What are some tips and tricks to create custom symbols and styles in QGIS?

1 Use SVG files for symbols

One of the easiest ways to create custom symbols in QGIS is to use scalable vector graphics (SVG) files. SVG files are images that can be scaled and modified without losing quality or resolution. You can find many free and open-source SVG files online, or create your own using software like Inkscape or Adobe Illustrator. To use SVG files as symbols in QGIS, you need to add them to the SVG paths in the settings menu. Then, you can select them from the symbol selector dialog and adjust their size, color, rotation, and offset.

2 Create rule-based styles

Another way to create custom styles in QGIS is to use rule-based styles. Rule-based styles allow you to apply different styles to different features based on certain conditions or expressions. For example, you can use rule-based styles to color-code your features by attribute values, or to show or hide features based on scale or zoom level. To create rule-based styles in QGIS, you need to open the layer properties dialog and select the rule-based option from the style tab. Then, you can add, edit, or delete rules using the buttons and the expression builder.

3 Use data-defined overrides

A third way to create custom styles in QGIS is to use data-defined overrides. Data-defined overrides allow you to control the appearance of your features based on the values of their attributes or other variables. For example, you can use data-defined overrides to vary the size, color, shape, or transparency of your symbols according to your data. To use data-defined overrides in QGIS, you need to click on the data-defined button next to the style parameter you want to override. Then, you can choose a field, a variable, or an expression to define the value of the parameter.

4 Use geometry generators

A fourth way to create custom styles in QGIS is to use geometry generators. Geometry generators allow you to create new geometries based on the existing ones, using expressions or functions. For example, you can use geometry generators to create buffers, centroids, arrows, or labels based on your features. To use geometry generators in QGIS, you need to select the geometry generator option from the symbol layer type menu. Then, you can write an expression or choose a function to generate the geometry.

5 Use layer blending modes

A fifth way to create custom styles in QGIS is to use layer blending modes. Layer blending modes allow you to change how the colors of different layers interact with each other, creating different effects and contrasts. For example, you can use layer blending modes to highlight or darken certain areas, or to create heat maps or hillshades. To use layer blending modes in QGIS, you need to open the layer rendering panel and select a blending mode from the dropdown menu. You can also adjust the opacity and brightness of each layer.

6 Use print layouts

A sixth way to create custom styles in QGIS is to use print layouts. Print layouts allow you to design and export your maps for printing or publishing, using various elements and tools. For example, you can use print layouts to add titles, legends, scale bars, north arrows, grids, or insets to your maps. You can also adjust the size, position, alignment, and rotation of each element. To use print layouts in QGIS, you need to create a new print layout from the project menu and add the elements you want from the layout toolbar.