Scatter plot

basic

point

Basic scatter plot mapping two numeric variables to position

A scatter plot displays the relationship between two numeric variables by mapping them to x and y positions. This is one of the most fundamental visualization types for exploring correlations and patterns.

Code

VISUALISE bill_len AS x, bill_dep AS y FROM ggsql:penguins
DRAW point
LABEL
  title => 'Penguin Bill Dimensions',
  x => 'Bill Length (mm)',
  y => 'Bill Depth (mm)'

Explanation

VISUALISE ... FROM ggsql:penguins loads the built-in penguins dataset
bill_len AS x, bill_dep AS y maps bill length to the x-axis and bill depth to the y-axis
DRAW point creates a scatter plot using points
LABEL adds descriptive axis labels and a title

Variations

With color by species

We’re adding species AS color to the mapping to colour the points by species.

VISUALISE bill_len AS x, bill_dep AS y, species AS color FROM ggsql:penguins
DRAW point
LABEL
  title => 'Penguin Bill Dimensions by Species',
  x => 'Bill Length (mm)',
  y => 'Bill Depth (mm)'

The color palette can be changed by detailing the SCALE color clause.

VISUALISE bill_len AS x, bill_dep AS y, species AS color FROM ggsql:penguins
DRAW point
SCALE color TO ('DeepSkyBlue', 'Fuchsia', 'Lime')
LABEL
    title => 'Penguin Bill Dimensions by Species',
    x => 'Bill Length (mm)',
    y => 'Bill Depth (mm)'

Encoding even more data using shape

We can also encode a second layer of information by displaying island AS shape.

VISUALISE 
  bill_len AS x, 
  bill_dep AS y, 
  species AS color, 
  island AS shape
FROM ggsql:penguins
DRAW point
LABEL
    title => 'Penguin Bill Dimensions by Species',
    x => 'Bill Length (mm)',
    y => 'Bill Depth (mm)'

Highlighting groups

Using the layer’s FILTER clause we can split the data across layers. Using layer level MAPPING ensures we apply species AS color only to one layer and not the other. The SETTING is used here to directly set a property without mapping data.

VISUALISE
  bill_len AS x,
  bill_dep AS y
FROM ggsql:penguins
DRAW point 
  MAPPING species AS color
  FILTER island == 'Biscoe'
DRAW point 
  SETTING color => 'grey'
  FILTER island != 'Biscoe'