                                <ogc:Literal>0.6</ogc:Literal>
                            </sld:CssParameter>
                            <sld:CssParameter name="stroke-width">
                                <ogc:Literal>20.0</ogc:Literal>
                            </sld:CssParameter>
                            <sld:CssParameter name="stroke-dashoffset">
                                <ogc:Literal>0.0</ogc:Literal>
                            </sld:CssParameter>
                        </sld:Stroke>
                    </sld:LineSymbolizer>


You can get something like the attached image. In an ideal world we
should move our QGIS project files to use SLD representations instead of
QGIS's on devised system. I see some issues with this though as we have
things like actions that afaik cant be represented in SLD. As a
compromise it would be nice to be able to use save as... to save out sld
so that the sld can be used with mapserver / geoserver. Equally it would
be nice to be able to load symbology for a vector from an sld xml file
and have all the features therin supported.

Something to bear in mind anyway since it sounds like your goals might
converge well with supporting SLD.

Regards

Tim



> 
> Martin

-- 
Tim Sutton - QGIS Project Steering Committee Member (Release  Manager)
==============================================
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Skype: timlinux Irc: timlinux on #qgis at freenode.net
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