This algorithm is no longer required - it's been replaced by
the 'Promote to multipart' and 'Collect geometries" algorithms.
Tagged as feature to remember to include in release notes
This is basically the equivalent of the dissolve algorithm, but
instead of a dissolving overlapping geometries the geometries
are instead just collected together into a multipart geometry.
It's designed to slot between the 'promote to multipart' algorithm
(which performs no collection of geometries - it just converts
singleparts to multiparts with 1 part) and the more complex
all-encompassing 'aggregate' algorithm.
This algorithm is basically the equivalent of the ST_Multi(...)
command - it forces a feature's geometry to become multipart,
regardless of the input geometry type.
If input geometries are singlepart, they will output as
multipart with just 1 part. If they are already multipart,
they will be output unchanged.
Tagged as feature to be included in release notes.
Because:
- The use case for this algorithm is very unclear for users - the name
does not describe what the algorithm does, and there's no help
documentation available for the algorithm either. Given this I suspect
that the algorithm is not being put into use.
- The algorithm needs enhancement to be more useful. There's no logic
in place which dictates how neighbouring features are chosen to
dissolve into the selected feature (it's effectively random - you're
just as likely to get a huge narrow polygon stretching across a map as
you are a nice compact cluster). To be more useful the algorithm would
need logic to either minimise the area of the dissolved feature, or
minimise the total number of dissolved features, or ... ?
Now that the extra features of the "polygon from vector layer extent"
algorithm are covered by the new "Minimum bounding geometry" algorithm,
we can replace the previous two "polygon from vector extent" and
"polygon from raster extent" algorithms by a single "polygon
from layer extent" algorithm.
feature based algorithms
Instead of algorithms which handle both whole layers/groups
of features/individual features, we leave the whole layer
and group of features handling to the "Minimum bounding
geometry" algorithm.
The feature-by-feature algorithms are now native c++
algorithms.
This affects:
- bounding boxes
- convex hulls
- minimum enclosing circle
- minimum oriented rectangles
This algorithm creates geometries which enclose the features
from an input layer.
Numerous enclosing geometry types are supported, including
bounding boxes (envelopes), oriented rectangles, circles and
convex hulls.
Optionally, the features can be grouped by a field. If set,
this causes the output layer to contain one feature per grouped
value with a minimal geometry covering just the features with
matching values.
Instead move it to a private QgsGeometry member. It's copied
with QgsGeometry, but not the underlying private geometry
data.
This means the error string can be changed without detaching
(and copying) the geometry data.
Also make greater use of error string for all use of GEOS
functions.
Instead of just forcing writing the triangulation to a shapefile (boo!)
change the parameter to use a QgsFeatureSink, so that anything
which implements the QgsFeatureSink interface can be used for
storing the triangulation.
These classes still need a lot of cleanup (e.g. use of proper
3d geometry classes instead of their own 3d line classes, etc)
and we don't want them locked into the 3.0 API.
Better to remove them from the API and reintroduce them after
they have been cleaned up (in >3.0). They are mostly implementation
details anyway, and unlikely to be used outside of the high
level interpolation classes.
We don't want these part of stable API - this namespace really shouldn't
exist, as it mostly contains code which is duplicated in other
parts of the API (with better maintained and tested versions).
This is the equivalent of std::as_const (which requires c++17) or
qAsConst (which requires Qt 5.7), neither of which we have
as minimum dependancies.
By wrapping implicitly shared Qt containers in qgsAsConst we can
safely use c++ for ranged loops instead of Q_FOREACH. (Since
Q_FOREACH's future is shaky)
See https://www.kdab.com/goodbye-q_foreach/ for further details
on why for causes a detach for Qt containers and why Q_FOREACH
is being removed from Qt.
