To search the library catalog for GIS data:
in Oskicat do a keyword search for the quoted term "geospatial data" (make sure to include the quotes!) and a place name or theme.
Example: "geospatial data" Vietnam
The Library collects GIS data for areas around the world, with an emphasis on the nine county San Francisco Bay Area and northern California, and makes it available for use on the GIS workstations in the Earth Sciences & Map Library, as well as through GeoData @ UC Berkeley (the Library's geoportal).