This algorithm joins all connected parts of MultiLineString
geometries into single LineString geometries.
If any parts of the input MultiLineString geometries are not
connected, the resultant geometry will be a MultiLineString
containing any lines which could be merged and any non-connected
line parts.
All pointer based methods have been removed.
Now we have only:
void setGeometry( const QgsGeometry& geom )
and
QgsGeometry geometry() const
Benefits include avoiding a whole lot of tricky pointer lifetime
issues, potential memory leaks, and finally closing #777, which
has survived for over 9 years!...
Impacts on PyQGIS code:
- no more need for the messy
g = QgsGeometry( feature.geometry() )
workaround, just use g = feature.geometry() instead
- IMPORTANT: you can no longer test whether a feature has geometry
using `if f.geometry():`, since QgsFeature::geometry() will
*always* return an object. Instead, use
`if not f.geometry().isEmpty():`, or preferably the new method
`if not f.hasGeometry():`
Fix#777
Adds a new method to QgsGeometry for merging linestrings.
By passing a multilinestring, any connected lines will
be joined into single linestrings. Behind the scenes this
uses GEOS' line merge.
A corresponding expression function "line_merge" has also
been added.
Returns the closure of the combinatorial boundary of the
geometry (ie the topological boundary of the geometry).
For instance, a polygon geometry will have a boundary
consisting of the linestrings for each ring in the polygon.
Follows OGC / SQL/MM specs for boundary calculation
...and leave only:
QgsCoordinateTransform( const QgsCoordinateReferenceSystem& source,
const QgsCoordinateReferenceSystem& destination );
The other constructors were not used anyway in QGIS code,
had awkward/confusing API, and no unit tests.
And rename to QgsUnitTypes::RenderUnits. This enum is used in
much more contexts than just symbols, so QgsUnitTypes is a
better fit for it.
All methods which previously accepted QgsSymbolV2::OutputUnit
parameters or QgsSymbolV2::OutputUnitList parameters now take
QgsUnitTypes::RenderUnit or QgsUnitTypes::RenderUnitList
parameters respectively.
This change consolidates more unit handling and conversion into
QgsUnitTypes.
Additionally, UnknownUnit was renamed to UnknownDistanceUnit.
All methods which accepted QGis::UnitType parameters have been
updated to take QgsUnitTypes::DistanceUnit instead.
ALso remove the unit handling methods toLiteral, fromLiteral, tr,
fromTr, and fromUnitToUnitFactor from QGis. Their corresponding
counterparts in QgsUnitTypes should be used instead.
