Contents
How is a vector layer selected in QGIS?
Takes a vector layer and generates a new one that contains only a subset of the features in the input layer. The subset is defined randomly, using a percentage or count value to define the total number of features in the subset. The percentage/count value is not applied to the whole layer, but instead to each category.
How is a subset defined in Vector selection?
Takes a vector layer and generates a new one that contains only a subset of the features in the input layer. The subset is defined randomly, based on feature IDs, using a percentage or count value to define the total number of features in the subset.
What are the criteria for selecting features in QGIS?
The criteria for selecting features is based on a QGIS expression. Creates a selection in a vector layer. The criteria for selecting features is based on the spatial relationship between each feature and the features in an additional layer. Condition for the selection. Array of one or more of the following predicates:
How are features selected in a vector layer?
Creates a selection in a vector layer. The criteria for selecting features is based on a QGIS expression. Creates a selection in a vector layer. The criteria for selecting features is based on the spatial relationship between each feature and the features in an additional layer. Condition for the selection.
How can I change the properties of a vector layer?
The Layer Properties dialog for a vector layer provides information about the layer, symbology settings and labeling options. If your vector layer has been loaded from a PostgreSQL/PostGIS datastore, you can also alter the underlying SQL for the layer by invoking the Query Builder dialog on the General tab.
How does QGIS load a layer from the database?
When loading a layer from the database, if a style already exists for this layer, QGIS will load the layer and its style. You can add several style in the database. Only one will be the default style anyway.
How to retrieve layer from qgsprocessingparameters-QGIS?
The destinationIdentifier argument will be set to a string which can be used to retrieve the layer corresponding to the sink, e.g. via calling QgsProcessingUtils.mapLayerFromString () This function creates a new object and the caller takes responsibility for deleting the returned object.
What do you call the output field in QGIS?
An Output filename expression textbox that is used to generate a filename for each geometry if needed. It is based on expressions. This field is meaningful only for rendering to multiple files.