[Qgis-developer] Displaying map with QgsUniqueValueRenderer
satya satya
satya341 at gmail.com
Wed Mar 14 13:03:55 EDT 2007
Hello,
I am able to display features using unique value renderer now :).
Could you please tell me how to give different "symbols" to different
attributes in a particular field.
Here is the code with which i am trying to display features:
mypRenderer->setClassificationField (2);
//std::list<int> attributes=mypRenderer->classificationAttributes();
mypRenderer->insertValue ("1st attribute",symbol);
mypRenderer->insertValue ("2dn attribute",symbol1);
Here i am hardcoding to give different colors for diferent attributes.
Is there any way do to it in a generic way.
Thanking you
cheers
satya
On 3/7/07, satya satya <satya341 at gmail.com> wrote:
>
> 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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