10.17028/rd.lboro.7923983.v1 Glenda McMahon Glenda McMahon Ken Chatterton Ken Chatterton True and magnetic north Loughborough University 2019 WEDC Infrastructure in emergencies Technical Diagram International and Development Communication 2019-05-08 13:16:50 Figure https://repository.lboro.ac.uk/articles/figure/True_and_magnetic_north/7923983 True and magnetic north