I thank Mario Sánchez-Gómez(UJA-CEACTEMA)for his advice on this work,and my colleagues from the Topo-Iberia team for contributing information and site photographs:Antonio M.Ruiz-Armenteros(UJA),Giorgi Khazaradze(UB),Jorge Gárate Pasquín(ROA),the late Manuel Catalán-Morollón(ROA),José M.Llorente Delgado(IGME),Agustín González Durán(IGME),and especially Juliana M.Martín León(IGME).I also thank Maya García-Comas and the staff of the Sierra Nevada Observatory,operated by the Instituto de Astrofísica de Andalucía(IAA-CSIC),for watching over the GNSS station NEVA and for granting permission to use its images.I further thank the University of Jaén and the Spanish Ministry of Economy,Industry and Competitiveness for partially supporting this research through grant PTA2015-11507-I.Finally,I thank two anonymous reviewers for their constructive and helpful comments and suggestions,which have considerably improved and expanded this study. （UJA-CEACTEMA）