Fundamentals of Scatterplot matrix graphs

A scatterplot matrix graph is a data exploration tool that allows you to compare several datasets to look for patterns and relationships.

The scatterplot matrix (SPM) graph takes a layer or a table as input. You select the fields that you want to use in the graph. The graph has two main components: a matrix of small scatterplots for each of the fields and a larger Preview window that shows the scatterplot for a selected pair of fields in greater detail. You can also enable histograms to be plotted, showing the distribution of values for each of the fields.

Scatter Plot Matrix Wizard

The wizard will lead you through the steps necessary to create a scatterplot matrix graph.

1. Data source—Set the Layer/Table control to the data source you want to create the SPM graph from.
2. Fields—Set the fields that will be used to create the graphs. An SPM graph requires at least three fields to be specified.
   • Click the Field control and choose one of the fields from the list. Repeat this for each field you want to have in the graph.
   • If you want to have all the fields in the source represented, click the Add all fields button.

     You can remove a field you don't want to use by selecting it and choosing <remove> from the drop-down list.

     Use the Clear fields button to remove all the selected fields.

   • Use the Label control to alter the text that will be used as a description for the field. This is commonly used to make shorter versions of long field names.
3. Color—By default, the color of all the graphs will match that of the source layer. If you want to apply a single color to each of the SPM graph elements, set the Color control to Custom and choose the color to use with the color picker control.
4. Symbols—Symbol properties allows you to change the style, size, and shape of the graph elements in the larger Preview graph.
5. Histograms—Click Show Histograms to enable the display of the frequency distribution of values in each of the fields. This is useful to indicate the modality of the values in a particular field and whether they are skewed. The sensitivity of the histograms is managed with the Number of bins control.

The first page of the graph wizard will appear similar to the following:

Note:

When creating the SPM graph, for performance reasons the wizard does not dynamically update whenever a change is made as it does for other graph types. To see the changes, click the Apply button.

After the parameters of the data to use in the SPM have been specified, proceed to the second page of the wizard to set some of the general properties of the graph. Once you complete these steps, the graph will be created in ArcMap as a floating window.

After a graph has been created, you can return to the wizard and make changes by right-clicking on the graph and choosing Properties or by double-clicking on it. See About modifying a graph for more information on making particular changes. Right-clicking on a graph will bring up the Graph Options context menu, which gives several choices on how to display, store, and modify the graph.