CONTENTS
QGIS can save your Graphical Modeler models in either of 2 locations:
When you click Save model in project, the model is saved inside the current project’s .qgz file.
Models saved this way appear in the Processing Toolbox panel, under Project models, and are only accessible from the current QGIS project.
When you click Save, the model is saved in a single default per-user folder, managed by QGIS.
/Library/Application Support/QGIS/QGIS3/profiles/default/processing/models/ … not exactly obvious.Models saved this way appear in the Processing Toolbox panel, under Models, and are accessible from any of your QGIS projects.
For the purposes of ESM 263, you should use Save model in project:
You’re not going to be building general-purpose models for this class, so there’s no advantage to sharing models between projects.
Saving the model in your .qgz file means you can just hand in the .qgz file when you’re required to submit a model. This may also help us debug your model if there’s a problem with it, since the .qgz file will let us at least partially reproduce the context in which the problem occurs.
If you ever need to save a model as a stand-alone file, you can use Save model as…, which saves the model in a file with a .model3 extension. This shouldn’t be necessary, since saving it in the .qgz file is equally effective, and less buggy.
Once saved, a model can be invoked just like any other tool, either independently, or from another model.
In the graphical modeler, you’ll find the models you saved in the Algorithms panel. This allows you to add the saved model to another model as a submodel.
To edit a saved model, find it in the Processing Toolbox panel in the main QGIS window (i.e., not the graphical modeler). It should be all the way at the bottom. Right click the model and select Edit. (Don’t double-click it; that will run it.)
Occasionally a model will stop responding, and cause QGIS to freeze as well. Usually this is due to an incorrect parameter setting that causes the model to run at too fine a resolution, or over too large an area, or (etc. etc.) Of course, sometimes it’s just a bug. If you’ve been careful about frequently saving your model and your project, you should be able to force-quit QGIS without causing yourself too much pain:
on macOS: Type command-option-esc, which will bring up a Force Quit Applications dialog. Select QGIS from the menu of applications, and click Force Quit.
on Windows: right-click on the taskbar and select Task Manager. Select the QGIS task and click End task.