Xcelsius in Three Dimensions – No special glasses required!
By David Harper
Xcelsius offers several advantages over a raw spreadsheet display. One advantage is the ability to stack components vertically on the canvas. We tend to think of charts in two dimensions, a horizontal x axis and a vertical y axis, but stacking gives you a third dimension. The applications are limited only by your imagination.
In this article, I will review one such “3-D” data display. The purpose of this Xcelsius visual model is to evaluate the risk of a hypothetical stock. Specifically, a common question in risk analysis is, “What is our worst expected loss on this stock?” One way to answer such question is to generate several hypothetical future price scenarios, and then look at the handful of outcomes that fall to the bottom. In this model, we generate forty random trials and look at the bottom three outcomes. (For reasons beyond the scope of this article, we care about the 38th-ranked outcome, not the very worst outcome. The worst outcome is typically quite extreme and, instead, it is customary to say “we can say with 95% confidence that we will not lose more than our 38th-ranked outcome.”)
But, plotting forty lines creates a dense mass of lines. I wanted to give the viewer a way to “zoom-in” to the bottom three outcomes at the end of the series, as illustrated below:
The zoom-in effect is real: both charts (i.e., the large one and the zoom-in) pull from the same data, so if data changes for the large chart, the smaller zoom-in chart changes also. This effect is not difficult to achieve.
Let’s look at the “vertical stack” from the side:
The basic line chart sits on the Xcelsius canvas, as a normal line chart.
Two components sit on top of (we should really say, “in front of”) the basic line chart: 1) An image component which holds the magnifying glass graphic, and 2) The smaller “zoom-in” chart.
Initially, the image component and the zoom-in chart are not displayed. We want to give the user the power to display them at will.
The Object Browser – Your Guide to the three dimensional world of Xcelsius
The object browser controls, and displays, the stacking order of components on the Xcelsius canvas. The components “on top of” or “in front of” others float to the bottom of the Object Browser list; at the top of the list are the “underneath” components. I recommend that you get familiar with the object browser so you can use it to manipulate objects on the canvas. A right-click on a component name in the object browser gives you the object menu. Here you can move a component “up or down” the list.
1st Step – Place the main chart
Our first step is to create and place the large line chart. Please don’t worry about the details of this chart – it is just a line chart with many series. We could use the zoom in effect for any chart that is dense from a distance; for example, we could do a zoom-in on a bar chart.
2nd Step - The image component
We are working our way “up the stack,” so our next step is to place the image of the magnifying glass. To do this, we simply drag and drop the Image Component on to the Xcelsius canvas. This wonderful component has two tabs. On the General tab, we Import the graphic of the magnifying glass (MagnifyGlass v2.jpg) and we set the Transparency to 50 out of 100 (i.e., semi-transparent). This gives the magnifying glass its see-through effect.
On the Behavior tab, we trigger the Dynamic Visibility that is common to most Xcelsius components. We want the magnifying glass to be turned-off (not visible) until the “zoom in” button on the canvas is pushed. When the zoom-in button is pushed, cell $D$9 of our spreadsheet will change from 0 to 1. That will trigger the Dynamic Visibility of the image component because we linked Display Status (see above, Behavior tab) to cell $D$9.
3rd Step – Add the zoom-in line chart
The third step is to add the smaller, zoom-in chart. This is nothing more than another line chart that pulls from a subset of the same data source.
The important part is under the Behavior tab:
First, we set the Scale Behavior to Manual Scale. I have found, when stacking charts, you often want to set the Scale Behavior to Manual Scale. In this case, we are just limiting the Y-axis to $4 at the bottom and $9 at the top. Second, we trigger Dynamic Visibility – in exactly the same way we did with the magnifying glass. Because we link to the same cell, when the user pushes the zoom-in button, both the magnifying glass and the zoom-in line chart appear, seemingly as one.
You may be wondering, where are we in the stacking order? Let’s look at the object browser:
See how the zoom chart sits in front of (on top of) the magnifying glass, which in turn sits in front of the main Line Chart 1. You will notice that a White Fill rectangle lies in between them. That is not entirely necessary. It is just there to give us extra white space so we can place the legend for the zoom in chart to the lower-left.
Did you notice that we re-labeled the components? If you didn’t notice, perhaps you are still wearing your 3-D glasses and they are obstructing your view. How did we change the name? This is a recommended good practice. A double-click on the name in the Object Browser opens the Properties dialog, but a slow double-click (let’s call this a “click-pause-click”) lets you rename the label. Admit it, you have got to love the software engineers at Xcelsius for little stuff like this. That’s all you need to do. Don’t look now, but we are done – so you can take off your 3-D glasses. You look a little goofy anyway – but of course I mean that in a really nice way!
David Harper is the Principal of Investor Alternatives, LLC, a firm that specializes in investment research, software sector coverage, and derivatives valuation. He is the Editor-in-Chief of Investopedia Advisor, a newsletter devoted to the early recognition of public companies that are likely to be lead future market. He publishes the Bionic Turtle Study Notes, courseware for learning advanced risk management concepts. He is a Charted Financial Analyst (CFA) and Financial Risk Manager (FRM).