15 #ifndef QGSSINGLESYMBOLRENDERERV2WIDGET_H    16 #define QGSSINGLESYMBOLRENDERERV2WIDGET_H    50     void changeSingleSymbol();
    52     void sizeScaleFieldChanged( 
const QString& fldName );
    55     void showSymbolLevels();
    65 #endif // QGSSINGLESYMBOLRENDERERV2WIDGET_H 
Map canvas is a class for displaying all GIS data types on a canvas. 
 
Represents a vector layer which manages a vector based data sets.