# 5.3.1 Matrixsheet Dimensions and XY Coordinates

You can use the Matrix Dimension and Labels dialog to control the number of rows and columns, the X / Y column and row mapping arrangement, and the X / Y column headers, for all matrix objects in a given matrixsheet. Alternately, you can use the mdim X-Function to set the dimensions and coordinates.

Row and column numbers are positive integers. They determine the number of cells in the matrix. If a matrix is a numeric matrix, you can use this dialog to change the dimensions. However, you cannot change the dimensions for images. To determine whether you have an image matrix or a numeric matrix, look at the layer icon. If a matrix object is an image, its object icon will be . Otherwise, it will be .

To open the dialog, select Matrix: Set Dimension/Labels from the menu. ## Matrix Dimension

### Columns * Rows

Enter the number of columns (X dimension) and rows (Y dimension) in the associated text boxes.

### Data will be

For a non-empty matrixsheet, the dimension change will also influence the data. Origin provides two modes to deal with the data in this case, Truncated and Rearranged.

## Coordinates

Type the first and last X / Y values in the associated text boxes under the XY Mapping tab.

The X and Y coordinates of matrix data are assumed to be evenly spaced. The first X is mapped to the first matrix column and the last X is mapped to the last matrix column. The X coordinates of other columns will be linearly mapped. Similar mapping applies to rows, but the first Y and the last Y are used. For a point that corresponds to a matrix cell, its position in 3D space is determined by the X and Y coordinates of this cell, as well as the Z-value that is saved in the cell. When matrix data is plotted or analyzed, it is the XY coordinates, not the column and row numbers, that are used.

## Labels

Enter the Long Name, Units, or Comments for X / Y / Z coordinates under the X Labels, Y Labels or Z Labels tab. X / Y /Z Labels can be used as X / Y /Z axis labels in 3D graphs. For detailed information about the Z Labels tab, please refer to matrix object headers.