While this post does not address a math problem, it does address an important aspect of mathematics -- the presentation of data. I occasionally have to prepare information on various items for our Customer Service group. For a number of years, I have maintained a graphic that shows the average cost of a kW-hr of energy by state. Our customers use this data to estimate the yearly operating cost of our equipment in their deployments. I get the statistics from the Department of Energy (DoE) Website. It is a hassle to manually update all 50 states and DC, so I use a spreadsheet to link the data I download from the DoE to Visio. It gives me the graphic you see below. I got the original map of North America from the Visguy website.
I actually use this approach to update a number of graphics. I thought it may be useful for me to include it here as a model for people to use when linking Excel data to Visio. I have included a link at the bottom of this post to a zip file that contains the Excel spreadsheet and Visio drawing I use. When you extract the files, they will go into a directory called "North America." Just run the Visio file from that directory. It should be able to find the spreadsheet. I do not know how to setup a relative address in Windows, but this works on my machines.
You can force an update of the graphic by going to the Visio data tab and clicking refresh all.
Here is my source material: NorthAmerica.zip