# How to Create a Scatterplot Matrix

Table of Contents

## What is a Scatterplot Matrix

N numeric variables can be paired in a table of charts with N x N cells. This is called a **Scatterplot Matrix**, or **Scatter Matrix**, or **SPLOM**.

Each chart shows a scatterplot for the variables (i, j). The lower-left corner is mirrored in the charts from the upper-right corner, in the sense for each scatterplot chart with vertical axis for variable i, and horizontal axis for variable j, there is a chart with vertical axis for j, and horizontal axis for i.

The main diagonal shows info for one single variable i: either as a **Histogram**, a **Density Plot**, or just the name of the variable.

## Steps to Create a Scatterplot Matrix

Start Visual Xtractor or Data Xtractor. Connect to a database. Create or design a SQL query. Run the query and check the results.

- Display and enable the
**Chart**query builder. - Select two or more numeric columns as
*Point Charts*–.**Scatter Matrix** - Select an optional
, for points with different colors in MultiColor mode.*Category*

## Scatterplot Matrix with Three Variables

The Scatterplot Matrix below combines the charts for three numeric variables, identified by the ** Scatter Matrix** chart selections. Axis titles are displayed only on the left and bottom edges, when we show either Histograms or Density Plots for the individual variables on the main diagonal.

A Scatterplot Matrix is indeed a particular case of **split chart**. It can be also *synchronized*, but the histograms or density plots may not display properly.

## Scatterplot Matrix with Category

When you select an additional numeric column as ** Category**, its distinct values appear as legend items instead. In a multi-color chart, the points related to each category value appear with a different color.

Without a category, you may use the legend items to hide individual charts. With a category, you hide all points, from any Scatter charts, that appear on the same rows with those category values.

## Customize your Scatterplot Matrix

- Show the Scatterplot Matrix as
**multi-color**. With no Category, each chart uses series with different colors. With a Category, the scatter points for each category value get a different color. **Hide the plot axes**all together, to show just rectangular plots in the Scatter charts.- Select between
**Histogram**charts,**Density Plots**or just variable names, to be displayed on the main diagonal. - Hide all the charts from either the upper-right or the lower-left corner. Remark you may turn them back visible one by one from the legend items.
- Continue by using the legend items to hide some charts, or specific points, when a Category is used.

## Conclusion

- Creating a Scatterplot Matrix in Data Xtractor or Visual Xtractor is fast and intuitive: just select two or more numeric columns as
charts.*Scatter Matrix* - Show
**Histograms**or**Density Plots**for the individual variables. - Hide upper or lower corners.
- Add a
, to show points with different colors in all Scatter charts.*Category* - All builtin powerful features of these chart type are common to most other charts: filtering series through the legend items, interactivity, monochrome or grayscale colors, rich axis and data label selections etc.
- Switch to another builtin chart theme, or customize your own, for any possible color or other styles.