Hui Zhang and Camden Lopez have published "An Interactive Map for Showcasing Repository Impacts>" in Code4Lib Journal.
Here's an excerpt:
Digital repository managers rely on usage metrics such as the number of downloads to demonstrate research visibility and impacts of the repositories. Increasingly, they find that current tools such as spreadsheets and charts are ineffective for revealing important elements of usage, including reader locations, and for attracting the targeted audiences. This article describes the design and development of a readership map that provides an interactive, near-real-time visualization of actual visits to an institutional repository using data from Google Analytics. The readership map exhibits the global impacts of a repository by displaying the city of every view or download together with the title of the scholarship being read and a hyperlink to its page in the repository. We will discuss project motivation and development issues such as authentication with Google API, metadata integration, performance tuning, and data privacy.