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

1. View 

2. View

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