Soil Organic Carbon Prediction Based on Vis–NIR Spectral Classification Data Using GWPCA–FCM Algorithm by Yutong Miao 1,†, Haoyu Wang 1,†, Xiaona Huang 2, Kexin Liu 1, Qian Sun 1, Lingtong Meng 1 and Dongyun Xu 1,* 1 College of Resources and Environment, Shandong Ag...