Anchoring Objects to Coordinates

STATISTICA graphs can be customized by inserting objects of various types, shapes, and sizes, such as arrows, custom text, drawings, etc. These objects can be "attached" to the graph in one of two ways: Either objects can be attached to specific coordinates in the graph defined for a particular plot (dynamic anchoring), or objects can be placed in the graph at a specific location that is independent of the scaling of the axes.

The distinction between dynamic and non-dynamic (fixed) anchoring of objects is best illustrated with an arrow and custom text, pointing to a particular point marker in a 2D scatterplot. Shown below are two arrows with text pointing to the same location in the graph, with the {x,y} coordinate {2,2}.

The text and arrow to the left ("Dynamic Text and Arrow") were attached dynamically, i.e., the Dynamic check box was selected on the Text Object Properties dialog, and the Arrow Objects Properties dialog. Note that the Arrow Objects Properties dialog allows you to attach independently the arrow head and arrow tail, and in this example the Dynamic check box was selected for both. The text ("Non-Dynamic (Fixed) Text and Arrow") to the right was attached non-dynamically, so the Dynamic check boxes were not cleared for either the text, the arrow head, nor the arrow tail.

Now suppose that you rescaled the horizontal x-axis for this plot to 0 <= x <= 10 (and assume that the values for the plot shown in the scatterplot were plotted against the default lower x-axis). Here is the updated graph after rescaling the x-axis.

As you can see, the Dynamic Text and Arrow are still attached to the same plot point, i.e., they moved dynamically with it because they were attached dynamically to the coordinate system for this plot, and to a specific pair of coordinates within this plot. The Non-Dynamic (fixed) Text and Arrow are in precisely the same position relative to the overall graph area as before, i.e., their locations were not affected by the rescaling of the graph.

Applications. Both methods for attaching objects to locations in a graph are useful for different purposes. The dynamic placement of objects assures that the relationship between plotted points, bars, etc. in the graph and the respective objects remains the same; an arrow pointing to a specific plot point is a good example of this scenario. However, sometimes you want to place some labels in a particular place in the graph, regardless of what the graph is showing or how it is scaled. This could be the case for legends, which you may always want to show, for example, in the upper-left corner of the graph.