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28.1.9. Modellierungswerkzeuge

Warnung

Diese Werkzeuge sind nur in der Grafischen Modellierung verfügbar. Sie sind nicht in der Verarbeitungs-Toolbox verfügbar.

28.1.9.1. Calculate expression

NEW in 3.34

It calculates the result of a QGIS expression and eliminates the need to use the same expression multiple times throughout a model when the same result is required more than once. Additionally, it enables use cases that would otherwise not be possible. For instance, you can generate a timestamp value once and use it multiple times within the model, if the timestamp were recalculated every time, the values would vary during the model’s runtime.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Input

INPUT

[expression]

Expression to calculate

Ausgaben

Bezeichnung

Name

Typ

Beschreibung

Value

OUTPUT

[Result Value]

Calculated result value, the data type of the output will vary based on the specific expression used in the algorithm.

Pythoncode

Algorithm ID: native:calculateexpression

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.2. Bedingte Verzweigung

Fügt einem Modell eine bedingte Verzweigung hinzu, so dass Teile des Modells auf der Grundlage des Ergebnisses eines Ausdrucks ausgeführt werden können. Meistens durch die Verwendung von Werkzeugabhängigkeiten, um den Ablauf des Modells zu steuern.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Field

BRANCH

[string]

Name of the condition

Field

CONDITION

[expression]

Expression to evaluate

Ausgaben

None.

Pythoncode

Algorithm ID: native:condition

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.3. Create directory

Creates a new directory on a file system. Directories will be created recursively, creating all required parent directories in order to construct the full specified directory path. No errors will be raised if the directory already exists.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Directory path

PATH

[string]

Folder path to create

Ausgaben

Bezeichnung

Name

Typ

Beschreibung

Ergebnis

OUTPUT

[folder]

Created folder

Pythoncode

Algorithm ID: native:createdirectory

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.4. Feature filter

Filters features from the input layer and redirects them to one or several outputs. If you do not know about any attribute names that are common to all possible input layers, filtering is only possible on the feature geometry and general record mechanisms, such as $id and uuid.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Input layer

INPUT

[vector: any]

The input layer.

Outputs and filters

(one or more)

OUTPUT_<name of the filter>

[same as input]

The output layers with filters (as many as there are filters).

Ausgaben

Bezeichnung

Name

Typ

Beschreibung

Ergebnis

(one or more)

native:filter_1:OUTPUT_<name of filter>

[same as input]

The output layers with filtered features (as many as there are filters).

Pythoncode

Algorithm ID: native:filter

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.5. Filter layers by type

Filters layers by their type. Incoming layers will be directed to different outputs based on whether they are a vector or raster layer.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Input layer

INPUT

[layer]

Generic Map Layer

Ausgaben

Bezeichnung

Name

Typ

Beschreibung

Vector features

Optional

VECTOR

[vector]

A Vector Layer of the input, if compatible

Raster layer

Optional

RASTER

[raster]

A Raster Layer of the input, if compatible

Pythoncode

Algorithm ID: native:filterlayersbytype

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.6. Load layer into project

Loads a layer to the current project.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Layer

INPUT

[layer]

Layer to load in the legend

Loaded layer name

NAME

[string]

Name of the loaded layer

Ausgaben

Bezeichnung

Name

Typ

Beschreibung

Layer

OUTPUT

[same as input]

The (renamed) loaded layer

Pythoncode

Algorithm ID: native:loadlayer

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.7. Raise exception

Raises an exception and cancels a model’s execution. The exception message can be customized, and optionally an expression based condition can be specified. If an expression condition is used, then the exception will only be raised if the expression result is true. A false result indicates that no exception will be raised, and the model execution can continue uninterrupted.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Message

MESSAGE

[string]

Message to display

Condition

Optional

CONDITION

[expression]

Expression to evaluate if true

Ausgaben

A message in the log panel.

Pythoncode

Algorithm ID: native:raiseexception

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.8. Raise message

Raises an information message in the log. The message can be customized, and optionally an expression based condition can be specified. If an expression condition is used, then the message will only be logged if the expression result is true. A false result indicates that no message will be logged.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Information message

MESSAGE

[string]

Message to display

Condition

Optional

CONDITION

[expression]

Expression to evaluate if true

Ausgaben

A message in the log panel.

Pythoncode

Algorithm ID: native:raisemessage

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.9. Raise warning

Raises a warning message in the log. The warning message can be customized, and optionally an expression based condition can be specified. If an expression condition is used, then the warning will only be logged if the expression result is true. A false result indicates that no warning will be logged.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Message

MESSAGE

[string]

Message to display

Condition

Optional

CONDITION

[expression]

Expression to evaluate if true

Ausgaben

A message in the log panel.

Pythoncode

Algorithm ID: native:raisewarning

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.10. Rename layer

Renames a layer.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Layer

INPUT

[layer]

Layer to rename

New name

NAME

[string]

The new name of the layer

Ausgaben

Bezeichnung

Name

Typ

Beschreibung

Layer

OUTPUT

[same as input]

The (renamed) output layer

Pythoncode

Algorithm ID: native:renamelayer

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.11. Save log to file

Saves the model’s execution log to a file. Optionally, the log can be saved in a HTML formatted version.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Use HTML

USE_HTML

[Boolean]

Default: False

Use HTML formatting

Ausgaben

Bezeichnung

Name

Typ

Beschreibung

File

OUTPUT

[string]

Destination of the log

Pythoncode

Algorithm ID: native:savelog

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.12. Set project variable

Sets an expression variable for the current project.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Variable name

NAME

[string]

Name of the variable

Variable value

VALUE

[string]

Value to be stored

Ausgaben

None.

Pythoncode

Algorithm ID: native:setprojectvariable

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.13. String concatenation

Concatenates two strings into a single one in the Processing Modeler.

Parameter

Bezeichnung

Name

Typ

Beschreibung

Input 1

INPUT_1

[string]

First string

Input 2

INPUT_2

[string]

Second string

Ausgaben

Bezeichnung

Name

Typ

Beschreibung

Concatenation

CONCATENATION

[string]

The concatenated string

Pythoncode

Algorithm ID: native:stringconcatenation

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.

28.1.9.14. Variable distance buffer

Warnung

This algorithm is deprecated and can be removed anytime. Prefer using Buffer algorithm instead.

Computes a buffer area for all the features in an input layer.

The size of the buffer for a given feature is defined by an attribute, so it allows different features to have different buffer sizes.

Siehe auch

Buffer

Parameter

Bezeichnung

Name

Typ

Beschreibung

Input layer

INPUT

[vector: any]

Input vector layer

Distance field

DISTANCE

[tablefield: numeric]

Attribute for the distance radius of the buffer

Segments

SEGMENTS

[number]

Default: 5

Controls the number of line segments to use to approximate a quarter circle when creating rounded offsets.

Dissolve result

DISSOLVE

[boolean]

Default: False

Choose to dissolve the final buffer, resulting in a single feature covering all input features.

../../../../_images/buffer_dissolve1.png

Abb. 28.8 Normal and dissolved buffer

End cap style

END_CAP_STYLE

[enumeration]

Default: Round

Controls how line endings are handled in the buffer.

../../../../_images/buffer_cap_style.png

Abb. 28.9 Round, flat and square cap styles

Join style

JOIN_STYLE

[enumeration]

Default: Round

Specifies whether round, miter or beveled joins should be used when offsetting corners in a line.

Miter limit

MITER_LIMIT

[number]

Default: 2.0

Only applicable for mitered join styles, and controls the maximum distance from the offset curve to use when creating a mitered join.

Ausgaben

Bezeichnung

Name

Typ

Beschreibung

Buffer

OUTPUT

[vector: polygon]

Buffer polygon vector layer.

Pythoncode

Algorithm ID: qgis:variabledistancebuffer

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Verarbeitung Algorithmen von der Konsole aus verwenden for details on how to run processing algorithms from the Python console.