Evaluating drought index using NDDI method on toposequence of the Western Lawu Mountain, Karanganyar Regency, IndonesiaRahayu Rahayu, Aktavia Herawati, Sumani Sumani, Mujiyo Mujiyo, Ganjar Herdiansyah and Fitria Dewi QomariahE3S Web Conf., 682 (2025) 01027DOI: https://doi.org/10.1051/e3sconf/202568201027