I found some Gartner data on IT Spend in 2010. I'll use it to illustrate how to use our charts to map a market. My first example is categorizing IT spend by vertical market. The Gartner data list 10 major vertical markets. A 100% stacked bar is my favorite way to show spend by market. If you place the biggest markets on the bottom, you can quickly compare their relative sizes. Here is my chart:
My only issue is that some of the segments are pretty small. Mekko Graphics has an "Other Series" feature that allows you to group the smaller verticals into a single segment. You can find this feature in the Other Series tab in the Format Series dialog. I added all my verticals with spend of under $150M into "Other Verticals." Here is my chart with the Other Series added:
Sometimes one or more of these smaller series is critical to your analysis. Say you want to target the healthcare vertical. In this case you can explode the Other Series into its own bar. I just copied the data into a new bar and used the "Segment Links" feature to draw the lines between the two bars. Here is my third chart:
I put this deck on Slideshare so that you can open the charts in Mekko Graphics and see how I made them.