3D array

The dialog 3D array is used to perform the settings for the three-dimensional representation of a data set from a file. The data are represented as a surface y(x,z) described by a smoothing spline interpolation. The dialog is divided into three pages.


On the page Array in the group Data using the button with the open symbol a dialog can be opened to select a data file. The decimal symbol for reading the file can be selected in this dialog. The actual path is displayed left to the button. The button on the right hand side can be used to reload a data file after changing its contents.

By checking Internal Data the array data can be saved within the plot file. For reasons of performance this should only done with data sets not to large. Only the columns selected for plotting will be stored. Internal data can be entered or changed by use of Edit. After unchecking of Internal Data a file selection dialog will be opened to select a separate data file for (re)exporting.

In x column, y column, and z column the file columns for the cordinates of the three-dimensional plot may be chosen. 0 corresponds to the first column. Data are represented as a surface y(x,z). When Error bar is checked, the column chosen in Error column is used as the standard deviation of the y values for weighing the data points when the smoothing spline is calculated. The Smoothing factor affects the average deviation between the spine function and the y values of the data set, and in this case it determines the factor, by which in the average the deviation should be different to the error of the data points. A value of 0 leads to a non-smoothing spline. In this case the x and z coordinates of the array have to fall on a grid. In case of a smoothing spline the coordinates may be placed randomly in the x,z plane. When Error column is not checked, the value of the smoothing factor is taken as the constant standard deviation of the y values.

The Start index is the row index for the first data point to be taken to calculate the surface y(x,z). 0 corresponds to the first row of the data file, not counting comment lines. Together with the Number of points the portion of the file used for calculating the spline is selected. With xmin, xmax, zmin, and zmax the limits for the displayed region of the surface y(x,z) and for the x and z axis are set. The step sizes  Δx and Δz determine the intervals of the grid which represents the surface. Values of 0 result in automatically dividing the respective range into 40 intervals. With ymin and ymax the limits of the y axis are set. The scaling can be set to logarithmic individually for the axes by checking log.


On the page Scaling in the group Window the rectangular range where the three-dimensional plot is shown can be set in cm. A frame around this rectangle is drawn optionally.

In the group Reference Point the distances from the center of the plane spread by the x and z axes at ymin to the left and bottom sides of the window may be set in cm.

In the group 3D box the lengths of the x, y, and z axis of the three-dimensional plot can be set in cm.

The Rotation of the coordinate frame can be set by the angles phi and theta. The value of phi determines the rotation around the y axis, the value of theta determines the tilt of the y axis.

The group Axes allows to specify the distances xtic, ytic, and ztic of major (labeled) tick marks. The number of intervals dividing the distance between the major ticks can be specified by  mticx, mticy, and mticz. For axes with numeric labels the number of digits behind the decimal point may be selected by  ndigx and ndigy. Here values of -1 are used to suppress the output of the decimal point.

Factors for Normalization of the x, y, and z axis may be entered manually. These factors also may be determined automatically using Autoscale with checked Normalization. Autoscaling also sets the limits of the axes, the distances between major tick marks, the number of intervals between major tick marks, the number of digits for numeric labels, the Reference Point, and the lengths of the axes.


On the page Representation in the group Axis mode it can be selected to plot tick marks with and without numeric labels.

In the group 3D mode it can be selected if the surface y(x,z) should be represented by lines in x or z direction or by a grid of lines in x and z direction.

In the group Colors the colors for frame, tick marks, and the surface representing the data may be chosen using the dialog Select Color, opened with the colored buttons.

By Show frame the display of a frame around the rectangular window of the plot can be selected. The relative Line width of the surface grid (proportional to the width of the data window) may be specified. A setting of 100 % corresponds to the default.

A table with values of the plotted surfaces can be exported as a data file using the button  Export. A file selection dialog will be opened for this purpose.

The dialog may be canceled without saving by use of the button Cancel. By using Apply changes are saved without closing the dialog. With OK changes are saved and the dialog is closed.