It’s kind of late to bring up another platform for sharing online collections – but I just looked at the metro website and they have a workshop on View Share you can use it to make maps, and graphs with your data as well :

“Viewshare is a free, Library-of-Congress-sponsored platform that empowers historians, librarians, archivists and curators to create and customize dynamic interfaces to collections of digital content. Starting from an example spreadsheet or data harvested via OAI-PMH, you will use Viewshare to generate distinct interactive visual interfaces (including maps, timelines, and sophisticated faceted navigation), which you can copy-paste to embed in any webpage. This workshop does not require any particular technical proficiency.”

Here is a link to the View Share site: