The libraries are especially in during semester exams have been full. Before going there, it would be easy  to have a simple app displaying libraries close to one and their occupancy.

Edinburgh University's Libraries use traffic light based system,

with Red light  indicating a full library with no free seats

and a Green light indicating plenty of space.

 See  Traffic light based system 

 

University College London  View

University of Passau      View

 

See Articles on Occupancy Monitoring Application for University Library

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3. Study Hunt: Library seat availability live monitoring system  View