[Qgis-developer] Displaying map with QgsUniqueValueRenderer

[satya satya]

Thank you very much Marco.
Now i am able to display features.
regards,
satya

On 3/7/07, Marco Hugentobler <marco.hugentobler at karto.baug.ethz.ch> wrote:
>
> Hi Satya,
>
> Is "Dmg_zip" an attribute name or an attribute value?
> You need to specify the attribute _value_ for which you want the symbol to
> apply. Additionally, you need to give the classification field index to
> the
> renderer, so that it knows in which attribute to look.
>
> You can see how the QGIS application itself does it. Look at the unique
> value
> dialog class QgsUniqueValueDialog.cpp/h.
>
> All the best,
> Marco
>
> Am Mittwoch, 7. März 2007 17:17 schrieb satya satya:
> > Hi Marco,
> > I uncommented //mypRenderer->insertValue("point",symbol); , I changed
> > "POINT" to "Dmg_zip" which is one of the attributes of my shape file.
> > Unfortunately it displayed nothing. Do i need to iterate all the points
> in
> > the shaped file??
> > Thaking you
> > regards
> > satya
> >
> > On 3/7/07, Marco Hugentobler <marco.hugentobler at karto.baug.ethz.ch>
> wrote:
> > > Hi Satya,
> > >
> > > Just use the Method QgsUniqueValueRenderer::insertValue(QString name,
> > > QgsSymbol* symbol). The first parameter is the attribute value for
> which
> > > the
> > > symbol is valid, the second a pointer to your symbol (ok, 'name' is a
> > > misleading name for the parameter...)
> > >
> > > In the code below, there is the outcommented line
> > > //mypRenderer->insertValue("point",symbol);
> > > I suppose "point" is not the attribute value for which you want the
> > > symbol to
> > > be applied? Try to replace it with the attribute value and see if it
> > > works.
> > >
> > > If you want the symbol to be valid for all features, then you can use
> > > QgsSingleSymbolRenderer, method
> > > QgsSingleSymbolRenderer::addSymbol(QgsSymbol*)
> > >
> > > Best regards,
> > > Marco
> > >
> > > Am Mittwoch, 7. März 2007 15:38 schrieb satya satya:
> > > > Hi tim,
> > > > Here is the code
> > > >
> > > > // QGIS Includes
> > > > // Qt Includes
> > > > // Std Includes
> > > >
> > > > int main(int argc, char ** argv)
> > > > {
> > > >   // Start the Application
> > > >   QgsApplication app(argc, argv, true);
> > > >
> > > >   QString myPluginsDir        = "...../lib/qgis";
> > > >   QString myLayerPath1         = ".............................
> > > > .......shp"; QString myLayerBaseName1     =
> "....................shp";
> > > >   QString myProviderName      = "ogr";
> > > >   QgsSymbol* symbol;
> > > >   QColor* color;
> > > >
> > > >
> > > >     color = new QColor(255,0,0,255);
> > > >
> > > >         symbol = new QgsSymbol(color->rgb());
> > > >
> > > >   // Instantiate Provider Registry
> > > >   QgsProviderRegistry::instance(myPluginsDir);
> > > >   QgsVectorLayer * mypLayer = new QgsVectorLayer(myLayerPath1,
> > > > myLayerBaseName1, myProviderName);
> > > >
> > > >    //get the field list associated with the layer
> > > > std::vector<QgsField> myFields=mypLayer->fields();
> > > >   QgsUniqueValueRenderer *mypRenderer=new
> > > > QgsUniqueValueRenderer(mypLayer->vectorType());
> > > >
> > > >   mypRenderer->setClassificationField(5);
> > > >
> > > > symbol->setColor(Qt::red);
> > > >   symbol->setFillColor(QColor(255,0,0));
> > > >   symbol->setLabel("HELLO");
> > > >   symbol->setPointSize (5);
> > > >
> > > >
> > > >   std::deque<QString> myLayerSet;
> > > >   mypLayer->setRenderer(mypRenderer);
> > > > //mypRenderer->insertValue("point",symbol);
> > > > if (mypLayer->isValid())
> > > >   {
> > > >     qDebug("Layer is valid");
> > > >   }
> > > >   else
> > > >   {
> > > >     qDebug("Layer is NOT valid");
> > > >   }
> > > >
> > > >   // Add the Vector Layer to the Layer Registry
> > > >
> > > >   QgsMapLayerRegistry::instance()->addMapLayer(mypLayer, TRUE);
> > > >     // Add the Layer to the Layer Set
> > > >
> > > >
> > > >
> > > >   myLayerSet.push_back(mypLayer->getLayerID());
> > > >   mypLayer->setVisible(TRUE);
> > > >
> > > >
> > > >
> > > >   // Create the Map Canvas
> > > >   QgsMapCanvas * mypMapCanvas = new QgsMapCanvas(0, 0);
> > > >   mypMapCanvas->setExtent(mypLayer->extent());
> > > >   // cbit qDebug(mypMapCanvas->extent().stringRep(2));
> > > >
> > > >   mypMapCanvas->enableAntiAliasing(true);
> > > >   mypMapCanvas->setCanvasColor(QColor(255, 255, 255));
> > > >   mypMapCanvas->freeze(false);
> > > >   // Set the Map Canvas Layer Set
> > > >   mypMapCanvas->setLayerSet(myLayerSet);
> > > >   mypMapCanvas->setVisible(true);
> > > >   mypMapCanvas->refresh();
> > > >  // Start the Application Event Loop
> > > > //cout<<marker_symbol->picture().toStdString()<<endl;
> > > > app.exec();
> > > >  //QgsMapCanvas myMapCanvas(0, 0);
> > > >  QgsMapLayerRegistry::instance()->removeAllMapLayers();
> > > > return 0;
> > > > }
> > > >
> > > > I created symbol, but don't know how to add that to the unique value
> > > > renderer.
> > > >
> > > > Thanking you
> > > > cheers
> > > > satya
> > > >
> > > > > On 3/5/07, Tim Sutton <tim at linfiniti.com> wrote:
> > > > > > Hi
> > > > > >
> > > > > > How about posting code examples of what you have tried and we
> can
> > >
> > > try
> > >
> > > > > > to help you from there....
> > > > > >
> > > > > > Regards
> > > > > >
> > > > > > Tim
> > > > > >
> > > > > > 2007/3/5, satya satya <satya341 at gmail.com >:
> > > > > > > Hello all,
> > > > > > >               I am trying to develop a simple application
> using
> > >
> > > QGis
> > >
> > > > > > API.
> > > > > >
> > > > > > >  I have read all tutorials on QGis blog. I would like to use
> > > > > > > "QgsUniqueValueRenderer" in my application to display features
> in
> > > > > > > diff
> > > > > > >
> > > > > > > colors. I tried that  "QgsUniqueValueRenderer" , but no luck.
> > > > > > >  could some body help me .
> > > > > > >  cheers
> > > > > > >  satya
> > > > > > >
> > > > > > > _______________________________________________
> > > > > > > Qgis-developer mailing list
> > > > > > > Qgis-developer at lists.qgis.org
> > > > > > > http://lists.qgis.org/cgi-bin/mailman/listinfo/qgis-developer
> > > > > >
> > > > > > --
> > > > > > --
> > > > > > Tim Sutton
> > > > > >
> > > > > > Visit http://qgis.org for a great Open Source GIS
> > > > > > Home Page: http://linfiniti.com
> > > > > > Skype: timlinux
> > > > > > MSN: tim_bdworld at msn.com
> > > > > > Yahoo: tim_bdworld at yahoo.com
> > > > > > Jabber: timlinux
> > > > > > Irc: timlinux on #qgis at freenode.net
>
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