Up to date it was not possible to create a function that handles NULL values with the
@qgsfunction decorator. As soon as any parameter was NULL, the return value would also
be NULL.
Example of a function that returns a value now with a NULL paramter and would have returned NULL before
```
@qgsfunction(args=-1, group='Custom', handlesnull=True)
def mean_value(vals, feature, parent):
valid_vals = [val for val in vals if val != NULL]
return sum(valid_vals)/len(valid_vals)
```
[FEATURE]
Prevents crashes when PyQt4 modules are imported in QGIS 3.x.
This instantly segfaults QGIS. Throwing an exception makes it
easier to identify the cause as a faulty plugin, and shows
exactly where the bad import is located.
Adds a native k-means clustering algorithm.
Based on a port of PostGIS' ST_ClusterKMeans function, this
new algorithm adds a new cluster ID field to a set of input
features identify the feature's cluster based on the k-means
clustering approach. If non-point geometries are used as input,
the clustering is based off the centroid of the input geometries.
bool(obj) in Python has the following semantics:
1. if the object has __bool__() method, return its value
2. if the object has __len__() method, return its value
3. return True
So for objects in QGIS API that implement __len__() method, we were getting
unexpected behavior - for example, "if layer: ..." would evaluate as False
in case the layer was empty, while the usual expectation is that any reference
to an object that is not None should evaluate to True.
- Adding datasets to mesh layer from properties panel
- Information and source panel in properties panel
- Selection of active dataset (properties or styling panel)
- Styling of contours/scalars (properties or styling panel)
- Styling of mesh frame (properties or styling panel)
- Styling of vector arrows (properties or styling panel)
Converts a raster layer into a vector layer, with a polygon feature
corresponding to each pixel from the raster and a single field
containing the band value from the raster.
Sponsored by SMEC/SJ
