Normalized Difference Vegetation Index for Andalusia Region based on MODIS

<strong>Normalized Difference Vegetation Index</strong> (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. <br> 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<br> format: GeoTiff<br> 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 – Grape Wine sector, WP4- Durum wheat pasta sector) AoI: Andalusia, Douro Valley. Index: NDVI, NMDI, NDWI Example: 20000218_medgold_wp2_andalusia_MOD09A1_ndvi<strong>标准化差值植被指数（Normalized Difference Vegetation Index，NDVI）</strong> 由美国地质调查局/地球资源观测系统（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。NDVI通过测量近红外光与植被吸收的红光之间的差值，实现对植被状况的量化评估，是评估健康植被的标准化手段。NDVI数值越高，代表植被健康状态越好。<br> 每个压缩文件按年份存储NDVI数据，内部均附带符合ISO TC 211标准的元数据，包含完整的地理空间描述信息。空间分辨率为463.313米，数据格式为GeoTiff，参考坐标系为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。其中，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-橄榄油产业板块、WP3-葡萄酒产业板块、WP4-硬质小麦意面产业板块）；AoI为研究区域，涵盖安达卢西亚与杜罗河谷；index为指数类型，可选NDVI、NMDI、NDWI。示例文件名：20000218_medgold_wp2_andalusia_MOD09A1_ndvi