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Where to find QGIS resources in pyqgis script?
PyQGIS custom applications or standalone scripts must be configured to locate the QGIS resources, such as projection information and providers for reading vector and raster layers. QGIS Resources are initialized by adding a few lines to the beginning of your application or script.
What do you need to know about pyqgis development?
Raster Layers 3.3. QgsProject instance 4. Accessing the Table Of Contents (TOC) 4.1. The QgsProject class 4.2. QgsLayerTreeGroup class 5. Using Raster Layers 5.1. Layer Details 5.2. Renderer 5.3. Query Values 6. Using Vector Layers 6.1. Retrieving information about attributes 6.2. Iterating over Vector Layer 6.3. Selecting features 6.4.
How to access the QGIS console in Python?
Now that we’re set, let’s open QGIS’s Python console and get to work! Open it from Plugins > Python console or use the shortcut Ctrl+Alt+P on your keyboard. By default an iface object is imported, which allows the access to the currently active QGIS instance’s user interface.
When to run Python code before QGIS initialization?
You can run Python code just before QGIS initialization completes by setting the PYQGIS_STARTUP environment variable to the path of an existing Python file. This code will run before QGIS initialization is complete.
How to run a QGIS processing algorithm in Python?
You can also run a QGIS Processing algorithm via Python using the processing.runAndLoadResults () function instead of processing.run () as shown above – which will load the result to QGIS canvas directly.
What can I do with the qgis.gui module?
The qgis.gui module provides various GUI components, most notably the map canvas widget that can be incorporated into the application with support for zooming, panning and/or any further custom map tools.
Where do I find the install path for QGIS?
The QGIS install path varies by platform; the easiest way to find it for your your system is to use the Python Consolefrom within QGIS and look at the output from running QgsApplication.prefixPath().
PyQGIS custom applications or standalone scripts must be configured to locate the QGIS resources such as projection information, providers for reading vector and raster layers, etc. QGIS Resources are initialized by adding a few lines to the beginning of your application or script.
What does the ifacevariable do in QGIS?
For interaction with QGIS environment, there is a ifacevariable, which is an instance of QgsInterface. This interface allows access to the map canvas, menus, toolbars and other parts of the QGIS application.
What can I do with the QGIS guimodule?
The qgis.guimodule additionally brings various GUI components, most notably the map canvas widget that can be very easily incorporated into the application with support for zooming, panning and/or any further custom map tools.
What does the iface variable do in QGIS?
For interaction with the QGIS environment, there is an iface variable, which is an instance of QgisInterface . This interface allows access to the map canvas, menus, toolbars and other parts of the QGIS application.
How to configure prefix path in QGIS script?
First we import the qgis.core module and configure the prefix path. The prefix path is the location where QGIS is installed on your system. It is configured in the script by calling the setPrefixPath () method. The second argument of setPrefixPath () is set to True, specifying that default paths are to be used.
Is the QGIS API the same as the C + + API?
The Pythonic QGIS API (pyqgis) is nearly identical to the C++ API. Another good resource for learning how to perform common tasks is to download existing plugins from the plugin repository and examine their code. 1.1.