本文整理汇总了C++中OGRLayer::SetNextByIndex方法的典型用法代码示例。如果您正苦于以下问题：C++ OGRLayer::SetNextByIndex方法的具体用法？C++ OGRLayer::SetNextByIndex怎么用？C++ OGRLayer::SetNextByIndex使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类OGRLayer的用法示例。
在下文中一共展示了OGRLayer::SetNextByIndex方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: switch
boost::optional<mapnik::datasource_geometry_t> ogr_datasource::get_geometry_type() const
{
boost::optional<mapnik::datasource_geometry_t> result;
if (dataset_ && layer_.is_valid())
{
OGRLayer* layer = layer_.layer();
// NOTE: wkbFlatten macro in ogr flattens 2.5d types into base 2d type
#if GDAL_VERSION_NUM < 1800
switch (wkbFlatten(layer->GetLayerDefn()->GetGeomType()))
#else
switch (wkbFlatten(layer->GetGeomType()))
#endif
{
case wkbPoint:
case wkbMultiPoint:
result.reset(mapnik::datasource_geometry_t::Point);
break;
case wkbLinearRing:
case wkbLineString:
case wkbMultiLineString:
result.reset(mapnik::datasource_geometry_t::LineString);
break;
case wkbPolygon:
case wkbMultiPolygon:
result.reset(mapnik::datasource_geometry_t::Polygon);
break;
case wkbGeometryCollection:
result.reset(mapnik::datasource_geometry_t::Collection);
break;
case wkbNone:
case wkbUnknown:
{
// fallback to inspecting first actual geometry
// TODO - csv and shapefile inspect first 4 features
if (dataset_ && layer_.is_valid())
{
layer = layer_.layer();
// only new either reset of setNext
//layer->ResetReading();
layer->SetNextByIndex(0);
OGRFeature *poFeature;
while ((poFeature = layer->GetNextFeature()) != nullptr)
{
OGRGeometry* geom = poFeature->GetGeometryRef();
if (geom && ! geom->IsEmpty())
{
switch (wkbFlatten(geom->getGeometryType()))
{
case wkbPoint:
case wkbMultiPoint:
result.reset(mapnik::datasource_geometry_t::Point);
break;
case wkbLinearRing:
case wkbLineString:
case wkbMultiLineString:
result.reset(mapnik::datasource_geometry_t::LineString);
break;
case wkbPolygon:
case wkbMultiPolygon:
result.reset(mapnik::datasource_geometry_t::Polygon);
break;
case wkbGeometryCollection:
result.reset(mapnik::datasource_geometry_t::Collection);
break;
default:
break;
}
}
OGRFeature::DestroyFeature( poFeature );
break;
}
}
break;
}
default:
break;
}
}
return result;
}