Classified Quantitative Symbology for Rasters
This tutorial demonstrates the options for applying a classified color ramp to quantitative values in a raster dataset and choosing the classification method.
Included in this tutorial:
Accessing Symbology Properties
The Symbology Options
Changing the Color Ramp, with an example
Software version in examples: 3.4.0 Bratislava
Tutorial Data: The tutorial includes demonstration with sample data available here.
Credits: L. Meisterlin (2026)
Related Tutorials: The Unclassified Quantitative Symbology for Rasters discusses the default symbology options for rasters in QGIS as well as some of the symbology properties available regardless of classification.
Accessing Symbology Properties
As with vector features, we access a raster’s symbology options through the layer properties, by right-clicking on the layer’s name in the Layers panel and choosing the Symbology tab.
The Symbology Options
We will take a moment to examine the different sections of the Symbology options.
the Singleband Pseudocolor raster symbology options
Under Band Rendering you will find the Render Type. This default option is Singleband Gray: it renders a single raster band in the default grayscale. To access the classified options, first change the Render Type to Singleband pseudocolor.
For classified colors, first set the Interpolation method to Discrete. This will not interpolate (or “stretch”) colors across the values included within the raster dataset. Rather, it will apply a specific color from the color ramp to values within each of the established classes.
You can change your color ramp from the dropdown menu.
Beneath the panel of legend swatches, choose the classification Mode and the number of Classes. (The “Classes” option will be “greyed out” if the interpolation method is not set to “discrete.”) Then click the Classify button to populate the panel of legend swatches.
Click Apply or OK to apply your symbology changes to the map canvas.
Other Options
Under the Min/Max Value Settings, you can customize how the color ramp is “stretched” across the values contained in the raster dataset. This allows you to render faster or more accurately. The options also allow you to account for potential outlier values.
The Layer Rendering options offer more control over the visualization and its legibility by adjusting image contrast, brightness, and other parameters.
The Resampling method options include (as you likely guessed) the resampling methods for visualizing your values as you zoom in and out of the raster (assuming that resampling is necessary based on your map’s zoom level).
Two examples
Below are two examples: an equal interval classification with 10 classes (its options are included in the image above) and a decile classification (quantiles with ten classes).
10 Equal Interval Classification
Decile Classification