There are tons of applications of geospatial technology within DH. A colleague of mine described GIS as one of the “low hanging fruits” within DH, I think because location is such a natural paradigm for organizing data which may have few common/known attributes.
-finding, georeferencing/orthorectifying, and sharing geospatial images, such as historical maps (e.g., maptiler, gdal)
-storing, editing, and sharing points, areas, and linear features of interest (e.g., omeka neatline or google maps “my places”/fusion tables)
-combining location with time through intuitive interfaces (e.g, omeka neatline)
-geospatially enabling location based data (e.g., address geocoding, tabular and spatial joins)