How to import QGIS processing in stand-alone Python?

How to import QGIS processing in stand-alone Python?

I want to write a few stand-alone scripts that use the processing toolbox of Qgis. I have read a few threads ( here and here, e.g.) but couldn’t find a working solution yet. Does anyone know what is missing for me to be able to import the processing module?

How do I install QGIS in conda forge?

Install QGIS through conda-forge in the current environment using conda install -c conda-forge qgis. Open QGIS by running qgis. This will create a conda.pth file at the site-package directory, which stores all the environment path variables specified for this conda-qgis environment.

Where do I find QGIS plugins in Python?

Note: QGIS Python plugins are installed here: ~\\.qgis2\\python\\plugins, so you might need to sys.path.append that too. The answer provided by j08lue works for me. But we also could do this in an Anaconda virtual environment in a specific environment-wide way.

How to ask your own question in pyqgis?

Asking for help, clarification, or responding to other answers. Making statements based on opinion; back them up with references or personal experience. To learn more, see our tips on writing great answers. Not the answer you’re looking for? Browse other questions tagged qgis pyqgis qgis-processing or ask your own question.

How to dissolve geometries in a QGIS script?

You will see the selected features highlighted in yellow. Right-click the dissolve_with_sum script and select Execute. Select the inputs as before and click Run. A new output layer will be added to QGIS. This will contain dissolved geometries only from the selected features in the input layer.

How to write new processing algorithms in QGIS?

Within QGIS, you can use Create new script in the Scripts menu at the top of the Processing Toolbox to open the Processing Script Editor where you can write your code. To simplify the task, you can start with a script template by using Create new script from template from the same menu.

Can a pyqgis script be run in QGIS?

PyQGIS scripts are great to automate spatial processing workflows. It’s easy to run these scripts inside QGIS but it can be even more convenient to run PyQGIS scripts without even having to launch QGIS. To create a so-called “stand-alone” PyQGIS script, there are a few things that need to be taken care of.

How to pass a string to a QGIS object?

Simply use a string with the name that identifies the data object to use (the name it has in the QGIS Table of Contents) or a filename (if the corresponding layer is not opened, it will be opened but not added to the map canvas). If you have an instance of a QGIS object representing the layer, you can also pass it as parameter.

How to make a pyqgis script with osgeo4w?

An essential first step is to ensure that all environment variables are set correctly. The most reliable approach is to go to C:\\OSGeo4W64\\bin (or wherever OSGeo4W is installed on your machine), make a copy of qgis-dev-g7.bat (or any other QGIS version that you have installed) and rename it to pycharm.bat:

How to create a processing layer in QGIS?

For convenience, you may directly download a geopackage containing the above layer from below: In the QGIS Browser Panel, locate the directory where you saved your downloaded data. Expand the zip or the gpkg entry and select the ne_10m_admin_0_countries layer. Drag the layer to the canvas. Go to Processing ‣ Toolbox.

How to dissolve with sum in qgis3 script?

In the Dissolve with Sum dialog, select the ne_10m_admin_0_countries as the Input layer. This time, make sure you check the Selected features only box. Choose SUBREGION as the Dissolve field and POP_EST as the Sum field. Once the processing finishes, click Close and switch back to the main QGIS window.

Which is the best class to use in qgis3?

QGIS3 has a new class called QgsFeatureSink which is the preferred way to create objects that can accept new features. The output needs only 2 fields – one for the value of dissolved field and another for the sum of the selected field.

How to create a new script in QGIS?

Within QGIS, you can use Create new scriptin the Scriptsmenu at the top of the Processing Toolboxto open the Processing Script Editorwhere you can write your code. To simplify the task, you can start with a script template by using Create new script from templatefrom the same menu. This opens a template that extends

How to load a.bil file in QGIS?

Each layer is presented with a set of files .bil file containing the actual data, a .hdr file describing the data structure and a .prj file containing the projection information. QGIS can load the .bil file and provided the other files exist in the same directory.

How to run an algorithm in QGIS console?

As we have already mentioned, algorithms can be run using: run () . Its syntax is as follows: Where parameters is a dictionary of parameters that depend on the algorithm you want to run, and is exactly the list that the algorithmHelp () method gives you.

How to enumerate a layer in QGIS table of contents?

Simply use a string with the name that identifies the data object to use (the name it has in the QGIS Table of Contents) or a filename (if the corresponding layer is not opened, it will be opened but not added to the map canvas). If you have an instance of a QGIS object representing the layer, you can also pass it as parameter. Enumeration.

What is the difference between QGIS and pyqgis?

QGIS brings a Python API (see PyQGIS Developer Cookbook for some code sample) to let the user interact with its objects (layers, feature or interface). QGIS also has a Python console. The QGIS Python Console is an interactive shell for the python command executions.

What causes QGIS-python.exe to stop working?

In technical terms, it seems that you now need to instantiate the QApplication object before making the call to QgsApplication.initQgis () — the example program in the book instantiates the QApplication object after calling QgsApplication.initQgis (), which causes the program to crash.

How to turn layers and tables into QGIS objects?

Layers and tables values are strings containing the filepath of the corresponding object. To turn them into a QGIS object, you can use the processing.getObjectFromUri () function. Multiple inputs also have a string value, which contains the filepaths to all selected objects, separated by semicolons (; ).

How to turn multiple inputs into a QGIS object?

To turn them into a QGIS object, you can use the processing.getObjectFromUri () function. Multiple inputs also have a string value, which contains the filepaths to all selected objects, separated by semicolons (; ). Outputs are defined in a similar manner, using the following tags:

How to install a QGIS module in conda?

Create a conda environment using conda create -n conda-qgis and then activate this new environment by using conda activate conda-qgis. Install QGIS through conda-forge in the current environment using conda install -c conda-forge qgis.

How to run algorithms using qgis3 toolbox?

The toolbox provides an easy batch processing interface to run any algorithm on a large number of inputs. See Batch Processing using Processing Framework (QGIS3). But there are cases where you need to incorporate a little bit of custom logic in your batch processing.

Where do I find the console in QGIS?

The QGIS Python Console window can be accessed by using the Python Console item in the Plugins menu. When you select this command, the Python Console will appear in the lower-right corner of the QGIS window. Here’s what the Python Console looks like when you first open it:

Which is the best way to use pyqgis?

It should ideally be handled in a slot that is connected to lastWindowClosed () signal of the application. Consulting the PyQGis documentation, you’ll find that there are four main ways to utilize the PyQGis API: outside QGIS (in the Python shell or creating an applications with PyQt4 and not Tkinter (why import Tkinter twice ?)

What’s the difference between QGIS and standalone applications?

This leads me to believe that the difference is that the QGIS application correctly sets external environment variables, but those variables are not set properly when I run it as a standalone script.

Is there any way to run this script outside of QGIS?

Please…is there some way I can run this script outside of QGIS and have it work as it does within QGIS (ideally without shutting things down at the very end)?

How to write standalone Python scripts using pyqgis?

I have found an old question on this subject here: Writing standalone Python scripts using PyQGIS? and was following its advice, by using the guide here: http://docs.qgis.org/testing/en/docs/pyqgis_developer_cookbook/intro.html#python-applications I found that IDLE did not like the “set at the beggining, so my code looks like this:

How to fix ” no module named qgis.core “?

– Geographic Information Systems Stack Exchange Fixing “ImportError: No module named qgis.core”? First of all, I’m using Python 2.7.3, QGIS 1.8 (Lisboa) on Windows 7 pro 64 bits. Now let’s go to the actual question:

Which is the best way to develop in pyqgis?

This step basically installed the matching python version with the QGIS version you asked, QGIS in your python environment, all the depedencies that it needs (gdal, geos, psycopg2, sqlite, proj, numpy…), setted up the PYTHONPATH to dll and pyd files. So in just a few seconds you have all you need to develop in PyQGIS.