[Qgis-developer] Editing the geometry of a feature

[Tait, Roger]

Hi,



I have a QGis::WKBPoint based vector layer containing a single feature.

I want to change the position of the feature using a single click of a button embedded in the tool bar.

I have unsuccessfully tried to change the position using the following:





void QgisApp::trackWayPoint()

{



   ...

   ...



   QgsFeature *feature = pointLayer->getFirstFeature(true,false);

   QgsGeometry *geometry = feature->geometry();



   unsigned char *wkb = geometry->wkbBuffer();



   memcpy(&wkb[5], &newPosX, sizeof(double));

   memcpy(&wkb[5]+sizeof(double), &newPosY, sizeof(double));



}







The correct feature and geometry are referenced however for some reason the new position is lost before the feature is drawn to screen.

I have also tried commitAttributeChanges(const std::set<QString>& deleted, ... ,std::map<QString,QString> >& changed); without success.



Please tell me how I can change the position of a feature?



Thanks Roger

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