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How does a custom function in QGIS work?
We will define a custom function named GetUtmZone that will calculate the UTM zone number for each feature. Since custom functions in QGIS work at the feature level. We will use the centroid of the feature’s geometry and compute the UTM Zone from the latitude and longitude of the centroid geometry.
How are user defined expressions used in QGIS?
Expressions in QGIS have a lot of power and are used in many core features: selection, calculating field values, styling, labelling etc. QGIS also has support for user-defined expressions. With a little bit of python programming, you can define your own functions that can be used within the expression engine.
Where to find the function editor in pyqgis?
Go to or click the Select features using an expression button on the Attributes Toolbar. In the Select by Expression dialog, switch to the Function Editor tab. Here you can write any PyQGIS code that will be executed by the expression engine.
How to write custom expression functions in Python?
Go to Edit ‣ Select ‣ Select Features By Expression… or click the Select features using an expression button on the Attributes Toolbar. In the Select by Expression dialog, switch to the Function Editor tab. Here you can write any PyQGIS code that will be executed by the expression engine.
How to use the map tip tool in QGIS?
One of the hidden gems in QGIS is the Map Tip tool. This tool shows user-defined text when you hover over a feature. Right-click the ne_10m_populated_places_simple layer and select Properties. Switch to the Display tab. Here you can enter any text that will be displayed when you hover over the features of the layer.
Is there wrong indexation for tab in QGIS?
In Windows with QGIS 2.14.1 in the function editor, when I press “enter” to go to the next line, a wrong indexation is introduced. Specifically a “tab” is put at the beginning instead of the 4 “spaces” that are needed in Python.
How to autocomplete an expression in QGIS 14.2?
Autocompletion is available to speed expression writing: Corresponding variables, function names and field names to the input text are shown below: use the Up and Down arrows to browse the items and press Tab to insert in the expression or simply click on the wished item. Function parameters are shown while filling them.