QGIS QgsFeature未按特定比例显示

问题描述

下面的代码是从多个点创建方位线。问题在于此行仅在我以较大比例放大时显示，通常此行不显示。函数algo-> getDFlist（）返回方位点列表。谁能向我解释问题所在？

        QgsVectorLayer* bearingLayer = new QgsVectorLayer("LineString","Bearing","memory");
        QgsStringMap properties;
        properties.insert("color","red");
        properties.insert("size","2");
        QgsLineSymbol* symbol = QgsLineSymbol::createSimple(properties);
        QgsSingleSymbolRenderer* render = new QgsSingleSymbolRenderer(symbol);
        bearingLayer->setRenderer(render);

        QgsVectorDataProvider* bearing_provider = bearingLayer->dataProvider();
        QgsFeature* bearing_feature = new QgsFeature;       
        BearingAlgorithm* algo = new BearingAlgorithm;
        QList list = algo->getDFlist(105,21,30);
        QgsPolyline* lines = new QgsPolyline(list.count());
        for (size_t i = 0; i append(QgsPoint(list[i].Longitude,list[i].Latitude));
        }
        bearing_feature->setGeometry(QgsGeometry::fromPolyline(*lines));

        bearing_provider->addFeature(*bearing_feature);
        bearingLayer->updateExtents();
        bearingLayer->setScaleBasedVisibility(false);

解决方法

暂无找到可以解决该程序问题的有效方法，小编努力寻找整理中！

如果你已经找到好的解决方法，欢迎将解决方案带上本链接一起发送给小编。

小编邮箱:dio#foxmail.com (将#修改为@）