Improving Porphyry Copper Prospectivity Mapping with Stacked Ensemble Machine Learning and Feature Contribution Analysis: A Case Study of the Eastern Sirjan 1:250,000 quadrangle map, Iran - Samiei, M. R.; Moradzadeh, A.; Pahlavani, P.; Ghezelbash, R. (ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci., 2026)