geom_line

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geom_line connects the observations in order of the variable on the x axis

Aesthetics

Other Properties

Similar Geometries

geom_path, geom_step

Description and Details

Using the described geometry, you can insert a simple geometric object into your data visualization – a line defined by positional aesthetic properties x and y, where data are ordered according to variable on x-axis. You can find this geometry in the ribbon toolbar tab Layers, under the 2D button.

If you Plot temporal data (time-series), they need to be always ordered according to x-axis, before visualization. For this purpose, you can use geom_line, which is defined by two positional aesthetic properties – x and y. The example is shown in the following figure, where we have displayed the progress of the unemploy variable in time from the built-in economics dataset.

The structure of dataset in the second example is shown in the following table. In this case, we have in table three variables. In table are stored multiple variables that are identified by variable column. Data in this dataset are stored in the long form (more about long form here).

date	value01	variable
1.1.2016	0.52	pce
2.1.2016	0.45	pce
1.1.2016	0.75	pop
2.1.2016	0.74	pop
3.1.2016	0.95	pop
...	...	...

If you want to use them, you map selected variables to positional aesthetics as in the following figure.

All values were rendered as one geometric object (line). Program did not know how to divide these values into separate lines so that the program draws them using one line. If you want to divide them, you are using another aesthetic property that will be mapped to selected categorical dataset variable. If you want all lines to have the same visual character (e.g. color), map this categorical variable to the group aesthetic. In the following example, we have divided them using the color aesthetic property. The program subsequently split the data by the selected variable and renders them as separate lines with different color. The result is shown in the following visualization.

In the following example, we'll use the same data, but the result will be different. The only parameter we change is the position property. From the default (identity) value we set it to stack. According to this setting will be lines stacked each other. The result is displayed in the following plot.

If you use the geom_line, you can define the color aes only for the entire line. If you want to define the color for the individual line segments, use more appropriate geometry – geom_path, which is defined in the same way.