Florida State University has placed the US State Department’s International Boundary Studies online.  They are really useful for getting a high-level description of the history and delimitation of international boundaries around the world.  Most often the studies will not have any maps, but the text will have a description of the boundaries.  Check it out!

Here is a great example on how to use bivariate mapping and color hues to show two subjects that are compared in one map.

The Big Ten Academic Alliance Geoportal is a project that aims to make geospatial resources more discoverable and accessible to scholars. The Geoportal aggregates publicly-available geospatial resources, which are curated by librarians and specialists at twelve universities in the Big Ten Academic Alliance. These resources include GIS datasets, digitized historical maps, and web services, and each item is also accompanied by descriptive metadata along with links to download or view the full resource. They are easily searchable by both text and map and they can also be browsed by place, data type, and subject. The Geoportal’s resources include locations worldwide (including Antarctica), though their coverage is most extensive in the United States. It should be noted that this site does not itself host any data; instead, it serves as a one-stop shop that connects users to data hosted by numerous separate websites.  Check it out!