Normalized Difference Vegetation Index for Douro Valley based on MODIS

Normalized Difference Vegetation Index (NDVI) calculated using MODIS09 imagery provided by USGS/EROS.The original MODIS09 bands were used as data source and then the ndvi was calculated. NDVI quantifies vegetation by measuring the difference between near-infrared and red light (which vegetation absorbs). NDVI is a standardized way to measure healthy vegetation. High NDVI values indicates healthy vegetation. Each compressed file contains the NDVI by years. Internally each file have an ISO TC 211 metadata with a complete geographical description. spatial resolution: 463.313m format: GeoTiff reference system:SR-ORG 6842 To easily manage the data, each file follow name structure: YYYYMMDD_medgold_workpackage_AoI_sensor_index. YYYYMMDD: Imagery acquisition date medgold: Project name sensor: sensor name workpackage: sectorial workpackage name ( WP2 - Olive Oil Sector, WP3 – Wine Grape sector, WP4- Durum wheat pasta sector) Aoi: Andalusia, Douro Valley. Index: NDVI, NMDI, NDWI Example: 20000218_medgold_wpe_douro_MOD09A1_ndvi

归一化差异植被指数（Normalized Difference Vegetation Index, NDVI）由美国地质调查局/地球资源观测与科学中心（USGS/EROS）提供的MODIS09影像计算得到。本数据集以原始MODIS09波段作为数据源，进而计算得到NDVI。归一化差异植被指数通过测量近红外光与植被吸收的红光之间的差值来量化植被状况，是衡量植被健康状态的标准化方法，较高的NDVI值对应更健康的植被。每个压缩文件按年份存储NDVI数据，文件内部均包含符合ISO TC 211标准的元数据，可提供完整的地理空间描述信息。本数据集相关参数如下：空间分辨率：463.313米；数据格式：GeoTIFF；参考坐标系：SR-ORG 6842。为便于数据管理，所有文件均遵循统一命名规则：YYYYMMDD_medgold_workpackage_AoI_sensor_index。各字段含义分别为：YYYYMMDD为影像获取日期；medgold为项目名称；sensor为传感器名称；workpackage为行业工作包名称（如WP2 - 橄榄油产业领域、WP3 – 酿酒葡萄产业领域、WP4-硬质小麦意面产业领域）；AoI为研究区域，包含安达卢西亚（Andalusia）与杜罗河谷（Douro Valley）；Index为所计算的指数类型，包含NDVI、NMDI、NDWI。命名示例：20000218_medgold_wpe_douro_MOD09A1_ndvi