Graph: Layout (3D XYZ)

From the Help - Animated Overviews submenu, select How To: Dynamic "Data-Graphs" Link to view a multimedia presentation of the use of dynamic features to automatically update graphs.

In the Graph Options dialog tree view, select Layout (under Graph) to access the options described here. Use these options to modify the general layout of 3D XYZ graphs. You can make changes to the axis proportions (e.g., to expose or explore a particular aspect of the data), magnify a specific area of interest, or change the graph type. The options available on this tab vary according to the type of 3D graph created.

Layout settings. Use the Layout Settings group to adjust the axes proportions of your 3D graph.

Axis proportions. Use the Axis proportions drop-down box to set the proportions of the axes in your 3D graph in order to adjust the frame of reference for the graph (axes) to its shape (i.e., in order to expose or explore a particular aspect of the data).

Graph type. Click the Graph type drop-down box to display a list of graph types (Standard, 2D Projection, Space, and Spectral) than can be applied to the current graph.

Standard. Select Standard to draw a standard 3D scatterplot that visualizes a relationship between three variables, representing the X, Y, and Z (vertical) coordinates of each point in 3-dimensional space.

2D Projection. Select 2D Projection to change your 3D graph to a 2D scatterplot; the Z variable will be ignored and the Y variable will be plotted against the X variable. If the current plot is a surface plot, the surface will be indicated by contour lines.

Space. Select Space to represent the 3D scatterplot data and surfaces in a distinctive method through the use of an X-Y plane positioned at a user-selectable level of the vertical z-axis (which "sticks up" through the center of the plane). The level of the X-Y plane can be adjusted by specifying the Deviation level (see below) in order to divide the X-Y-Z- space into meaningful parts (e.g., featuring different patterns of the relation between the three variables).

Spectral. Select Spectral to divide the 3D space into sections and the data points from consecutive sections will be "compressed" into consecutive spectral planes. Values of variables X and Z are interpreted as the x- and z-axis coordinates of each spectral plane, respectively; values of variable Y are clustered into equally-spaced values, corresponding to the locations of the consecutive spectral planes. The number of spectral planes can be adjusted by specifying the desired number in the No. of spectral planes field (see below).

Deviation level. The Deviation level field is applicable to the Space plot. Use this field to specify a value that will determine the Z-level of the X-Y plane in the space plot of your graph.

Enable 3D text representation. When this check box is selected, axes titles and tickmarks are displayed in a 3-dimensional manner.

No. of spectral planes. The No. of spectral planes field is applicable to the Spectral plot. Use this field to specify the number of spectral planes into which the data are to be segmented (compressed).

Marker point reduction. Use the Marker point reduction option to specify an optimization for rendering graphs with large amounts of data. Usually, this option does not affect the overall appearance of the graph, it simply allows for quicker display of the graph when large (i.e., over 100,000 cases) data sets are involved. The default value is Standard, and for most data sets this is the desired setting. With this setting, every point is plotted. When two cases have the same coordinates, the second case is simply plotted over the next case. When Fast is selected, multiple points with the same coordinates are skipped (i.e., only one point with that set of coordinates would be plotted; although all cases are shown in the graph data editor). This considerably reduces the graph drawing time. The Fast option is ideal for larger data sets. The Aggressive option allows for two markers to be considered overlapping even if there is a slight (one pixel) difference between them in the graph. This option still provides a good representation of the data while drawing the graph about four times quicker.

Visual differences might exist when point labels are used in the graph or when the markers are different (e.g., case state markers are used).  For example, when Standard is used in conjunction with point labels (i.e., text values), the labels of overlapping points cannot be read. When Fast is used in conjunction with point labels, the point labels will be easier to read, because only one of the cases (the last one) with those coordinates is actually plotted. Hence, there is only one point label for that location. Another visual difference occurs when point markers are different for subsets of cases (i.e., case states markers are used). When the Standard option is used and points with different markers overlap, you would expect to see fragments of the markers from previous cases (e.g., fragments of a square are still visible when overprinted by a diamond). With the Fast option, only the marker associated with the last case to have those coordinates will be shown.

Zoom area (in scale units). Use the Zoom area group to zoom in on a specific space of the graph (i.e., to magnify a specified space).

Enable. Select the Enable check box to activate the Zoom area options.

X, Y, Z minimum/X, Y, Z maximum. Specify values in the X, Y, Z minimum and X, Y, Z maximum fields to define the space that you want to magnify in your graph. The graph will be redrawn using these minimum and maximum values as ranges for the x, y, and z-axis. Note that if any of these numeric fields are left blank the actual minimum or maximum values for the graph would be applied to the corresponding axis. Once you have used these options, you can easily undo them by clearing the Enable check box or selecting Undo from the Edit menu.

Data update. Use the options under Data update to specify the update method applied to the graph when data change in the data file.

Automatic. Select this option button to specify that the graph data is to be updated automatically when changes are made to the data source. This will be the default setting.

Manual. Select this option button to specify that the graph data is to be updated  manually when the user explicitly requests an update of the graph data.

Locked. Select this option button to specify that the graph data is not to be updated.

Details. Click the Details button to display the Data Update Details dialog, which contains more detailed options to adjust the spreadsheet data source and variable selection used for the graph.

Don't ask before automatic updates on graph with modified data. Select this check box to specify that you don't want to be warned before the automatic update of the graph takes place.

Update on OK. If the Data update mode is set to Manual and this check box is selected, a prompt will be displayed when the source data change, and the graph will be updated when you click the OK button.

Reconnect on load. Select a command from this drop-down list to control how the graph reloads the data from the spreadsheet. The choices are Always, If spreadsheet open, Always ask, and Never.

Update spreadsheet case states. When this check box is selected, the changes of the case states (including the case labels, case excluded, case hidden, Marker color, etc.) made in the graph will be automatically updated to the spreadsheet, so that the spreadsheet that the current graph is based upon will have the same case states as in the graph.

Update Spreadsheet on OK. If this check box is selected, the current graph case states will be updated in the connected spreadsheet when the dialog is closed. If the Update Spreadsheet Case States check box is cleared, then this option can be used to perform a manual update of the spreadsheet case states.

Moveable point labels. Click this button to display the Moveable Labels dialog, where you can set options for moveable labels.