This dialog is opened when you select the **Convert to Matrix -> Regular XYZ...** command from the **Convert to Matrix** menu.
It allows to customize the process of generating a new matrix from a table that contains regularly spaced XY data.

If the *Preview* box is checked, this dialog displays in the *Grid* tab a 2D scatter
plot of the Y versus X data columns that are associated with the selected Z dataset.
This graph allows to check the regularity of the input data: the spacing in the X and Y dimensions should be regular.

In order for the input data to be classified as regular, the values in the X and Y columns must meet specific requirements: each X value must have the same number of Y values and each Y value must have the same number of X values. In addition, both the X and the Y data values must be equally spaced: only small irregularities of the data are allowed.

The value of the tolerance for irregularities in both X and Y directions can be customized via the *Tolerance for Duplicate X* and
*Tolerance for Duplicate Y* input boxes, respectively. These two input values must be between 0 and 1.

For two adjacent data points (x_{1}, y_{1}, z_{1}) and (x_{2}, y_{2}, z_{2}),
if |(x_{1} - x_{2})/(x_{1} + x_{2})| < Tolerance_{X} the two X values are considered to be duplicates.
The same formula is applied in the Y direction: if |(y_{1} - y_{2})/(y_{1} + y_{2})| < Tolerance_{Y}
than the two Y values are also considered to be duplicates.

The *Replace Duplicates With* list box is useful if several Z values correspond to the same XY data pairs within the user specified tolerances.
The user can choose how these Z values should be combined into a single value. The possible ways to generate a single Z value are:

- Mean:
the mean of the duplicate Z values is used (default functioning mode).

- Minimum Value:
the minimum Z value is used.

- Maximum Value:
the maximum Z value is used.

- Sum:
the sum of the duplicate Z values is used.

- None:
the last of the duplicate Z values is used.

If the *Preview* box is checked, this dialog also displays a 3D plot preview of the resulting matrix together with a scatter plot of the input XYZ data points
in the *3D Surface* tab. The aspect of the 3D preview surface can be fully customized using the *Plot type* and *Floor style* controls.

If the option *Create Plot* is checked, QtiPlot also creates a 3D plot window of the result matrix when the *OK* button is pressed,
using the settings specified in the *Plot type* and *Floor style* controls.