Beyond the basic single variable graph
Many technical graphs show multiple variables on a single graph. One example of this is to use different types of plots on the same graph. For instance, you can have a bar chart and a line/scatter plot on the same graph. Other users use multiple axes to show widely different variables side by side using the same type of plot. Having the ability to show different types of graphs or different scales on the same graph is critical in visual data analysis. These graphs can be easily created in Grapher with a little bit of manipulation.
Creating stacked graphs
Stacked graphs are useful when displaying data with significantly different Y scales over the same X data range. They can also be used to display the same data in different formats, such as a bar chart and a line plot. Instructions for creating stacked graphs in Grapher can be found in the article How can I create a stacked graph with multiple Y axes in Grapher?
A stacked graph is shown with two
line/scatter plots on different Y axes.
Any portion of either graph can be changed to get the desired appearance. The X axis is shared between the stacked graphs, so comparisons between graphs is possible.
Creating overlaid graphs
Another common way of showing multiple variable graphs is to show the graphs "overlaid" with a shared Y axis or multiple180 Y axes that are on either side of the X axis. Our Surfer users are familiar with the thought of creating multiple maps and using an Overlay command to put the maps all onto a single set of axes. In Grapher, the Add to Graph commands make adding additional plots or axes easy. The article How Can I Overlay Two Plots In Grapher? gives instructions for creating two plots that share both an X and Y axis.
This graph shows overlaid bar and line/scatter plots
Scaling multiple graphs to fit
Occasionally, the plots will be directly on top of one another. This could obscure important information on one graph. So, it may be necessary to add an additional axis to alter the scale of one graph. Information about adding additional axes to a graph and scaling them can be found in the article How Can I Add A Second Axis To My Graph In Grapher?.
This graph shows different scales on the two axes.
Creating more complex graphs
Combining the two types of graphs mentioned above (stacked and overlaid), you can create any number of complex graphs in Grapher. In addition to adding extra plots or axes, you can add legends, text boxes, and other drawn objects. You can also create entirely new graphs, such as pie charts or polar plots to add detail to an existing complex graph. An example is below.
A complex graph showing multiple variables
on stacked and "overlaid" axes.
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Updated September 21, 2018