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QGIS Introduction: Symbolize Data

Symbolize Data

Once you join tabular data to shapefiles in QGIS or have a shapefile with numeric or categorical data, you can symbolize the data using the Style tab in the layer properties:

  1. Double-click or right-click the shapefile/layer you want to symbolize and select Properties.
  2. Click on the Style tab.
  3. Choose between Categorical or Graduated (numerical) symbology depending on the type of data you have.  

Categorical Data

If you have data that is broken into categories (i.e. male or female, hair color, political party, etc.) you will choose the Categorized option.  

  1. Next to the column option, use the drop-down arrow and select Categorized.  Find the field with categorized data (in this case, election data) and select it.
  2. Click Classify and the different categories will populate the Value field.
  3. Click OK.

 

The result will look like this:

Numerical Data

If you have numeric data you want to symbolize (i.e. total population) choose "Graduated" symbology.

  1. Next to the Column option, use the drop-down arrow to select Graduated, and select a field with numerical data.  
  2. Choose a classification mode, define the number of classes, and click on Classify.
  3. You can change the color scheme by clicking on the drop-down arrow next to the Color ramp.
  4. Click OK. 

 

The result will look like this:

Tags: gis, QGIS