ndvi-v1 NDVI computation version 1. martin * MaskFeature 1 L2A_T32VNM_20170705T105031_B04_10m ndvi ndvi L2A_T32VNM_20170705T105031_B08_10m 8 MaskFeature L2A_T32VNM_20170705T105031_B04_10m ndvi L2A_T32VNM_20170705T105031_B08_10m oslo region_mask